Environment The Science Behind the Stories, 7th EditionJay H Withgott Solution Manual

Environment The Science Behind the Stories, 7th Edition

BY

Jay H Withgott

Email: Richard@qwconsultancy.com

1 Science and Sustainability: An Introduction to Environmental Science Chapter Objectives This chapter will help students: Describe the field of environmental science Explain the importance of natural resources and ecosystem services to our lives Discuss population growth, resource consumption, and their consequences Explain what is meant by an ecological footprint Describe the scientific method and the process of science Identify major pressures on the global environment Discuss the concept of sustainability, and describe sustainable solutions being pursued on campuses and across the world

Lecture Outline I.

Our Island, Earth 1. The astronaut’s view of Earth reveals that its systems are finite and limited.

2. As our population, technological power, and resource consumption all increase, so does our capacity to alter our surroundings and damage the very systems that keep us alive.

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A. Our environment surrounds us.

1. Our environment consists of all the living and nonliving things around us.

2. We are part of the “natural” world, and our interactions with the rest of it matter a great deal.

B. Environmental science explores our interactions with the world.

1. We have modified our environment.

2. Environmental science is the scientific study of how the natural world works, how our environment affects us, and how we affect our environment.

3. Environmental scientists study the issues most centrally important to our world and its future.

C. We rely on natural resources.

1. Natural resources are the substances and energy sources we take from our environment and that we rely on to survive.

2. Renewable natural resources, such as sunlight, wind, and wave energy, are perpetually renewed and essentially inexhaustible.

Nonrenewable natural resources, such as minerals and fossil fuels, are in finite supply and are formed far more slowly than we use them. Once we deplete a nonrenewable resource, it is no longer available.

D. We rely on ecosystem services.

1. Our planet’s ecological systems purify air and water, cycle nutrients, regulate climate, pollinate plants, and recycle our waste.

Such essential services are commonly called ecosystem services.

2. In recent years, our depletion of nature’s goods and our disruption of nature’s services have intensified, driven by rising resource consumption and a human population that grows larger every day.

E. Population growth amplifies our impact.

1. Today, our population has grown beyond 7 billion people.

2. Two phenomena triggered our remarkable increase in population size. The agricultural revolution occurred around 10,000 years ago as humans transitioned from a hunter-gatherer lifestyle to an agricultural way of life.

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3. The industrial revolution began in the mid-1700s. It entailed a shift from rural life, animal-powered agriculture, and hand-crafted goods toward an urban society provisioned by the mass production of factory-made goods and powered by fossil fuels (nonrenewable energy sources including oil, coal, and natural gas).

4. Our sheer numbers are putting unprecedented stress on natural systems and the availability of resources.

F. Resource consumption exerts social and environmental pressures.

1. Industrialization increased the amount of resources each of us consumes.

2. One way to quantify resource consumption is to use the concept of the ecological footprint, which expresses the cumulative area of biologically productive land and water required to provide the resources a person or population consumes and to dispose of or recycle the waste the person or population produces.

3. Wackernagel and his colleagues calculate that our species is now using 69% more of the planet’s renewable resources than are available on a sustainable basis. This excess use has been termed overshoot.

4. People from wealthy nations have much larger ecological footprints than do people from poorer nations.

G. Environmental science can help us learn from mistakes.

1. Historical evidence suggests that civilizations can crumble when pressures from population and consumption overwhelm resource availability.

2. If we cannot forge sustainable solutions to our problems, then the resulting societal collapse will be global. Fortunately, environmental science holds keys to building a better world.

II.

Environmental Science 1. Environmental scientists aim to comprehend how Earth’s natural systems function, how these systems affect people, and how we influence those systems.

2. Solutions are applications of environmental science.

A. Environmental science is interdisciplinary.

1. Environmental science is interdisciplinary, bringing techniques, perspectives, and research results from multiple disciplines together into a broad synthesis.

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2. Interdisciplinary fields are valuable because their practitioners consolidate and synthesize the specialized knowledge from many disciplines and make sense of it in a broad context.

3. Environmental science is broad because it encompasses not only the natural sciences but also the social sciences. Most environmental science programs focus more on the natural sciences, whereas programs that emphasize the social sciences often use the term environmental studies.

4. An interdisciplinary approach to addressing environmental problems can produce effective solutions for society.

B. Environmental science is not the same as environmentalism.

1. Environmental science involves the scientific study of the environment and our interactions with it.

2. Environmentalism is a social movement dedicated to protecting the natural world from undesirable changes brought about by human actions.

III.

The Nature of Science 1. Science is a systematic process for learning about the world and testing our understanding of it.

2. Knowledge gained from science can be applied to address society’s needs.

3. Virtually everything in our lives has been improved by the application of science.

A. Scientists test ideas by critically examining evidence.

1. Scientists examine how the world works by making observations, taking measurements, and testing whether their ideas are supported by evidence.

2. A great deal of scientific work is descriptive science, research in which scientists gather basic information about organisms, materials, systems, or processes that are not yet well known.

3. Once enough basic information is known about a subject, scientists can begin posing questions that seek deeper explanations about how and why things are the way they are. At this point, scientists may pursue hypothesis-driven science, research that proceeds in a more targeted and structured manner, using experiments to test hypotheses within a framework traditionally known as the scientific method.

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B. The scientific method is the traditional approach to research.

1. The scientific method is a technique for testing ideas with observations.

2. The steps of the scientific method are: a. Make observations. b. Ask questions. c. Develop a hypothesis. A hypothesis is a statement that attempts to explain a phenomenon or answer a scientific question. d. Make predictions. A prediction is a specific statement that can be directly and unequivocally tested. e. Test the predictions. An experiment is an activity designed to test the validity of a prediction or hypothesis; it involves manipulating variables, or conditions that can change. The independent variable is the variable that the scientist manipulates while the dependent variable is the one that depends on the independent variable. Scientists conduct controlled experiments by controlling for the effects of all variables except the tested one. Often, controlled experiments have a treatment area that is manipulated and another that is not, called a control. f. Analyze and interpret results. Scientists record data, or information, from their studies and analyze the data using statistical tests. If experiments disprove a hypothesis, the scientist will reject it and may formulate a new hypothesis to replace it. If experiments fail to disprove a hypothesis, this lends support to the hypothesis but does not prove it is correct. g. A manipulative experiment is an experiment in which the researcher actively chooses and manipulates the independent variable. h. Researchers conduct natural experiments to test their hypothesis by searching for correlation, or statistical association among variables. i. This type of evidence is not as strong as the causal demonstration that manipulative experiments can provide, but often a natural experiment is the only feasible approach.

C. Scientists use graphs to represent data visually.

1. To summarize and present the data they obtain, scientists often use graphs.

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a. Graphs help make patterns and trends in the data visually apparent and easy to understand. b. Note: Consult APPENDIX A: HOW TO INTERPRET GRAPHS for an explanation of different types of graphs.

D. The scientific process continues beyond the scientific method.

1. To have impact, a researcher’s work must be published and made accessible to the community. The scientific method is embedded in this larger process, including: a. Peer review. Research results are submitted to a journal for publication. Other scientists who specialize in the subject area are asked to provide comments and criticism and judge whether the work merits publication. This process is known as peer review. b. Conference presentations. Scientists frequently present their work at professional conferences and receive comments on their research. c. Grants and funding. Most scientists spend considerable time writing grant applications to private foundations or government agencies for support of their research. Conflicts of interest sometimes arise when results are in conflict with the interests of the funding agency. d. Repeatability. The careful scientist may test a hypothesis repeatedly in various ways before submitting it for publication.

After publication, other scientists will attempt to reproduce the results in their own experiments. e. Theories. If a hypothesis survives repeated testing by numerous research teams, it may be incorporated into a theory. A theory is a widely accepted, well-tested explanation of one or more cause-and-effect relationships that has been extensively validated by a great amount of research. In science, a theory is not speculation or hypothesis.

E. Paradigm shifts occur.

1. A paradigm is a dominant view regarding a topic, and the “shift” is when one is abandoned for another.

2. Paradigm shifts demonstrate the strength and vitality of science, showing science to be a process that refines and improves itself through time.

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3. Understanding how science works is vital to assessing how scientific interpretations progress through time as information accrues.

F. How can we judge the reliability of information?

1. Developing careful, logical, critical thinking skills can help everyone interpret information in our society.

2. To determine whether a source is reliable, a reader should ascertain whether the source is objective, unbiased, and evidence-based. a. Scientific journals themselves provide the most accurate sources of information. These scientific journal articles are examples of primary sources. b. Well-established media outlets such as Scientific American, National Geographic, or The New York Times also provide reliable scientific reporting. These secondary sources are produced by others about the contents of a primary source.

IV.

Seeking a Sustainable Future 1. Society’s primary challenge today is finding out how to live within our planet’s means, such that Earth and its resources can sustain us—and all life—for the future. This is the challenge of sustainability, a guiding principle of modern environmental science.

A. Population and consumption drive environmental impact.

1. Like rising population, rising per capita consumption magnifies the demands we make on our environment.

2. Discrepancies in affluence lead to large differences in the ecological footprint of citizens from different nations.

B. Energy choices will shape our future.

1. Our reliance on fossil fuels amplifies virtually every impact we exert on our environment.

2. In extracting coal, oil, and natural gas, we are splurging on a onetime bonanza because these fuels are nonrenewable and in finite supply. Attempts to reach further for new fossil fuel sources all seem to threaten more impact for relatively less fuel.

C. Sustainable solutions abound.

1. Many workable solutions are at hand. a. Renewable energy sources are beginning to replace fossil fuels, and energy-efficiency efforts are gaining ground. b. Scientists are pursuing soil conservation, high-efficiency irrigation, and organic agriculture.

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c. Laws and new technologies have reduced air and water pollution in wealthier societies. d. Conservation biologists are helping to protect habitats and safeguard endangered species. e. Better waste management is helping us to conserve resources. f. Governments, businesses, and individuals are taking steps to reduce the emissions of greenhouse gases that drive climate change.

2. These are a few of many efforts.

D. Students are promoting solutions.

1. Proponents of campus sustainability seek ways to help colleges and universities reduce their ecological footprints.

2. Colleges and universities are centers of lavish resource consumption.

3. Reducing the ecological footprint of a campus can be challenging.

4. Students, faculty, staff, and administrators on thousands of campuses are working together to make the operations of educational institutions more sustainable.

E. Environmental science prepares you for the future.

1. As our society comes to appreciate the challenges of creating a sustainable future, colleges and universities are helping students to learn how to confront these challenges.

2. At most schools, fewer than half of students take even a single course on the basic functions of Earth’s natural systems, and still fewer take courses on the links between human activity and sustainability.

3. Environmental literacy is a basic understanding of Earth’s physical and living systems and how we interact with them.

4. Students taking environmental science will be better qualified for the green-collar job opportunities of today and tomorrow. They will also be better prepared to navigate the many challenges of creating a sustainable future.

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Key Terms agricultural revolution campus sustainability control controlled experiment correlation data dependent variable descriptive science ecological footprint ecosystem services environment environmental literacy environmental science environmental studies environmentalism experiment fossil fuels hypothesis hypothesis-driven science

independent variable industrial revolution interdisciplinary natural capital natural resources natural sciences nonrenewable natural resources overshoot paradigm peer review predictions renewable natural resources science scientific method social sciences sustainability theory treatment variables

Teaching Tips 1. Begin class by asking students to define the term environment in their own words, on an index card. In addition, have the students find an image in a magazine that matches their definition and attach it to the other side of the index card. Collect the cards. At the end of the semester, return the cards to the students and ask them to redefine the term based on what they learned during the course. Also ask them to evaluate the image—is this what they think of now when they hear the term “environment”? Lead a discussion about how their definitions changed.

2. To teach the scientific method, present a situation to the class and ask students to work in groups to address the issue using the scientific process. For example: A farmer in South Carolina notices that the pond on his property contains an unusually high amount of algae. Because of the algal growth, his cattle will not drink from the pond. Based on this information (the observation), ask students to formulate a hypothesis, make a prediction, and design an experiment.

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3. To make environmental science more appealing, have students investigate local environmental issues so they can relate to them personally and realize that they can make a difference. One possibility is for students to look at the Environmental Protection Agency’s Superfund Sites in their state. The National Priorities List of sites in the United States can be found at: www.epa.gov/superfund/sites/npl/. From there they can choose their state or territory. They can click on any site shown on the state map to see names and locations. They then can click on the site name to go to a page devoted to that site, its description, cleanup approach, progress, potentially responsible parties, and many other site-related documents.

4. Ask students to conduct an Internet search about Easter Island. What is it like today? How many people live on the island? What are the main resources?

Now tell them to research one of the success stories, the island of Tikopia, which lies in the Pacific Ocean east of Australia and New Guinea, west of Tonga and Fiji. Refer to Jared Diamond’s book Collapse (2005, Viking Press).

Ask students to compare and contrast the stable culture that has lasted at least 3,000 years on Tikopia with the fallen and failed culture of Easter Island. What are the major differences in how the people approached the idea of sustainability?

5. Quick feedback: Use a technique known as “muddiest point” to assess student understanding of the material. During the last five minutes of class, pass out 3 × 5 cards and ask students to anonymously write down the one point from the lecture that they don’t quite grasp—the “muddiest point.” Students leave cards in a pile as they exit. You don’t need to read every one of them in a large class—a random sample will indicate whether there are a couple of concepts that many students find unclear, or whether most everyone understood most everything. The technique has two benefits: First, the students must engage in some higher-order thinking to quickly review the lesson and their notes, assessing for clarity; and, second, you will learn whether there are small, scattered misunderstandings or a single issue that needs to be revisited. (From Thomas A. Angelo and K. Patricia Cross, Classroom Assessment Techniques: A Handbook for College Teachers, 2nd ed., San Francisco, Jossey-Bass Publishers, 1993.)

6. Divide the class into six teams. Assign a chapter from Overshoot by William Catton, Jr. (see text reference below) to each team. Ask students to summarize the main points, analyze the information presented by the author, and explain if or how the text is relevant today. Encourage discussion about how issues raised in the text were addressed with legislation and action. Consider dividing students into small groups, each having responsibility for making an oral presentation during the semester.

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7. Consider dividing students into small groups, each having responsibility for a “teach back” during the semester—repeating chapter content, or using an application of that content. This chapter’s group might investigate the ecological footprint of the community where the school is located and explore its sustainability issues. They might investigate whether there are identifiable groups impacted by current transportation or energy issues in the community.

8. Community service: Ask students to brainstorm, individually or as a group, ways in which they might explore the issues of this chapter in their community and take action. A specific example might be to educate consumers about the use of phosphates in dishwashing detergents. If your course contains a service learning or community service component, some students might want to take an idea from this section as a project.

Additional Resources Websites 1. NASA Education, NASA (ww.nasa.gov/audience/foreducators/ index.html) This website provides educator guides for life science activities that integrate the scientific method.

2. U.S. and World Population Clock—POPClock, US Census Bureau (www.census.gov/popclock) This website provides the current total population of the world as well as a plethora of demographic information.

3. Earth Day Network—Ecological Footprint Calculator (www.earthday.org/take-action/footprint-calculator) This simple ecological footprint calculator allows college students to see their demand on resources through answering a few simple questions.

4. The Millennium Ecosystem Assessment (www.millenniumassessment.org/en/index.html) A comprehensive website containing reports and summaries of the commission’s work.

5. AASHE (Association for the Advancement of Sustainability in Higher Education) Campus Sustainability Hub (www.aashe.org) This website contains seemingly unlimited sustainability resources and also sustainable actions taken by institutions of higher education.

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Audiovisual Materials 1. Earth on Edge, Bill Moyers Reports, 2001, distributed by Films for the Humanities and Sciences (www.shoppbs.org) In collaboration with the World Resources Institute, Bill Moyers assesses the state of the environment in interviews with scientists from around the world (2001).

2. Scientific Methods & Values, 1999, distributed by Hawkhill Video This 35-minute program describes the history of the scientific method and explains how scientists use the technique.

3. State of the Planet: Biosphere in the Balance, 2005, produced by BBC Worldwide and distributed by Films for the Humanities and Sciences (www.worldcat.org/title/state-of-the-planet-biosphere-in-the-balance/ oclc/062074760) This video, narrated by David Attenborough, is the first in a three-part series that describes worldwide biodiversity and the human activities that are destroying it.

4. World in the Balance, 2004, produced by NOVA and distributed by WGBH/PBS (shop.wgbh.org) This video is a two-hour program that investigates social and environmental strains placed on the world due to rapidly increasing human populations.

5. Planet Earth, 2007, produced by the BBC (www.pbs.org) This series first aired on the Discovery Channel and captured the attention of very diverse viewers. The compelling footage highlights many interesting and rare species and their habitat preferences, and also projects the viewer into the future, inspiring one to ask, “What next? What will happen if these areas and creatures are not recognized and protected?”

6. Planet in Peril, 2009, produced by CNN (www.cnn.com/services/opk/planet.peril/for.html ) This documentary talks about the state of the planet from the standpoints of CNN correspondents Jeff Corwin (wildlife biology), Anderson Cooper (social perspective), and Dr. Sanjay Gupta (human medicine).

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Suggested Texts 1. People and the Land Through Time: Linking Ecology and History. Emily Russell. Yale University Press, New Haven, 1997.

For students who want an in-depth analysis of ecological issues based on human settlement patterns, this text provides valuable insights into the evolution of contemporary environmental issues. The author begins with geology, moves through disturbance features such as anthropogenic fire, and finishes with actual case studies grounded in historical ecology.

2. Overshoot: The Ecological Basis of Revolutionary Change. William R. Catton, Jr. University of Illinois Press, Chicago, 1980.

The term overshoot is used and described in your textbook. Overshoot, now several decades in print, was a validation of Garrett Hardin’s Tragedy of the Commons and Paul Ehrlich’s The Population Bomb. Overshoot skillfully unpacks the growing dependence of human culture on technologies that enabled the exploitation of more land. Sobering and well written, with chapters reviewing issues of carrying capacity, the cornucopian myth, drawdown, “cargoism,” overshoot, and crash.

Weighing the Issues Follow the Money Facts to consider: A research scientist who is dependent on external funding is also generally dependent on the successful publication of his or her results to continue to receive funding. If the funding contract includes requiring review of results prior to publication, the results may be suppressed. There are welldocumented instances of this in tobacco research in this country, although this is still contested by the tobacco companies. For a well-documented discussion of this, see Brian Martin, “Suppressing Research Data: Methods, Context, Accountability, and Responses.” Accountability in Research, Vol. 6, 333-372, 1999. During President George W. Bush’s administration, 2000–2008, a number of stories appeared documenting the editing for political purposes of internal scientific reports, particularly from the Environmental Protection Agency, by nonscientists.

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Leaving a Large Footprint Facts to consider: The science behind the ecological footprint can be found in Wackernagel and Rees’ text, Our Ecological Footprint, New Society Publishers, 1996, and a number of footprint calculators can be found online. The answers to this question are clearly rooted in values, not in science, except that the authors make a strong case for our societal inability to continue to use resources at our current rate, the richer nations being responsible for the excess use.

The Science behind the Story What Are the Lessons of Easter Island?

Observation: Although Easter Island is presently lacking large vegetation, the examination of sediment cores from lakes, ancient pollen and nut casings, and charcoal all indicate that the place once had a thriving palm forest.

Hypothesis: Human-introduced rats contributed to palm forest loss.

Results: When Polynesians settled new islands, they brought crop plants as well as chickens and other domestic animals. They also brought rats—intentionally as a food source or unintentionally as stowaways. In either case, rats multiplied quickly, and they soon overran Rapa Nui. Researchers found rat tooth marks on old nut casings, and Hunt and Lipo suggested that rats ate so many palm nuts and shoots that the trees could not regenerate. With no young trees growing, the palm went extinct once mature trees died.

The collapse of this sustainable civilization also came with the arrival of Europeans, who unwittingly brought contagious diseases to which the islanders had never been exposed. Indeed, historical journals of sequential European voyages depict a society falling into disarray as if reeling from epidemics.

Peruvian ships then began raiding Rapa Nui and taking islanders away into slavery. Foreigners acquired the land, forced the remaining people into labor, and introduced thousands of sheep, which destroyed the few native plants left on the island. Thus, the new hypothesis holds that the collapse of Rapa Nui’s civilization resulted from a barrage of disease, violence, and slave raids following foreign contact.

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Local Connections What environmental issues are people discussing on your campus or in the area where you live? Describe two sides of a debate over one of these issues. Where do you stand in this debate, and why? Describe how you think the two sides could begin to resolve their differences.

Class time required: one class period minimum, two class periods maximum

This prompt could be used as a first-day or week activity. To begin, have students (individually or in small groups) generate a list of 5–10 environmental issues they believe are relevant to your campus or local area. After 5–10 minutes, have students write their lists on the board.

There should be some issues that appear in many lists. Choose one of these issues for a short debate. You may have to modify it slightly to make it work for a debate. For example, if one of the issues is transportation to school, you might frame it as a debate over whether the school should provide students with a free bus/train pass.

You can either break the class into two groups or have students work individually to develop an argument for and against the topic. Allow them to use the Internet to research the topic for 30 minutes or more. End by holding a debate and a class discussion about how to resolve the issue.

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Calculating Ecological Footprints Nation

Ecological footprint (hectares per person)

Proportion relative to world average footprint

Proportion relative to world area available

Bangladesh

0.84

0.31 (0.84 ÷ 2.75)

0.52 (0.84 ÷ 1.63)

Tanzania

1.22

0.44

0.75

Colombia

2.05

0.75

1.26

Thailand

2.49

0.91

1.53

Mexico

2.6

0.95

1.60

Sweden

6.46

2.35

3.96

United States

8.10

2.95

4.97

World average

2.75

1 (2.75 ÷ 2.75)

1.69 (2.75 ÷ 1.63)

Your personal footprint 1. Bangladesh has a low per-capita income.

2. The United States has a high per-capita income.

3. Higher per-capita income suggests a higher consumption of goods, which require natural resources in their production. There is also a correlation between the use of energy resources, especially for transportation, and income.

Wealthier societies can decrease water consumption by reducing their demand on that resource; generate less waste by investing in more durable, reusable products; and simply purchase fewer goods.

4. Student answers will vary.

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2 Earth’s Physical Systems: Matter, Energy, and Geology Chapter Objectives This chapter will help students: Explain the fundamentals of matter and chemistry and apply them to realworld situations Differentiate among forms of energy and explain the first and second laws of thermodynamics Distinguish photosynthesis, cellular respiration, and chemosynthesis, and summarize their importance to living things Explain how plate tectonics and the rock cycle shape the landscape around us Identify major types of geological hazards, and describe ways to minimize their impacts

Lecture Outline I.

Central Case Study: What is the Legacy of the Fukushima Daiichi Nuclear Tragedy?

A. At 2:46 p.m. on March 11, 2011, a 9.0-magnitude earthquake hit the Japanese island of Honshu.

B. The damage from the earthquake was supplemented by a following tsunami.

C. A tsunami is a powerful surge of seawater generated when an offshore earthquake displaces large volumes of rocks and sediment on the ocean bottom, suddenly pushing the overlying ocean water upward.

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D. The raging water swept up to 9.6 km (6 mi) inland, scoured buildings from their foundations, and inundated towns, villages, and productive agricultural land.

E. This tsunami severely damaged the Fukushima Daiichi nuclear power plant.

F. To prevent a full-blown catastrophe that could render large portions of their nation uninhabitable, Japanese authorities flooded the reactor cores with seawater pumped in from the ocean.

G. A 20-km (12-mi) area around the Fukushima Daiichi plant has been permanently evacuated. Some of the greatest concerns center on contaminated food and water, so crops and seafood from the region will require testing for radiation for many years to come.

H. After the accident, public opposition to nuclear power in Japan ran high, and the government ordered the immediate shutdown and reinspection of its 48 nuclear reactors.

II.

Matter, Chemistry, and the Environment 1. An understanding of matter itself helps us to fully appreciate all the processes of our world.

2. All material in the universe that has mass and occupies space is called matter. Types of matter and some of the important ways they interact are called chemistry.

A. Matter is conserved.

1. Matter may be transformed from one type of substance into others, but it cannot be created or destroyed. This principle is referred to as the law of conservation of matter.

B. Elements and atoms are chemical building blocks.

1. The nuclear reactor at Fukushima Daiichi used the element uranium to power its reactors.

2. An element is a fundamental type of matter, a chemical substance with a given set of properties that cannot be broken down into substances with other properties.

3. Elements especially abundant on our planet include hydrogen, oxygen, silicon, nitrogen, and carbon.

4. The periodic table of the elements organizes the elements according to their chemical properties and behavior.

5. Atoms are the smallest units that maintain the chemical properties of the element.

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6. Atoms of each element contain a specific number of protons in the atom’s nucleus and this is called the element’s atomic number.

7. Most atoms also contain neutrons in their nuclei, and an element’s mass number denotes the combined number of protons and neutrons in the atom.

8. An atom’s nucleus is surrounded by negatively charged particles known as electrons, which balance the positive charge of the protons.

Isotopes 1. Atoms of the same element with differing numbers of neutrons are referred to as isotopes.

2. Some isotopes, called radioisotopes, are radioactive and “decay” by changing their chemical identity as they shed subatomic particles and emit high-energy radiation.

3. The greatest danger from radioisotopes occurs when they enter the bodies of organisms through the lungs, skin, or digestive system.

4. Each radioisotope decays at a rate determined by that isotope’s half-life, the amount of time it takes for one-half the atoms to give off radiation and decay.

Ions 1. Atoms may gain or lose electrons, thereby becoming ions, electrically charged atoms, or combinations of atoms.

2. The damaging radiation emitted by radioisotopes is called ionizing radiation because it generates ions when it strikes molecules.

C. Atoms bond to form molecules and compounds.

1. Atoms bond together and form molecules, combinations of two or more atoms.

2. A molecule composed of atoms of two or more different elements is called a compound. a. One compound is water, two hydrogen atoms bonded to an oxygen atom. b. Another is carbon dioxide, consisting of one carbon atom bonded to two oxygen atoms.

3. Atoms bond together because of an attraction for one another’s electrons. a. When electrons are shared between atoms, a covalent bond forms.

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b. When an arrangement allows water molecules to adhere to one another in a type of weakly attractive interaction, this is called a hydrogen bond. c. In compounds in which strength of attraction is sufficiently unequal, an electron may be transferred from one atom to another. This creates oppositely charged ions that form ionic bonds.

4. Elements, molecules, and compounds can also come together in mixtures without chemically bonding or reacting.

D. Matter is composed of organic and inorganic compounds.

1. Organic compounds consist of carbon atoms joined by covalent bonds.

2. One class of organic compounds that is important in environmental science is the hydrocarbons, which consists solely of bonded atoms of carbon and hydrogen.

3. Some hydrocarbons from petroleum have become ubiquitous in our modern lifestyle because they are moldable into nearly any shape and resist chemical breakdown. Although these plastics have many benefits for consumer products, they can be a persistent source of pollution because of their longevity in the environment.

E. Macromolecules are building blocks of life.

1. Organic compounds sometimes combine to form long chains of repeated molecules. These chains are called polymers. There are three types of polymers that are essential to life: proteins, nucleic acids, and carbohydrates. Along with lipids (which are not polymers), these types of molecules are referred to as macromolecules because of their large sizes.

2. Proteins consist of long chains of organic molecules called amino acids. Some produce tissues and provide structural support; others provide energy storage and immune system functions. Still others are hormones or chemical reaction catalysts called enzymes.

3. Nucleic acids direct the production of proteins. Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) carry the hereditary information for organisms. Nucleic acids are composed of nucleotides, each of which contains a sugar molecule, a phosphate group, and a nitrogenous base. Regions of DNA coding for particular proteins that serve particular functions are called genes.

4. Carbohydrates include simple sugars that are 3–7 carbon atoms long. Glucose fuels living cells and serves as a building block for complex carbohydrates. Complex carbohydrates include starch, an 20 ..

energy storage compound; chitin, a structural component of shells; and cellulose, the most abundant organic compound on Earth, found in the cell walls of plants.

5. Lipids include fats and oils (for energy storage), phospholipids (for cell membranes), waxes (for structure), and steroids (for hormone production). Although chemically diverse, these compounds are grouped together because they do not dissolve in water.

F. Hydrogen ions determine acidity.

1. In any aqueous solution, a small number of water molecules split apart, each forming a hydrogen ion (H+) and a hydroxide ion (OH–). a. Solutions in which the H+ concentration is greater than the OH– concentration are acidic. b. The reverse case creates solutions that are basic, or alkaline.

2. The pH scale quantifies the acidity or alkalinity of solutions. a. A pH less than 7 indicates an acidic solution. b. A pH greater than 7 indicates a basic solution. c. Pure water has a pH of 7. d. The pH scale is logarithmic; each step represents a tenfold difference in hydrogen ion concentration.

3. Most biological systems have a pH between 6 and 8.

III.

Energy: An Introduction 1. Energy is the capacity to change the position, physical composition, or temperature of matter—in other words, a force that can accomplish work.

A. Energy comes in different forms.

1. Two major forms of energy that scientists commonly distinguish are potential energy, the energy of position or composition, and kinetic energy, the energy of motion.

2. Chemical energy is essentially potential energy stored in the bonds among atoms. Converting molecules with high-energy bonds into molecules with lower-energy bonds releases energy, producing motion, action, or heat.

3. Nuclear energy, the energy that holds atomic nuclei together, and mechanical energy, such as that stored in a compressed spring, are other types of potential energy.

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B. Energy is always conserved, but it changes in quality.

1. The first law of thermodynamics states that energy can change from one form to another, but cannot be created or destroyed.

2. The second law of thermodynamics states that the nature of energy will change from a more-ordered state to a less-ordered state, as long as no force counteracts this tendency. Systems tend to move toward increasing disorder, or entropy.

3. The order of an object or system can be increased by the input of energy from outside the system.

C. Light energy from the sun powers our planet.

1. The energy that powers the Earth’s biological systems comes primarily from the sun.

2. Some organisms use the sun’s radiation directly to produce their own food. Such organisms, called autotrophs or primary producers, include green plants, algae, and cyanobacteria. In the process of photosynthesis, autotrophs use sunlight to power a series of chemical reactions that transforms molecules with lower-energy bonds—water and carbon dioxide—into sugar molecules with many high-energy bonds.

D. Photosynthesis produces food for plants and animals.

1. Photosynthesis occurs within cell organelles called chloroplasts, where the light-absorbing pigment chlorophyll uses solar energy to initiate a series of chemical reactions. a. In a series of chemical reactions called light reactions, photosynthesis uses solar energy to split water molecules to form hydrogen ions and the oxygen we breathe. b. The light reactions produce high-energy molecules that fuel reactions in the Calvin cycle where sugars are formed.

2. The net process of photosynthesis is defined by the chemical equation: 6CO2 + 6H2O + the sun’s energy → C6H12O6 (sugar) + 6O2 3. Animals depend on the sugars and oxygen from photosynthesis.

E. Cellular respiration powers living things.

1. Organisms make use of the chemical energy created by photosynthesis in a process called cellular respiration, which is vital to life.

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2. The net equation for cellular respiration is the exact opposite of that for photosynthesis: C6H12O6 (sugar) + 6O2 → 6CO2 + 6H2O + energy 3. Cellular respiration occurs in all living things—in both the autotrophs that create glucose and in heterotrophs, organisms that gain their energy by feeding on other organisms.

F. Geothermal energy also powers Earth’s systems.

1. Although the sun is life’s primary energy source, it is not the only source of energy for our planet. An additional, although minor, energy source is the gravitational pull of the moon, which in conjunction with the sun’s gravitational pull causes ocean tides.

Another significant energy source is geothermal heating emanating from inside Earth, powered primarily by radioactivity.

2. Geothermal energy also powers biological communities. On the ocean floor, jets of geothermally heated water gush into the icycold depths. These hydrothermal vents can host entire communities of specialized organisms that thrive in the extreme high-temperature, high-pressure conditions.

3. Bacteria in deep-sea vents use the chemical-bond energy of hydrogen sulfide (H2S) to transform inorganic carbon into organic carbon compounds in a process called chemosynthesis, defined by the following equation: 6CO2 + 6H2O + 3H2S → C6H12O6 (sugar) + 3H2SO4 4. Chemosynthesis closely resembles the photosynthesis reaction.

IV.

Geology: The Physical Basis for Environmental Science 1. A good way to understand how our planet functions is to examine the rocks, soil, and sediments beneath our feet.

2. Understanding the physical nature of our planet also benefits our society.

3. Our planet is dynamic and this dynamism is what motivates geology, the study of Earth’s physical features, processes, and history. We can begin to grasp this long-term dynamism as we consider two processes of fundamental importance—plate tectonics and the rock cycle.

A. Earth consists of layers.

1. Our planet consists of multiple layers. a. Earth’s center is a dense core consisting mostly of iron, solid in the inner core and molten in the outer core.

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b. Surrounding the core is a thick layer of less dense, elastic rock called the mantle. c. A portion of the upper mantle called the asthenosphere contains especially soft rock, melted in some areas. d. Above that is the harder rock we know as the lithosphere. e. The lithosphere includes Earth’s crust, the thin, brittle, lowdensity layer of rock that covers the surface. f. The heat from the inner layers of Earth also drives convection currents that move mantle material. As this material moves, it drags lithospheric plates along the surface. This movement is known as plate tectonics.

B. Plate tectonics shapes Earth’s geography.

1. Our planet’s surface consists of about 15 major tectonic plates that move at rates of roughly 2–15 cm per year. The plates’ movement has influenced Earth’s climate and life’s evolution.

C. There are three types of plate boundaries.

1. The processes that occur at each type of plate boundary all have major consequences.

2. At divergent plate boundaries, tectonic plates push apart from one another as magma rises upward to the surface, creating new lithosphere as it cools.

3. Where two plates meet, they may slip and grind alongside one another, forming a transform plate boundary. Faults are fractures in Earth’s crust.

4. Convergent plate boundaries, where two plates come together, can give rise to different outcomes. a. One plate may slide beneath the other in a process called subduction. b. When two plates of continental lithosphere meet, the continental crust on both sides resists subduction and instead crushes together, bending, buckling, and deforming layers of rock from both plates in a continental collision.

D. Tectonics produces Earth’s landforms.

1. Tectonic movements build mountains; shape the geography of oceans, islands, and continents; and give rise to earthquakes and volcanoes.

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2. The topography created by tectonic processes, in turn, shapes climate by altering patterns of rainfall, wind, ocean currents, and heating and cooling—all of which affect rates of weathering and erosion and the ability of plants and animals to inhabit different regions.

E. The rock cycle produces a diversity of rock types.

1. Over geological time, rocks and the minerals that make them up are heated, melted, cooled, broken down, and reassembled in a very slow process called the rock cycle.

2. A rock is any solid aggregation of minerals. A mineral is any naturally occurring solid element or inorganic compound with a crystal structure, a specific chemical composition, and distinct physical properties.

Igneous rock 1. If magma is released through the lithosphere, it may flow or splatter across Earth’s surface as lava. Rock that forms when lava cools is called igneous rock.

2. Igneous rock comes in two main classes because magma can solidify in different ways.

Sedimentary rock 1. Through weathering and erosion, particles of rock blown by wind or washed away by water come to rest downhill, downstream, or downwind from their sources, eventually forming sediments.

2. Sedimentary rock is formed as sediments are physically pressed together and as dissolved minerals seep through sediments and act as a kind of glue, binding sediment particles together. The formation of rock through these processes is termed lithification.

3. These processes also create the fossils of organisms and the fossil fuels we use for energy.

Metamorphic rock 1. When any type of rock is subjected to great heat or pressure, it may alter its form, becoming metamorphic rock.

F. Geological processes occur across “deep time.”

V.

Geological and Natural Hazards 1. Although plate tectonics have shaped our planet, some tectonic movement can also pose hazards to us.

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A. Earthquakes result from movement at plate boundaries and faults.

1. Along tectonic plate boundaries, Earth may relieve built-up pressure in fits and starts. Each release of energy causes what we know as an earthquake.

2. To minimize damage from earthquakes, engineers have developed ways to protect buildings from shaking.

3. Such quake-resistant designs are more expensive to build than conventional designs, so many buildings in poorer nations do not have such protections.

B. Volcanoes arise from rifts, subduction zones, or hotspots.

1. Where molten rock, hot gas, or ash erupts through Earth’s surface, a volcano is formed, often creating a mountain over time as cooled lava accumulates.

2. Lava may also be emitted at hotspots, localized areas where plugs of molten rock from the mantle erupt through the crust.

3. Volcanic eruptions affect people as well as the environment.

4. One of the world’s largest volcanoes—so large it is called a supervolcano—lies in the United States.

C. Landslides are a form of mass wasting.

1. A landslide occurs when large amounts of rock or soil collapse and flow downhill. Landslides are a severe and sudden manifestation of mass wasting, the downslope movement of soil and rock due to gravity.

D. Tsunamis can follow earthquakes, volcanoes, or landslides.

1. Earthquakes, volcanic eruptions, and large coastal landslides can all displace huge volumes of ocean water instantaneously and trigger a tsunami.

2. Residents of the United States and Canada are vulnerable to tsunamis as well.

3. One of the best protections against tsunamis is advance warning.

E. We can worsen or lessen the impacts of natural hazards.

1. Flooding, coastal erosion, wildfire, tornadoes, and hurricanes are “natural hazards” whose impacts can be worsened by the choices that we make. a. We live in areas that are prone to hazards, such as the floodplains of rivers or in coastal areas susceptible to flooding.

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b. People also use and engineer landscapes around us in ways that can increase the frequency or severity of natural hazards. c. Damming and diking rivers to control floods can sometimes lead to catastrophic flooding, and the clearcutting of forests on slopes can induce mass wasting and increase water runoff. d. Human-induced climate change can cause sea levels to rise and promote coastal flooding and can increase the risks of drought, fire, flooding, and mudslides by altering precipitation patterns.

2. We can reduce or lessen the impacts of hazards through the thoughtful use of technology, engineering, and policy, informed by a solid understanding of geology and ecology.

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Key Terms acidic asthenosphere atoms autotrophs basic bioremediation carbohydrates carbon carbon dioxide cellular respiration chemistry chemosynthesis compound continental collision convergent plate boundaries core covalent bond crust deoxyribonucleic acid (DNA) divergent plate boundaries earthquake electrons element energy energy conversion efficiency first law of thermodynamics genes geology half-life heterotrophs hydrocarbons hydrogen hydrogen bond hydrothermal vents igneous rock

ionic bonds ionizing radiation ions isotopes kinetic energy landslide lava law of conservation of matter lipids lithosphere macromolecules magma mantle mass wasting matter metamorphic rock mineral molecules neutrons nitrogen nucleic acids nutrients organic compounds oxygen pH photosynthesis plastics plate tectonics polymers potential energy primary producers proteins protons radioactive radioisotope

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ribonucleic acid (RNA) rock rock cycle second law of thermodynamics sedimentary rock sediments silicon

subduction transform plate boundary tsunami uranium volcano water work

Teaching Tips 1. Ask students to generate a list of environmental problems and write them on the board. As a group, analyze each problem to determine how chemistry is involved in understanding it. For example, smog is the result of the chemical reaction of nitrogen oxides and hydrocarbons in the presence of sunlight.

Allow students to use the textbook if they need more information.

2. Ask students to consider the ways in which they utilize kinetic energy each day. Then ask them to describe the potential energy source that was converted.

3. Ask students to describe what the consequences to the environment would be if water did not become less dense upon freezing.

4. The 2010 fire and explosion on an oil-drilling rig in the Gulf of Mexico, and the subsequent leakage of oil into the environment, has had far-reaching consequences. Ask students to search the Internet for information on the fate of various components of the crude oil, that is, how the molecular weight of the hydrocarbons affected the deposition, transport, and treatment of components.

Examine the issue that arose with methane hydrates during the attempt to stop the flow. Ask students to compare this situation with that of the 1989 Exxon Valdez oil spill in Prince William Sound.

5. In this chapter, DNA and RNA are described. Recent scientific research on DNA has centered on genetic engineering and cloning. Lead a discussion about the pros and cons of these issues.

6. The ecological footprint exercise in this chapter leads into a more complex discussion in later chapters. Explore with the students why energy considerations might be important in this regard while also keeping in mind the first and second laws of thermodynamics.

7. Community service: Have the students explore potential natural hazards in their communities: Is there sufficient information being provided to residents regarding these? Could students propose ways to improve the dissemination of such information?

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Additional Resources Websites 1. Office of Response and Restoration, Oceanic Service, NOAA (response.restoration.noaa.gov) This website is the gateway to the NOAA department that is involved in oceanic environmental disasters, including the Exxon Valdez oil spill in Prince William Sound.

2. General Chemistry Online!, Frostburg State University (antoine.frostburg.edu/chem/senese/101/index.shtml) This web resource is an interactive guide for students and teachers of introductory college chemistry.

3. Vents Program, Pacific Marine Environmental Laboratory, NOAA (www.pmel.noaa.gov/vents) The Vents Program website provides information about submarine volcanoes and hydrothermal venting.

4. NOAA Watch, NOAA’s All Hazard Monitor (http://www.weather.gov/briefing) As the title implies, this is a website that provides current information on all natural hazards worldwide, including earthquakes, volcanoes, severe weather, and drought.

5. Latest Earthquakes in the World, US Geological Survey (earthquake.usgs.gov/earthquakes/map) This website is a wonderful online resource for the classroom, providing visual data on the latest earthquakes worldwide. It is capable of zooming in to very local areas. Like the previous item, the parent site also has a lot of visual information on the larger class of natural hazards.

Audiovisual Materials 1. Origins, 2004, NOVA, produced by Thomas Levenson and distributed by PBS (www.pbs.org/wgbh/nova/space/origins-series-overview.html) Neil deGrasse Tyson narrates this four-part series that explores the origins of the universe, Earth, and life. The program is available in VHS and DVD formats and comes with a companion book.

2. Volcanoes of the Deep Sea, 2003, produced by Stephen Low and distributed by Discovery Channel (www.amazon.com/Volcanoes-Deep-Sea-IMAXHarris/dp/B0007WFY5W)

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This 90-minute film depicts a team of scientists as they explore an incredible world teeming with life 12,000 feet beneath the ocean surface. This prizewinning documentary was originally created for exhibition in IMAX theaters and is available only on DVD. 3. Natural Hazards Video Gallery, US Geological Survey (gallery.usgs.gov/video_collections/Natural_Hazards) This is a very large collection of short video clips on a wide range of natural disasters.

Weighing the Issues Assessing Your Risk from Natural Hazards Facts to consider: A useful website for beginning this discussion is: earthobservatory.nasa.gov/topic/natural-event You can find information on nearly every possible natural hazard for locations throughout the world on this website. The importance of science in the decision of rebuilding is often diminished by cultural and economic considerations.

The Science behind the Story Are Yeasts the Answer to Cleaning up Nuclear Waste?

Observation: The Hanford Nuclear Reservation in Washington has been leaking radioactive waste since 1959. An estimated 3 trillion liters of surface and ground water and 70 million cubic meters of soil is now thought to be contaminated.

Physically removing the contaminated soil and water is neither safe nor economically feasible. Scientists are instead considering using bioremediation whereby microorganisms clean the site as an alternative.

Study: Michael Daly and his team collected yeast samples from 60 different extreme environments. The team found 27 different types of yeast in the samples.

The team screened the 27 types for their tolerance to extreme conditions that are present in radioactive waste including ionizing radiation, acidity, temperature, and toxic heavy metals.

Result: The team identified one strain of the yeast Rhodotorula taiwanensis that tolerated high levels of radioactivity, elevated concentrations of toxic heavy metals, and low pH. However, R. taiwanensis was not a perfect fit because its growth rate decreases as temperature increases, as would be the case beneath a leaking nuclear waste tank. This research illustrates the possibility of using a mixture of microorganisms, with specific tolerances, to clean up nuclear waste.

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Are the Earthquakes Rattling Oklahoma Caused by Human Activity?

Question: Is the injection of wastewater from oil and gas extraction into porous rock layers beneath the state causing increased earthquake activity in Oklahoma?

Evidence: Wastewater had been injected in this manner beneath Oklahoma for decades without any measurable increase in seismic activity, but scientists were aware that continued pumping of wastewater into rock formations could lead to earthquakes. As the pores within rocks become saturated with water, pressure grows in the underground rock layers, causing the rocks to expand. These expanding rock layers then push against existing faults in the earth, which “lubricates” them and causes them to slip and produce earthquakes. The rock formations beneath Oklahoma facilitate this process because many of the porous layers of limestone into which wastewaters are injected are located near stressed rocks around faults.

A study led by geophysicist Katie Keranen of the University of Oklahoma (now at Cornell University) and published in the journal Geology measured the aftershocks produced by the earthquake to determine the location of the fault that produced the quake. The researchers deployed seismic sensors near Prague within 24 hours of the initial quake and gathered detailed readings on two major tremors and 1,183 aftershocks that followed. An analysis of the patterns revealed that the tip of the fault that ruptured was within about 200 m (650 ft) of an active wastewater injection well and occurred at depths consistent with injected rock layers. Keranen’s work also showed that it is possible for nearly two decades to pass between the initiation of wastewater injection and a subsequent seismic event, calling into question the safety of many other injection sites. A subsequent study led by Keranen found that earthquakes could be induced as far as 30 km (19 mi) from injection well fields, and concluded that up to 20% of the induced seismic activity over an area covering 2000 km2 (770 mi2) in the central United States could be traced to the activity of four high-volume wastewater disposal wells in Oklahoma.

Local Connections Nuclear power has both risks and benefits, and people’s opinions on its use can differ greatly. Informally interview at least ten people—friends, family members, or classmates—and ask them their view on the role that nuclear power should play in future U.S. energy production. Should we increase our nation’s use of nuclear power, reduce it, or ban it completely? Do people’s opinions change if a new nuclear power plant is slated to be placed in their area?

Class time required: 30 minutes (15 minutes to generate questions, 15 minutes to discuss results)

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Most of the time students spend on this activity will be outside of class, but it is important to support students before they begin their interviews. Have the students (individually or in small groups) generate a list of five interview questions related to nuclear power. Have students share their lists with the class. Allow time for discussion related to the questions. At the end, allow time for students to finalize their list of questions. You may allow students to each have their own list of questions or you may want to have all students ask the same questions.

Be sure to have a short discussion about how to conduct an interview. The students themselves will most likely have strong opinions about nuclear power. Remind them that as an interviewer, it is important to be impartial, to ensure that they don’t influence the person they are interviewing. This could also be an excellent place to have a discussion about sources of information and reliability of information. See the list below for activities about evaluating the credibility of sources.

Give students a week to conduct their interviews. Once students have conducted their interviews, allow them a chance to discuss their findings in small groups or as a class.

Activities Related to Evaluating the Credibility of Sources 1. The Annenberg Classroom—The Credibility Challenge www.annenbergclassroom.org/resource/the-credibility-challenge/

2. The New York Times—Evaluating Sources in a ‘“Post-Truth’” World: Ideas for Teaching and Learning About Fake News www.nytimes.com/2017/01/19/learning/lesson-plans/evaluating-sourcesin-a-post-truth-world-ideas-for-teaching-and-learning-about-fakenews.html

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Calculating Ecological Footprints Source of calories

Diet

100% plant 0% animal 90% plant

Plant Animal Plant

Number of calories consumed 2,000 0

10% animal

Animal

90%  2,000 = 1,800 200

50% plant 50% animal 70% plant 30% animal 0% plant 100% animal

Plant Animal Plant Animal Plant Animal

1,000 1,000 1400 600 0 2,000

Ecologically equivalent calories 2,000 0 1,800 200  10 = 2,000 1,000 10,000 1400 6000 0 20,000

Total ecologically equivalent calories 2,000 1,800 + 2,000 = 3,800 11,000 5600 20,000

1. Multiply the total ecologically equivalent calories per day by 365 days per year: 730,000 calories; 1,387,000 calories; 4,015,000 calories; 2,044,000 calories; and 7,300,000 calories, respectively.

2. A diet of only animal food has ten times the ecological impact of a strictly vegetarian diet (20,000 ecologically equivalent calories per day versus 2,000).

Taking just 10% of one’s diet from animal sources means consuming an additional 1,800 ecologically equivalent calories beyond those of a strictly vegetarian diet.

3. Answers will vary.

4. Answers will vary.

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3 Evolution and Population Ecology Chapter Objectives This chapter will help students: Explain natural selection and cite evidence for this process Describe how evolution generates and shapes biodiversity Discuss factors behind species extinction and identify Earth’s known mass extinction events List the levels of ecological organization Describe attributes of populations that help predict population growth Explain the roles that logistic growth, limiting factors, carrying capacity, and other fundamental concepts play in population ecology Identify and discuss challenges and current efforts in conserving biodiversity

Lecture Outline I.

Central Case Study: Saving Hawaii’s Native Forest Birds A. Half of Hawaii’s native bird species (95 of 142) have gone extinct in recent times, and many of those that remain—like the aki—teeter on the brink of extinction.

B. The aki is a type of Hawaiian honeycreeper, a group of 18 living species (and at least 38 species recently extinct), all of which originated from individuals of a single ancestral species that reached Hawaii several million years ago.

C. Hawaii’s honeycreepers thrived for several million years in the island’s forests, amid a unique community of plants found nowhere else in the world.

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D. Today, these native Hawaiian forests are under siege.

E. Newly introduced organisms wreaked havoc because native Hawaiian organisms were unprepared to resist them.

F. With the arrival of people, domestic animals, and invasive plants also came diseases.

G. Today, few native forest birds exist anywhere on the Hawaiian Islands below 1500 m (4500 ft) in elevation.

H. Conservation biologists and managers have worked hard to keep the Hakalau Forest protected. Young restored native forest is now regrowing on thousands of acres. More birds are using this restored forest every year.

I. Today, global climate change is presenting new challenges.

J. Plenty of challenges remain, but the restoration successes at Hakalau Forest so far provide hope that through responsible management we can restore Hawaii’s native flora and fauna, prevent further impacts, and preserve the priceless bounty of millions of years of evolution on this extraordinary chain of islands.

II.

Evolution: The Source of Earth’s Biodiversity 1. A species is a particular type of organism or, more precisely, a population or group of populations whose members share characteristics and can freely breed with one another and produce fertile offspring.

2. A population is a group of individuals of a given species that live in a particular region at a particular time.

3. Evolution in the broad sense means change over time, and biological evolution consists of change in populations of organisms from generation to generation.

A. Natural selection shapes organisms.

1. Natural selection is the process by which inherited characteristics that enhance survival and reproduction are passed on more frequently to future generations than characteristics that do not, thereby altering the genetic makeup of populations through time.

2. The idea of natural selection follows logically from a few straightforward facts that are readily apparent to anyone who observes the life around us.

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a. Organisms face a constant struggle to survive and reproduce. b. Organisms tend to produce more offspring than can survive to maturity. c. Individuals of a species vary in their attributes.

3. Variation is due to differences in genes, the environments in which genes are expressed, and the interactions between genes and environment. As a result of this variation, some individuals of a species will be better suited to their environment than others and so will survive longer and will be better able to reproduce.

4. From one generation to another through time, characteristics, or traits, that lead to better reproductive success in a given environment will evolve in the population. This is termed adaptation, and a trait that promotes success is also called an adaptation or an adaptive trait.

5. The concept of natural selection was first proposed in the 1850s by Charles Darwin and, independently, by Alfred Russel Wallace, two exceptionally keen British naturalists.

B. Understanding evolution is vital for modern society.

1. Many medical advances have resulted from our knowledge of evolution.

2. In agriculture, our understanding of evolution helps us to prevent antibiotic resistance in feedlots and pesticide resistance in cropeating insects.

C. Selection acts on genetic variation.

1. Accidental changes in DNA, called mutations, give rise to genetic variation among individuals.

2. Genetic variation is also generated as organisms mix their genetic material through sexual reproduction.

3. Because evolutionary change generally requires a great deal of time, a species cannot always adapt to environmental conditions that change quickly.

4. However, genetic variation can sometimes help protect a population against novel challenges.

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D. Selective pressures from the environment influence adaptation.

1. Closely related species that live in very different environments tend to diverge in their traits because differing selective pressures drive the evolution of different adaptations. Conversely, sometimes very unrelated species living in similar environments in separate locations may independently acquire similar traits as they adapt to similar selective pressures; this is called convergent evolution.

2. Environments change over time and traits that produce success at one time or place may not do so at another.

E. Evidence of selection is all around us.

1. Scientists have demonstrated the rapid evolution of traits by selection in countless lab experiments, mostly with fastreproducing organisms such as bacteria, yeast, and fruit flies.

2. The process of selection conducted under human direction is termed artificial selection.

3. Through selective breeding, we have been able to augment particular traits we prefer.

4. Many of our domestic pets and food crops are a result of this process.

F. Evolution generates biological diversity.

1. Biological diversity, or biodiversity, refers to the variety of life across all levels, including the diversity of species, genes, populations, and communities.

2. Scientists have identified and described about 1.8 million species but estimate that 100 million may exist.

G. Speciation produces new types of organisms.

1. The process by which new species are generated is termed speciation. The main mode is generally thought to be allopatric speciation, whereby species form from populations that become physically separated over some geographic distance.

2. When a mutation arises in the DNA of an organism in one of these newly isolated populations, it cannot spread to the other populations.

3. Populations can undergo long-term geographic isolation in various ways.

4. Alternatively, sometimes organisms colonize newly created areas, establishing isolated populations.

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H. We can infer the history of life’s diversification by comparing organisms.

1. Scientists represent the history of divergence by using branching, treelike diagrams called phylogenetic trees.

2. Once we have a phylogenetic tree, we can map traits onto the tree according to which organisms possess them, and we can thereby trace how the traits have evolved.

3. Taxonomists use an organism’s genetic makeup and physical appearance to determine its species identity. Related species are grouped together into genera (singular, genus), related genera are grouped into families, and so on.

4. Today, biologists use evolutionary information from phylogenetic trees to help classify organisms under the Linnaean system’s rules.

I. Fossils reveal life’s long history.

1. As organisms die, some are buried by sediment. Hard parts of their bodies—such as bones, shells, and teeth—may be preserved, as sediments are compressed into rock. Minerals replace the organic material, leaving behind a fossil, an imprint in stone of the dead organism. The cumulative body of fossils worldwide is known as the fossil record.

2. The fossil record shows that the number of species existing at any one time has generally increased, but that the species on Earth today are just a small fraction of all species that have ever existed.

During life’s 3.5 billion years on Earth, complex structures have evolved from simple ones, and large sizes from small ones.

3. The disappearance of a species from Earth is called extinction.

4. Extinction occurs naturally, but human impact can profoundly affect the rate at which it occurs.

J. Some species are especially vulnerable to extinction.

1. Small populations are vulnerable to extinction because fluctuations in their size could, by chance, bring the population size to zero.

Species narrowly specialized to some particular resource or way of life are also vulnerable because environmental changes that make that resource or role unavailable can spell doom. Species that are endemic to a region, meaning that they occur nowhere else on the planet, also face elevated risks of extinction because when an event influences their region, it may affect all members of the species.

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2. Island-dwelling species are frequently vulnerable.

3. On a mainland, “islands” of habitat can host endemic species that are vulnerable to extinction.

K. Earth has seen several episodes of mass extinction.

1. Most extinction occurs gradually, one species at a time, at a rate referred to as the background extinction rate. However, the fossil record reveals that Earth has seen at least five events of staggering proportions that killed off massive numbers of species at once.

These episodes, called mass extinction events, have occurred at widely spaced intervals in our planet’s history and have wiped out 50% to 95% of Earth’s species each time.

2. The best-known mass extinction occurred 66 million years ago and brought an end to the dinosaurs.

L. The sixth mass extinction is upon us.

1. The Millennium Ecosystem Assessment estimated that today’s extinction rate is 100 to 1,000 times higher than the background rate, and rising.

III.

Ecology and the Organism 1. Ecology is the scientific study of the interactions among organisms and of the relationships between organisms and their environments.

A. We study ecology at several levels.

1. Life exists in a hierarchy of levels, from atoms, molecules, and cells up through the biosphere, which is the cumulative total of living things on Earth and the areas they inhabit. Ecologists are scientists who study relationships at the higher levels of this hierarchy, namely at the levels of the organism, population, community, ecosystem, landscape, and biosphere.

2. At the level of the organism, ecology describes the relationships between an organism and its physical environment. In contrast, population ecology examines the dynamics of population change and the factors that affect the distribution and abundance of members of a population.

3. A community consists of an assemblage of populations of interacting species that inhabits the same area. Community ecology focuses on patterns of species diversity and on interactions among species, ranging from one-to-one interactions to complex interrelationships involving the entire community.

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4. Ecosystems encompass communities and the abiotic (nonliving) material, and forces with which community members interact.

Ecosystem ecology addresses the flow of energy and nutrients by studying living and nonliving components of systems in conjunction.

5. Landscape ecology helps us understand how and why ecosystems, communities, and populations are distributed across geographic regions.

B. Each organism has habitat needs.

1. The specific environment in which an organism lives is its habitat.

2. Each organism thrives in certain habitats and not others, leading to nonrandom patterns of habitat use. Mobile organisms actively select habitats in which to live from among the range of options they encounter, a process called habitat selection.

3. Habitats are scale dependent.

4. The criteria by which organisms favor some habitats over others can vary greatly.

5. Because habitats provide everything an organism needs, including nutrition, shelter, breeding sites, and mates, the organism’s very survival depends on the availability of suitable habitats.

C. Organisms play roles in communities.

1. A species’ niche is its functional role in a community.

2. Species with narrow breadth, and thus very specific requirements, are said to be specialists. Those with broad tolerances, able to use a wide array of resources, are generalists.

3. Specialists succeed over evolutionary time by being extremely good at the things they do, but they are vulnerable when conditions change and threaten the habitat or resource on which they have specialized. Generalists succeed by being able to live in many different places and withstand variable conditions, yet they do not thrive in any single situation as well as a specialist adapted for those specific conditions.

IV.

Population Ecology A. Populations show features that help predict their dynamics.

1. Population size is expressed as the number of individual organisms present at a given time, and may increase, decrease, undergo cyclical change, or remain stable.

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2. Population density describes the number of individuals per unit area in a population.

3. Population distribution describes the spatial arrangement of organisms in an area. a. In a random distribution, individuals are located haphazardly in no particular pattern. b. A uniform distribution is one in which individuals are evenly spaced. c. A clumped distribution often results when organisms seek habitats or resources that are unevenly spaced.

4. A population’s sex ratio is its proportion of males to females.

5. Age structure describes the relative numbers of individuals of different ages within a population.

B. Populations may grow, shrink, or remain stable.

1. Demographers, scientists who study human populations, use mathematical concepts to study population changes.

2. Population change is determined by four factors: births (natality), deaths (mortality), immigration into a population, and emigration away from a population.

3. The rate of natural increase is determined by subtracting the death rate from the birth rate.

4. The population growth rate equals the birth rate plus the immigration rate, minus the death rate plus the emigration rate.

C. Unregulated populations increase by exponential growth.

1. When a population increases by a fixed percentage each year, it is said to undergo exponential growth. A J-shaped curve shows this type of growth.

2. Populations increase exponentially unless they are constrained.

3. Normally, exponential growth occurs in nature only when a population is small, competition is minimal, and environmental conditions are ideal for the organism in question.

D. Limiting factors restrain growth.

1. Every population is eventually constrained by limiting factors— physical, chemical, and biological attributes of the environment that restrain population growth. These limiting factors determine the carrying capacity, the maximum population size of a species that a given environment can sustain.

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2. Ecologists use an S-shaped curve to show how an initial exponential increase is slowed and eventually brought to a standstill by limiting factors. This phenomenon is called logistic growth.

3. Many factors influence a population’s growth rate and carrying capacity.

E. The influence of some factors depends on population density.

1. Limiting factors are said to be density dependent when their influence rises and falls with population density.

2. Density-independent factors are those whose influence is independent of population density.

3. The logistic curve is a simplified model, and real populations in nature can behave differently.

F. Carrying capacities can change.

G. Life history strategies vary among species.

1. Population ecology, organismal ecology, and evolution all come together in life history theory, a scientific approach that explains how natural selection influences patterns of reproduction, survival, and life span.

2. In a Type I survivorship curve, survival rates are high when organisms are young and decrease sharply when organisms are old.

In a Type II survivorship curve, survival rates are equivalent regardless of an organism’s age. In a Type III survivorship curve, most mortality takes place at young ages, and survival rates are greater at older ages.

3. Population sizes of r-selected species fluctuate greatly, such that they are often well below carrying capacity. This is why natural selection in these species favors traits that lead to rapid population growth.

4. Other species are said to be K-selected (because their populations tend to stabilize near carrying capacity, commonly abbreviated K).

5. It is important to note, however, that these are two extremes on a continuum and that most species fall somewhere between the extremes of r-selected and K-selected species.

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V.

Conserving Biodiversity A. Introduced species pose challenges.

B. Innovative solutions are working.

1. Wildlife and natural areas draw visitors from around the world, a phenomenon called ecotourism.

C. Climate change poses an extra challenge.

Key Terms adaptation age structure artificial selection background extinction rate biodiversity biological diversity biosphere carrying capacity community community ecology convergent evolution Darwin, Charles demographers density dependent density independent ecologists ecology ecosystem ecology ecosystems ecotourism endemic evolution exponential growth extinction fossil fossil record

generalist habitat habitat use habitat selection landscape ecology life history theory limiting factors logistic growth mass extinction events mutations natural selection niche phylogenetic trees population population density population distribution population ecology population growth rate population size rate of natural increase sex ratio specialist speciation species Wallace, Alfred Russell

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Teaching Tips 1. It is very difficult to understand the vastness of geological time. To gain a better appreciation for Earth’s history, assign students to design a geological time scale analogy. In this exercise, students compare the biogeological history of Earth with something measurable in time, length, weight, or distance. For example, Earth’s history could be compared to a meter stick. Calculations are made to determine at what points along the meter stick major events in Earth’s biogeological history took place.

Years before Present

Major Event/Position on Meter Stick

4,600,000,000

Origin of Earth/0 cm

3,500,000,000

Life evolves/23.91 cm

458,000,000

First land plants/90.04 cm

375,000,000

Amphibians evolve/1.852 cm

200,000,000

First mammals/95.65 cm

65,000,000

Dinosaurs go extinct/98.59 cm

60,000,000

First birds/98.70 cm

100,000

Homo sapiens appears in the fossil record/99.99 cm

(One of the most misunderstood concepts among the general public is that dinosaurs and human beings did not coexist.)

2. Before covering the content of the human population chapter, have students apply these population ecology terms and concepts to the human population— for example, how do humans appear in a random distribution? Or, what type of survivorship curve applies to human beings, and why? This will prepare them for the demographic concepts in that future chapter and will get across the point that humans are animals, just one organism of many.

3. Get students active in any size class with a “Think-Pair-Share” activity, first developed by Professor Frank Lyman at the University of Maryland in 1981.

First, ask each student to consider a local environment (a forest, grassland, desert, seashore, or other nearby natural locale). Next, ask them to list two or three populations within the community and to describe some biotic and abiotic components of the ecosystem. Then have them use concepts and terms from the text—the population distribution, possible density-dependent and density-independent limiting factors, etc.—on the populations they have listed, and whether these organisms are r- or K-selected.

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After two minutes, ask each student to pair with another student nearby and share their lists and descriptions. After two more minutes, ask one or two groups to share aloud. This is an excellent method to check for student understanding of a concept and to get them actively involved with the material.

Try this before a lecture as review or in preparation for the lecture, in the middle of a lecture to ensure all students are grasping the elements of a particular topic, or at the end of a lecture as a summary technique.

Additional Resources Websites 1. Speciation and Biodiversity: Interview with Edward O. Wilson, Ph.D., 2002, Action Bioscience (www.actionbioscience.org/biodiversity/wilson.html) An interview with Dr. Wilson, a world-renowned expert on biodiversity, is provided on this website. Links to other websites are also included.

2. Evolution: Species and Speciation, 2003, University of Wisconsin Board of Regents (ats.doit.wisc.edu/biology/ev/sp/sp.htm) This activity looks at allopatric speciation and phylogenetic trees in hypothetical frog populations on an island environment.

3. Evolution, 2001, PBS Evolution Program Website (www.pbs.org/wgbh/evolution/index.html) This website is the gateway for information and teaching resources designed for the PBS video program Evolution.

4. Extinction!, 2001, PBS Evolution Program Website (www.pbs.org/wgbh/evolution/extinction/index.html) This website gives background information about past, and possible current, mass extinctions.

5. Hawaii Biodiversity and Mapping Program, Center for Conservation Resource and Training (hbmpweb.pbrc.hawaii.edu/ccrt/hbmp) The mission of this website is “to gather, synthesize, and disseminate comprehensive information on the status and location of Hawai’i's biological resources in order to assist others toward making a positive impact on biodiversity.” It contains cyber resources and a photo gallery specific to Hawaiian biodiversity.

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Audiovisual Materials 1. Evolution, 2001, PBS Home Video (www.shop.pbs.org) This program contains seven videos that discuss the history, science, and controversy surrounding the theory of evolution. Each video has its own website with information and teaching resources.

2. America’s Endangered Species: Don’t Say Goodbye, 1998, National Geographic Video (shop.nationalgeographic.com) In this video, two photographers travel across America learning about and photographing endangered species.

3. Scientific American Frontiers X: Voyage to the Galapagos, 1999, PBS video (www.shoppbs.org/home) Alan Alda follows Charles Darwin’s footsteps to the islands, learning about the animals and birds that inspired Darwin and the efforts to protect the unique biota from alien invaders—including the 60,000 ecotourists who visit every year.

4. David Attenborough’s documentaries Attenborough has produced many documentary films that discuss topics in ecology, biodiversity, and evolution. The films can be found on Amazon.com and Netflix.com. Relevant titles include: The Living Planet, 2004, WEA The Blue Planet, 2003, BBC Video The Life of Mammals, 2003, Warner Home Video The Life of Birds, 2002, BBC Video The Private Life of Plants, 1995, Turner Entertainment Video Life on Earth, 1987, Turner Home Video 5. Evolve, 2009, The History Channel This video series shows both classic and contemporary examples of evolution, by body system (for example: eyes, guts) or novel adaptations (for example: in communication, venom, sex). It is available on Amazon.com.

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Weighing the Issues Carrying Capacity and Human Population Growth Facts to consider: Human populations are subject to the same types of limiting factors as other organisms; however, we are adept at modifying our habitat to suit our needs. Because humans have become increasingly efficient at fulfilling needs, carrying capacities for humans have increased as the limiting factors have been modified. Increasingly sophisticated technologies will keep increasing the carrying capacity for humans as advances are made in agriculture and medicine, for example. However, technological progress relies on natural resources, which are becoming increasingly scarce. Natural resource exploitation, in some cases, degrades the environment to such a degree that an area is rendered unsafe for human habitation at the existing and possibly future technology levels. If this trend continues, the human carrying capacity may indeed be lowered.

How Best to Conserve Biodiversity?

Facts to consider: Perspective plays a very important role in biodiversity conservation. For example, humans establish boundaries for national parks and then expect nature to treat the park as a closed system. However, nature does not adhere to human-imposed boundaries, and the boundaries are porous, not impermeable. The problem comes when organisms that are supposed to stay inside park boundaries “invade” private land. This phenomenon has been seen when large predators, for instance, venture into suburban housing communities.

Conversely, organisms outside park borders can cross over to affect organisms within the park. In essence, biodiversity conservation is a “tragedy of the commons” dilemma, but society must understand that the size of the “commons” in terms of biodiversity conservation is much larger than popularly thought. A solution can lie in the redesign of some parks. In some instances, such as in Serengeti National Park, there is a buffer zone for conservation around the preserved national park. This area allows for protection of wildlife (from all except native herding populations) but isn’t as strict as the park itself, nor as lax as the residential/commercial land around it.

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The Science behind the Story Is Forest Restoration Boosting Bird Populations at Hakalau Forest?

Observation: Established in 1985, the Hakalau Refuge is home to nine species of native forest birds, including four federally endangered ones: the Hawaii ‘ākepa; the Hawaii creeper; the ‘akiapōlā‛au; and the ‘io, or Hawaiian hawk. A number of nonnative birds are now found here as well. Much of the region’s native forest had been cleared for cattle ranching years earlier while free-roaming pigs and invasive plants had degraded the rest.

Question: Has the restored forest brought higher populations of native forest birds?

Study: Beginning in 1987, federal biologists and trained observers conducted regular surveys of birds on the refuge. Following standard protocols, they performed “point counts” by walking transects, stopping for eight minutes at a time in predetermined spots and counting numbers of each species seen or heard.

With 343 points along 15 transects across the refuge, this sampling allowed them to estimate population densities for each bird species. Researchers then analyzed changes in these samples through time to make inferences about changes in population densities and population sizes.

Results: At a 2008 workshop and in a 2009 technical report, they concluded that populations of most native birds were either stable or slowly increasing across most of the refuge. With the data from Hakalau, linear regression led managers to conclude that over the 21-year period, in high-elevation pastures that managers were restoring to forest, populations of birds that used the young trees were rising sharply. In the middle-elevation open forest being managed, populations of all native birds were either stable or increasing.

How Do Species Form in Hawaii’s “Natural Laboratory” of Evolution?

Observation: The Hawaiian Islands comprise the most remote archipelago in the world, but over time a few plants and animals found their way there, establishing populations that evolved into new species. Once a species colonizes an island, it can often spread and evolve rapidly because competitors are few and there tend to be unoccupied niches.

Hypothesis: The radiation of Hawaiian honeycreepers stemmed from one colonizing ancestor.

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Results: Lerner’s team found that the Hawaiian honeycreepers apparently derive from one ancestor, and are most related to the Eurasian rosefinches, indicating that honeycreepers evolved after some rosefinch-like bird arrived from Asia. Perhaps a wandering flock of ancestral rosefinches was caught up in a storm long ago and blown to Hawaii. Once this common ancestor of today’s rosefinches and honeycreepers arrived on an ancient Hawaiian island, its progeny adapted to conditions there by natural selection, resulting in modified bill shape, diet, and coloration. They found that the rosefinch-like ancestor arrived by 5.7 mya, about the time that the oldest of today’s main islands (Kaua’i and Ni’ihau) were forming.

Local Connections The Hawaiian Islands are known for many unique species of plants and animals, and for special natural places (such as volcanoes, waterfalls, and coral reefs). But every place in the world has its own natural wonders. Do some research into your own region using library or online sources. Describe several distinctive plants or animals that occur in the region you live, and several special natural places in your region. From your own experience, what plant, animal, or place is most valuable to you, and why? Are any of these organisms or places at risk of being lost? Are any of them being affected by introduced species or other impacts? What is being done to safeguard the natural wonders of your region? Suggest steps that could be taken in your community to protect populations of species at risk.

Class time required: Ten minutes – one class period This exercise could be completed as a homework assignment or as a class activity.

Either way, it would be important to provide students with some guidance on appropriate sources. If you know of any websites with information about local organisms, provide students the links. In addition, the following links may be helpful.

1. IUCN Red List of Threatened Species www.iucnredlist.org/ 2. US Department of Agriculture, Natural Resources Conservation Service Plants database plants.sc.egov.usda.gov/java/ 3. US Department of the Interior Animals and Wildlife Links

www.doi.gov/library/internet/animals 4. US Fish and Wildlife Service Endangered Species

www.fws.gov/endangered/species/us-species.html

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Calculating Ecological Footprints Region

2017 Population

2018 Population

Population Growth Rate

Hawaii

1,424,203

1,420,491

–0.26%

Nevada

2,972,405

3,034,392

2.09%

Your state or city

Answers will vary

Answers will vary

Answers will vary

United States

325,147,121

327,167,434

0.62%

World

7,536,000,000

7,621,000,000

1.13%

1. 329,195,872.

2. 11.8 births per 1,000 people − 8.6 deaths per 1,000 people = 3.2/1,000 or 0.32% (rate of natural increase); 0.62% − 0.32% = 0.30%. The United States was experiencing more immigration than emigration during this period.

3. Nevada will experience greater demand for density-dependent resources, such as drinking water. As populations expand into natural areas, forests and other natural areas will be impacted. In addition, as people expand into natural areas, wildlife populations will be displaced or they will need to adapt to changes in their environment. Food supplies could be impacted, but most of the food in the United States is not grown locally, so it would likely be less affected.

4. Answers will vary. However, review the concept of the density-dependent factors from this chapter to craft your answer.

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4 Species Interactions and Community Ecology Chapter Objectives This chapter will help students: Summarize and compare the major types of species interactions Describe feeding relationships and energy flow, and use them to identify trophic levels and navigate food webs Discuss characteristics of a keystone species Characterize disturbance, succession, and notions of community change Describe the potential impacts of invasive species in communities and offer solutions to biological invasions Explain the goals and the methods of restoration ecology Identify and describe the terrestrial biomes of the world

Lecture Outline I.

Central Case Study: Black and White, and Spread All Over: Zebra Mussels Invade the Great Lakes A. Things were looking up for the Great Lakes. Their waters were becoming cleaner and cleaner as regulation by the US and Canadian governments brought industrial pollution under control starting in the 1970s.

B. Then the zebra mussel, a native to western Asia and eastern Europe, arrived by accident in the ballast water of ships.

C. Today, they have colonized waters in 30 U.S. states.

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D. The zebra mussels’ larval stage is well adapted for long-distance dispersal, and it has encountered none of the predators, competitors, and parasites that evolved to limit its population growth in the Old World.

E. Zebra mussels can clog up water intake pipes, damage boat engines, degrade docks, foul fishing gear, and sink buoys that ships use for navigation.

F. Zebra mussels also exert severe ecological impacts. They eat primarily phytoplankton: microscopic photosynthetic algae, protists, and cyanobacteria that drift in open water.

G. Phytoplankton is the foundation of the Great Lakes food web, so its depletion is bad news for zooplankton, the tiny aquatic animals that eat phytoplankton—and for the fish that eat both.

H. Although zebra mussels benefit many bottom-feeding animals, they can suffocate native mollusks by attaching to their shells.

I. Most recently, the zebra mussel is being displaced by the quagga mussel.

J. In areas where zebra mussels are declining, some of the native fish and invertebrates that suffered from their arrival are now recovering.

K. No one expects zebra mussels to disappear, but there is now hope that some of their impacts may be reversed and that the ecological communities of the Great Lakes can begin to be restored.

II.

Species Interactions A. Competition can occur when resources are limited.

1. When multiple organisms seek the same limited resource, their relationship is said to be one of competition. Competitive interactions can take place among members of the same species (intraspecific competition) or between members of different species (interspecific competition).

2. If one species is a very effective competitor, it may exclude other species from resource use entirely, an outcome called competitive exclusion.

3. If no single competitor fully excludes others, the species may continue to live side by side. This result is called species coexistence.

4. Coexisting species that use the same resources tend to adjust to their competitors to minimize competition with them.

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5. The full niche of a species is called its fundamental niche. An individual that plays only part of its role because of competition or another type of species interaction is said to display a realized niche.

6. Resource partitioning exists because the species partition, or divide, the resources they use in common by specializing in different ways.

7. Resource partitioning can lead to character displacement, in which competing species come to diverge in their physical characteristics because of the evolution of traits best suited to the range of resources they use.

B. Predators kill and consume prey.

1. Predation is the process by which an individual of one species— the predator—hunts, captures, kills, and consumes individuals of another species, the prey.

2. Predation can sometimes drive population dynamics.

3. Predation also has evolutionary ramifications.

C. Parasites exploit living hosts.

1. Parasitism is a relationship in which one organism, the parasite, depends on another, the host, for nourishment or some other benefit while doing the host harm.

2. Many types of parasites live inside their hosts. Other parasites are free living. Still other parasites live on the exterior of their host.

3. Parasites that cause disease in their hosts are called pathogens.

4. Just as predators and prey evolve in response to one another, so do parasites and hosts, in a reciprocal process of adaptation and counteradaptation called coevolution. Hosts and parasites may become locked in a duel of escalating adaptations, known as an evolutionary arms race.

D. Herbivores exploit plants.

1. In herbivory, animals feed on the tissues of plants.

2. Like animal prey, plants have evolved an impressive arsenal of defenses against the animals that feed on them.

3. Some plants recruit certain animals as allies to assist in their defense.

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E. Mutualists help one another.

1. Mutualism is a relationship in which two or more species benefit from interacting with one another.

2. Physically close association is called symbiosis, and symbiosis can be either mutualistic or parasitic.

3. Not all mutualists live in close proximity. Pollination, a mutualistic interaction vital to agriculture and our food supply, involves freeliving organisms that may encounter each other only once.

III.

Ecological Communities 1. A community is an assemblage of populations of organisms living in the same area at the same time.

A. Food chains consist of trophic levels.

1. As organisms feed on one another, matter and energy move through the community, from one rank in the feeding hierarchy, or trophic level, to another. a. Producers, or autotrophs (“self-feeders”), make up the first trophic level. b. Organisms that consume producers are known as primary consumers and comprise the second trophic level. c. The third trophic level consists of secondary consumers, which prey on primary consumers. d. Predators that feed at still higher trophic levels are known as tertiary consumers. e. Detritivores, such as millipedes and soil insects, scavenge the waste products or dead bodies of other community members. f. Decomposers, such as fungi and bacteria, break down leaf litter and other nonliving matter into simpler constituents that can be taken up and used by plants.

B. Energy decreases at higher trophic levels.

1. A general rule of thumb is that each trophic level contains about 10% of the energy of the trophic level below it.

2. This pyramid-like pattern also tends to hold for numbers of organisms; in general, fewer organisms exist at higher trophic levels than at lower ones. Because the difference in numbers of organisms among trophic levels tends to be large, the same pyramid-like relationship often holds true for biomass, the collective mass of living matter in a given place and time.

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3. The pyramid pattern illustrates why eating at lower trophic levels—being vegan or vegetarian, for instance—decreases a person’s ecological footprint.

C. Food webs show feeding relationships and energy flow.

1. As energy is transferred from lower trophic levels to higher ones, it is said to pass up a food chain, a linear series of feeding relationships.

2. A more accurate representation of the feeding relationships in a community is a food web—a visual map of energy flow that uses arrows to show the many paths along which energy passes as organisms consume one another.

D. Some organisms play outsized roles.

1. A species that has strong or wide-reaching impact far out of proportion to its abundance is often called a keystone species.

2. Predators at high trophic levels can indirectly promote populations of organisms at low trophic levels by keeping species at intermediate trophic levels in check—a phenomenon ecologists refer to as a trophic cascade.

3. Animals at high trophic levels—such as wolves, sea stars, sharks, and sea otters—are often viewed as keystone species that can trigger trophic cascades. However, other types of organisms also exert strong community-wide effects.

4. Less-conspicuous organisms at low trophic levels can exert still more impact.

E. Communities respond to disturbance in various ways.

1. In ecological terms, a disturbance is an event that has rapid and drastic impacts on environmental conditions, resulting in changes to the community and ecosystem.

2. A community that resists change and remains stable despite disturbance is said to show resistance to the disturbance.

Alternatively, a community may show resilience, meaning that it changes in response to disturbance but later returns to its original state.

F. Succession follows severe disturbance.

1. If a disturbance is severe enough to eliminate all or most of the species in a community, the affected site may then undergo a somewhat predictable series of changes that ecologists call succession.

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a. Primary succession follows a disturbance so severe that no vegetation or soil life remains from the community that had occupied the site. b. Secondary succession begins when a disturbance dramatically alters an existing community but does not destroy all life and organic matter in the soil.

2. Species that arrive first and colonize the new substrate are referred to as pioneer species. Pioneer species are well adapted for colonization, having traits such as spores or seeds that can travel long distances.

3. Processes of succession occur in many ecological systems.

4. In the traditional view of succession described here, the process leads to a climax community, which remains in place until some disturbance restarts succession.

G. Communities may undergo shifts.

1. Today, ecologists recognize that community change is far more variable and less predictable than early models of succession suggested. And, climax communities are not determined solely by climate, but vary with soil conditions and other factors from one time or place to another.

2. Once a community is disturbed and changes are set in motion, there is no guarantee that the community will ever return to its original state. Sometimes communities may undergo a regime shift, in which the character of the community fundamentally changes.

3. Many ecologists now think that human disturbance is creating wholly new communities that have not previously occurred on Earth. These no-analog communities are composed of novel mixtures of plants and animals and have no analog or precedent.

H. Invasive species may alter communities.

1. In our age of global mobility and trade, people have moved countless organisms from place to place, intentionally or by accident, such that today most nonnative arrivals in a community are introduced species—species introduced by people.

2. Most introduced species fail to establish populations, but some turn invasive, spreading widely and coming to dominate communities.

Such invasive species often thrive in disturbed systems and in turn disturb them further.

3. Introduced species may become invasive when limiting factors that regulate their population growth are absent.

4. Examples abound of invasive species that have had major ecological impacts.

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5. Ecologists tend to view the impacts of invasive species—and introduced species in general—in a negative light. Whatever view one takes, the impacts of introduced species on native populations and communities are significant, and they grow year by year with our increasing mobility and the globalization of our society.

I. We can respond to invasive species with control, eradication, or prevention.

1. In 1990, the US Congress passed legislation that led to the National Invasive Species Act of 1996.

2. Since this act was passed, funding has become available for the control and eradication of invasive species.

3. To prevent invasions, it helps to be able to predict where a given species might spread.

J. Communities can be restored.

1. Because ecological systems support our civilization and all life, when degraded systems cease to function, our health and wellbeing are threatened.

2. This realization has given rise to the science of restoration ecology, and the process of ecological restoration, or on-theground efforts to restore ecosystems to their natural “presettlement” conditions.

3. Many ecological restoration efforts are underway today.

4. As our population grows and development spreads, ecological restoration is becoming an increasingly vital conservation strategy.

However, restoration is difficult, time consuming, expensive, and it is not always successful. It is therefore best, whenever possible, to protect natural systems from degradation in the first place.

K. Climate change poses new challenges for restoration.

1. In today’s changing climate, restorationists are aiming to restore functions of communities and ecosystems and to create systems that are resilient and can adapt to climate change.

IV.

Earth’s Biomes

1. A biome is a major regional complex of similar communities—a large-scale ecological unit recognized primarily by its dominant plant type and vegetation structure.

A. Climate helps to determine biomes.

1. Which biome covers each portion of the planet depends on a variety of physical factors, including temperature, precipitation, soil conditions, and the circulation patterns of wind in the atmosphere and water in the oceans. Among these factors, temperature and precipitation exert the greatest influence.

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2. Mountain ranges can also alter climate through the rain shadow effect.

3. Because biomes are largely a function of climate, and because temperature and precipitation are the best indicators of an area’s climate, scientists use climate diagrams, or climatographs, to depict such information.

B. We can divide the world into ten terrestrial biomes.

1. Temperate deciduous forest dominates the landscape around the southern Great Lakes and is characterized by broad-leafed trees that are deciduous, meaning that they lose their leaves each fall and remain dormant during winter, when hard freezes would endanger leaves.

2. Traveling westward from the Great Lakes, temperature differences between winter and summer become more extreme, rainfall diminishes, and we find temperate grasslands.

3. The coastal Pacific Northwest region, with its heavy rainfall, features temperate rainforest. The soils of temperate rainforests are fertile but are susceptible to landslides and erosion if forests are cleared to extract lumber and commercially valuable products.

4. Tropical rainforest—found in Central America, South America, Southeast Asia, west Africa, and other tropical regions—is characterized by year-round rain and uniformly warm temperatures.

Tropical rainforests have dark, damp interiors, lush vegetation, and highly diverse communities, with more species of insects, birds, amphibians, and other animals than any other biome.

5. Tropical areas that are warm year-round but where rainfall is lower overall and highly seasonal give rise to tropical dry forest, or tropical deciduous forest, a biome widespread in India, Africa, South America, and northern Australia.

6. Drier tropical regions give rise to savanna, tropical grassland interspersed with clusters of acacias or other trees. The savanna biome is found across stretches of Africa, South America, Australia, India, and other dry tropical regions.

7. Where rainfall is very sparse, desert forms. The driest biome on Earth, most deserts receive well under 25 cm (9.8 in.) of precipitation per year, much of it during isolated storms months or years apart.

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8. Nearly as dry as desert, tundra occurs at very high latitudes in northern Russia, Canada, and Scandinavia. Extremely cold winters with little daylight and summers with lengthy days characterize this landscape of lichens and low, scrubby vegetation without trees.

9. The northern coniferous forest, or boreal forest, often called taiga, extends across much of Canada, Alaska, Russia, and Scandinavia.

These forests develop in cooler, drier regions than do temperate forests, and they experience long, cold winters and short, cool summers.

10. In contrast to the boreal forest’s broad, continuous distribution, chaparral is limited to small patches widely flung around the globe. Chaparral consists mostly of evergreen shrubs and is densely thicketed.

C. Aquatic and coastal systems resemble biomes.

1. Areas equivalent to biomes also exist in the oceans, along coasts, and in freshwater systems.

2. Unlike terrestrial biomes, aquatic systems are shaped not by air temperature and precipitation, but by water temperature, salinity, dissolved nutrients, wave action, currents, depth, light levels, and type of substrate (e.g., sandy, muddy, or rocky bottom).

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Key Terms biomass

pollination

biome

predation

boreal forest

primary consumers

chaparral

primary succession

character displacement

producers

climate diagrams

rain shadow

climax community

realized niche

coevolution

regime shift

community

resilience

competition

resistance

competitive exclusion

resource partitioning

decomposers

restoration ecology

desert

savanna

detritivores

secondary consumers

disturbance

secondary succession

ecological restoration

species coexistence

food chain

succession

food web

symbiosis

fundamental niche

temperate deciduous forest

herbivory

temperate grasslands

introduced species

temperate rainforest

invasive species

tertiary consumers

keystone species

trophic cascade

mutualism

trophic level

no-analog communities

tropical dry forest

parasitism

tropical rainforest

pathogens

tundra

phytoplankton

zooplankton

pioneer species

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Teaching Tips 1. Have students research a local environment and create a graphic of a food web in that environment.

2. Have students investigate local invasive species and the impacts that they have had, not just environmentally but also economically.

3. Ask your students to think of examples of species interactions that are not discussed in the textbook. You may need to guide them through a classic example, such as the mutualism between oxpeckers and the black rhinoceros.

4. Rather than teaching about biomes yourself, have your students do a biome project to learn from each other. Separate the students into small groups and have them choose a biome or a special subset of a biome to study, such as wetlands divided into swamps, marshes, bogs, and estuaries; deserts divided into hot deserts and cool deserts; or ocean shorelines divided into sandy shores, rocky (tidepool) shores, and barrier islands. The groups can then create a poster or a short PowerPoint presentation on their chosen topic. This would need to include: • World distribution of the biome (include a map) • Major characteristics of the biome—elevation, geology, climate, temperature, rainfall, seasonality, and winds • Several representative animals and plants • Indigenous peoples • Two anthropogenic problems that threaten the biome • Something that is being done to address one of the problems as well as its results • A table, graph, or chart relating to the biome • A listing of resources that were used in researching the project Grading should be based on the satisfactory gathering of the above information as well as on an oral presentation, if time permits. The oral presentation should include: • An introduction with a question, humor, or attention-getting fact • Good transitions between presenters and topics within the presentation • Presentation of the material without notes and using proper pronunciation • Loud, clear voices and good presentation appearance • Good closure, with a summary, a final idea, humor, a suggestion for action, or other appropriate ending

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Additional Resources Websites 1. The World’s Biomes, University of California Museum of Paleontology (www.ucmp.berkeley.edu/glossary/gloss5/biome) This resource describes the major biomes: aquatic, deserts, grasslands, forests, and tundra.

2. Invasivespeciesinfo.gov, National Agricultural Library, US Department of Agriculture (www.invasivespeciesinfo.gov) This website is a gateway to federal and state invasive species programs, activities, databases, and links to primary documents and related websites.

3. Killer Whales Thinning Otter Population, All Things Considered, 2005.

National Public Radio (www.npr.org/templates/story/story.php?storyId=4665067) This web-based audio news report addresses the theory that orca are causing severe decreases in the Alaskan sea otter population. Sea otters are a keystone species.

4. Society for Ecological Restoration International Online, Society for Ecological Restoration International (www.ser.org) This is the home page for the Society for Ecological Restoration International, with links to past and existing restoration projects and primary documentation.

5. The Natural Resources Defense Council features a web-based system called Biogems (www.nrdc.org/biogems) In this search mode, students can learn about the unique natural “gems” highlighted based on their biodiversity, scenic beauty, significance as habitats for endangered species, or whether they are in danger of being developed.

Audiovisual Materials 1. Biomes, 2002, a Cambridge Educational production distributed by Films for the Humanities and Sciences (www.films.com) This is a five-part program that examines biomes as interconnected parts of a global ecosystem. It is available in digital-on-demand format.

2. Plants Out of Place: Facing the Green Invasion, 2001, distributed by Films for the Humanities and Sciences (www.films.com) This program illustrates the alarming environmental and commercial impact of nonnative invasive plants. It is available on DVD and in digital-on-demand formats.

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3. Varmints, 1999, produced by High Plains Films and distributed by Bullfrog Films (www.bullfrogfilms.com) This program chronicles the decline of the prairie dog—a keystone species—in the American West.

4. Interdependence of Life, 2005, a Cambridge Educational Production, distributed by Films for the Humanities and Sciences (www.films.com) This program examines the world’s ecosystems and explains their flow of energy and cycling of matter.

5. Living Together: Relationships in the Wild, 2004, a BBC production, distributed by Films for the Humanities and Sciences (www.films.com) This program looks at how relationships between living things have promoted the diversity and splendor of life as it exists on Earth today.

6. Cane Toads: An Unnatural History, 1988. Directed by Mark Lewis (www.amazon.com/movies-tv/dp/6302212812) This comical documentary chronicles the biocontrol failure of bringing cane toads to Australia to control the cane beetle. Cane toads became an invasive species as a result.

7. Planet Earth I and II, 2006 and 2007. BBC production This 17- episode series explores Earth’s most iconic habitats. In each episode, iconic species are highlighted and environmental challenges are explored.

Weighing the Issues The Footprints of Our Diets Facts to consider: The student should consider that energy is lost as it moves up a food web or food chain (from producers to tertiary consumers). Eating producers and primary consumers involves less energy loss through the food web or chain than does eating secondary and tertiary consumers (as fewer energy conversions are involved). Also, reducing animal products inevitably reduces one’s ecological footprint, as you aren’t eating the energy from the plants through an intermediary (cow, pig, chicken, etc.). Encourage students to track the amount of meat, milk, eggs, or other animal products for a day, several days, or a week to get an accurate estimate of their consumption. Then ask them honestly if they would be willing to eliminate even one animal product meal a year in favor of a better ecological footprint.

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Are All Nonnative Species Bad? Facts to consider: A community is a group of populations that interacts in specific ways due to coevolution. When an invasive species moves in, these relationships are disrupted. Because nonnative species are usually better competitors for resources due to a lack of factors limiting their population growth, they can cause population reductions and even the extinction of native species that use the same niche as the invader. The alien species can also have a huge impact on the entire food web of a community if it is a producer or primary consumer because it decreases the food resources for native organisms higher in the food web. This situation is a major problem for any community, at least in the short term. In the long term (over hundreds or thousands of years), small changes in the local environment would allow for a slower advance of an invasive species, permitting native species to evolve and coexist with the invader and turning the nonnative species into a native one. This is how succession occurs. Human intervention brings in a very large number of invasive species at a very fast rate, which can stop the process of evolution. A personal response is required to address ethical standards for accepting or rejecting a nonnative species in any community.

Restoring “Natural” Communities Facts to consider: The definition of natural will vary among students. The text refers to “historical conditions of ecological communities . . . before our industrialized civilization altered them.” However, the question of when “presettlement conditions” occurred is a matter of debate. In considering the specific scenario addressed in the question, students should consider historical data that may indicate changes in climatic conditions, and whether it is feasible to reintroduce species that used to live in the restoration area. Have the climate and environmental conditions changed too much to allow the reintroduced species to thrive? Do the species that were a major part of the historical community still exist? The farther back in time ecologists consider presettlement conditions for a community, the more these two questions will affect the restoration effort.

The Science behind the Story How Do Asian Carp Affect Aquatic Communities?

Observation: As four species of Asian carp began to spread through the Mississippi River system, people became worried that native communities would be impacted. Fishermen in the area noticed changes in their catch, but ecological communities are complex and more research was needed.

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Hypothesis: Introduction of Asian carp would exert population-level effects over large areas on two native plankton-eating fish: gizzard shad and bigmouth buffalo.

Study: Phelps and his team used three independent approaches to examine the competition between Asian carp and native fish. First, the team used existing long-term data (collected from 1993–2012) on fish populations in the Mississippi River Basin, from Minnesota to Missouri. They compared northern locations, where carp had not invaded, to southern sites, where carp had invaded. Second, the team sampled four floodplain lakes in Illinois and Missouri immediately after a major flood event and five months later. During the flood event in 2011, three of the lakes were invaded by silver carp and one was not. The team compared changes in native fish populations in the invaded and non-invaded lakes over the five-month period. Third, the team used controlled laboratory experiments to investigate interspecific competition and survival. In the lab, silver carp and two native fishes—gizzard shad and bigmouth buffalo—were placed in tanks to determine whether interspecific competition affected their survival. Silver carp were placed in tanks with gizzard shad and separately with bigmouth buffalo.

Then, the native fish were placed in tanks with individuals of their own species to obtain comparative data on intraspecific competition.

Results: All the data analyzed supported the researchers’ hypotheses. In the first part of the study, researchers found that in portions of the Mississippi River Basin that had been invaded by Asian carp, the populations of the native gizzard shad and bigmouth buffalo had declined over time. In the second part of the study, the team found that native fish populations decreased over the five-month study period in the lakes invaded by silver carp while the lake that was not invaded showed no change. In addition, the team found that the lake that was highly invaded by silver carp showed the greatest change in native species populations. In the third part of the study, the team found that when silver carp and gizzard shad were placed together, only 10% of the shad survived for the 14-day experiment. When bigmouth buffalo were placed with silver carp, their biomass decreased dramatically, but most individuals survived. Together, these three investigations clearly show that Asian carp have a negative impact on the growth and survival of native fish species in the Mississippi River Basin.

How Do Communities Recover after Catastrophic Disturbance?

Observation: During the eruption of Mount St. Helens, 4.1 km3 (1.0 mi3) of material was ejected from the mountain, severely altering 1650 km2 (637 mi2), an area larger than the entire city of Houston, Texas.

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Hypothesis: Based on traditional views of succession, scientists expected that pioneer species would colonize the area gradually, spreading slowly from the outside margins inward, and that over many years a community would be rebuilt in a systematic and predictable way.

Study: Dale’s team used sticky traps to sample seeds as they chronicled the area’s recovery. Roger del Moral of the University of Washington and his colleagues compared ecological responses on a variety of surfaces, including barren pumice, mixed ash and rock, mudflows, and the “blowdown zone” where trees were toppled like matchsticks. As elk from surrounding forests moved into the region, Dale and her team fenced off “exclosure” plots to compare how plants grew within the ungrazed exclosures versus in plots grazed by elk outside the exclosures.

Results: Plant regrowth was very slow at Dale’s study plots for several years and then accelerated. After 20 years, 150 species of plants covered 65% of the ground.

Windblown seeds accounted for most regrowth, but plants that happened to survive in sheltered “refugia” within the impact zone helped to repopulate areas nearby. Also, chance played a large role in determining which organisms survived and how vegetation recovered, del Moral and others found. Animals played major roles in the recovery right from the beginning. Researchers estimated that more than 1500 species arrived in the first few years, surviving by scavenging or by preying on other arthropods. Most individuals soon died, but the nutrients from their bodies enriched the soil, helping the community to develop. Once plants took hold, animals began exerting influence through herbivory. Both types of plots saw increases in plant cover and similar amounts of species diversity because elk herbivory can spur plant growth that compensates for what they eat. Nonnative species did best in the grazed plots, whereas species important for forest recovery did best in the ungrazed exclosures. Overall, elk herbivory did not stall plant regrowth.

Conclusions: Research at Mount St. Helens has shown that succession is not a simple and predictable process. The results from Mount St. Helens also show life’s resilience. Ecological change at Mount St. Helens is still in its early stages and will continue for many decades more.

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Local Connections Asian carp have invaded waterways across much of the eastern and central United States, and the Great Lakes are home to more than 180 introduced species. But every location in the world by now has its own suite of introduced, nonnative, species. Research and describe one plant species and one animal species (aside from Asian carp) that have been introduced in the region where you live. What impacts (bad, good, or neutral) have each of these species had on ecological communities in your region? What economic impacts have they had? What specific efforts are being made in your region to deal with invasive species considered harmful? What are some results of these efforts so far?

Class time required: Ten minutes – one class period This exercise could be completed as a homework assignment or as a class activity.

Either way, it would be important to provide students with some guidance on appropriate sources. If you know of any websites with information about local invasive species, provide students with the links. Keep in mind that invasive species are often location-specific. All invasive species are native species somewhere. The following links may be helpful.

1. Center of Invasive Species and Ecosystem Health www.invasive.org/ 2. Global Invasive Species Database www.iucngisd.org/gisd/100_worst.php 3. US Department of Agriculture, Invasive Species Lists www.invasivespeciesinfo.gov/subject/lists

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Calculating Ecological Footprints Group of organisms

Percentage of total introduced

Number of species introduced

Percentage of total annual costs

Annual economic costs

Plants

50.0

25,000

27.2

$34.65 billion

Microbes

40.0

20,000

20.2

$25.73 billion

Arthropods

9.0

4,500

15.7

$20 billion

Fish

0.28

140

4.2

$5.35 billion

Birds

0.19

95

1.5

$1.9 billion

Mollusks

0.18

90

1.7

$2.17 billion

Reptiles and Amphibians

0.11

55

0.009

$0.011 billion

Mammals

0.04

20

29.4

$37.5 billion

TOTAL

100

50,000

100

$127.4 billion

Source: Pimentel, D., R. Zuniga, and D. Morrison. 2005. Update on the environmental and economic costs associated with alien-invasive species in the United States.

Ecological Economics 52: 273–288.

1. Two ways in which exotic plants might be brought to a new environment could be by accident: in bringing in exotic species to decorate a native landscape, or when seeds appearing as food products are brought to a new location via air travel. We can prevent these nonnative plants from establishing in new areas by actively screening them from entering the native environment, for example, via airport customs, or by working to remove exotic species before they become invasive.

2. We can be conscious of the products we buy abroad, knowing that these products could contain different microbes or arthropod stowaways. We can actively look for these organisms at country borders. Additionally, we could not move firewood from one location to burn it in another.

3. Answers will vary.

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5 Environmental Systems and Ecosystem Ecology Chapter Objectives This chapter will help students: Describe environmental systems Define ecosystems and discuss how living and nonliving entities interact in ecosystem-level ecology Outline the fundamentals of landscape ecology and ecological modeling Explain ecosystem services and describe how they benefit our lives Compare and contrast how water, carbon, nitrogen, and phosphorus cycle through the environment and explain how human activities affect these cycles

Lecture Outline I.

Central Case Study: Saving the Chesapeake Bay Ecosystem A. The demise of Deal Island, Maryland, was caused by the collapse of the Chesapeake Bay oyster fishery.

B. Chesapeake Bay was once a thriving system. Nutrients carried to the bay by streams in its roughly 168,000 km2 (64,000 mi2) watershed— the land area that funnels water to the bay through rivers—nourished the underwater environment. Hundreds of millions of oysters kept the bay’s water clear by filtering nutrients and phytoplankton (microscopic photosynthetic algae, protists, and cyanobacteria that drift near the surface) from the water column.

C. The intensive harvest of bay oysters for export began in the 1830s, and by the 1880s the bay boasted the world’s largest oyster fishery.

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D. But by 2010, the bay’s oyster populations had been reduced to a mere 1% of their historical abundance.

E. In addition to overharvesting, one of the biggest impacts on oysters in recent decades is the pollution of the bay with high levels of the nutrients nitrogen and phosphorus from agricultural fertilizers, animal manure, stormwater runoff, and atmospheric compounds produced by fossil fuel combustion. Oysters naturally filter nutrients from water, but with so few oysters in the bay, elevated nutrient levels have caused phytoplankton populations to increase. When phytoplankton die, settle to the bay bottom, and are decomposed by bacteria, oxygen in the water is depleted (a condition called hypoxia), which creates “dead zones” in the bay.

F. Recent events in the Chesapeake have offered hope for the recovery of the Chesapeake Bay system.

II.

Earth’s Environmental Systems A system is a network of relationships among parts, elements, or components that interacts with and influences one another through the exchange of energy, matter, or information.

A. System boundaries are often difficult to delineate.

1. Scientists sometimes divide Earth’s components into “structural spheres.” a. The lithosphere is the rock and sediment beneath our feet, the planet’s uppermost mantle and crust. b. The atmosphere is composed of the air surrounding our planet. c. The hydrosphere encompasses all water—salt or fresh, liquid, ice, or vapor—in surface bodies, underground, and in the atmosphere. d. The biosphere consists of all the planet’s organisms and the abiotic (nonliving) portions of the environment with which they interact.

2. The study of interactions among living and nonliving things is a key part of ecology at the ecosystem level.

3. Systems seldom have well-defined boundaries, so deciding where one system ends and another begins can be difficult.

4. No matter how we attempt to isolate or define a system, we soon see that it has connections to systems larger and smaller than itself.

Systems may exchange energy, matter, and information with other systems, and they may contain or be contained within other systems.

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B. Systems exhibit several defining properties.

1. It is difficult to understand systems fully just by focusing on their individual components because systems can have emergent properties, characteristics not evident in the components alone.

C. Systems involve feedback loops.

1. Sometimes a system’s output can serve as input to that same system, a circular process described as a feedback loop. In a negative feedback loop, output that results from a system moving in one direction acts as input that moves the system in the other direction.

2. Rather than stabilizing a system, positive feedback loops drive the system further toward an extreme. In positive feedback, increased output from a system leads to increased input, leading to further increased output.

3. In a system stabilized by negative feedback, when processes move in opposing directions at equivalent rates so that their effects balance out, they are said to be in dynamic equilibrium. Processes in dynamic equilibrium can contribute to homeostasis, the tendency of a system to maintain constant or stable internal conditions.

D. Environmental systems interact.

1. For a scientist interested in runoff (precipitation that flows over land and enters waterways) and the flow of water, sediment, or pollutants, it may make the most sense to define the bay’s watershed as a system. In environmental science, identifying the boundaries of systems depends on the questions being asked.

2. The dead zones in the Chesapeake Bay are due to the extremely high levels of nitrogen and phosphorus delivered to its waters from the six states in its watershed and the 15 states in its airshed—the geographic area that produces air pollutants likely to end up in a waterway.

3. Elevated nitrogen and phosphorus inputs cause phytoplankton in the bay’s waters to flourish. However, in the process of nutrient overenrichment, blooms of algae, increased production of organic matter, and subsequent ecosystem degradation are known as eutrophication.

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III.

Ecosystems 1. An ecosystem consists of all organisms and nonliving entities that occur and interact in a particular area at the same time.

2. British ecologist Arthur Tansley recognized that biological entities

are tightly intertwined with chemical and physical entities. For instance, in the Chesapeake Bay estuary—a water body where rivers flow into the ocean, mixing fresh water with saltwater— aquatic organisms are affected by the flow of water, sediment, and nutrients from the rivers that feed the bay and from the land that feeds those rivers.

3. Ecosystems are systems that receive inputs of energy, process and

transform that energy while cycling matter internally, and produce outputs (such as heat, water flow, and animal waste products) that enter other ecosystems.

A. Energy flows and matter cycles through ecosystems.

1. Energy flows in one direction through ecosystems. Most energy arrives as radiation from the sun, powers the system, and exits in the form of heat. Matter, in contrast, is generally recycled within ecosystems.

2. As autotrophs, such as green plants and phytoplankton, convert solar energy to the energy of chemical bonds in sugars through photosynthesis, they perform primary production. Specifically, the total amount of chemical energy produced by autotrophs is termed gross primary production. Ecologists call the energy that remains after respiration and that is used to generate biomass net primary production.

3. Heterotrophs use the energy they gain from plant biomass for their own metabolism, growth, and reproduction. Some of this energy is used by heterotrophs to generate biomass in their bodies, which is termed secondary production.

B. Ecosystems vary in their productivity.

1. Ecosystems vary in the rate at which autotrophs convert energy to biomass. The rate at which this conversion occurs is termed productivity, and ecosystems whose plants convert solar energy to biomass rapidly are said to have high net primary productivity.

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C. Nutrient availability influences productivity.

1. Nutrients are elements and compounds that organisms require for survival. a. Elements and compounds required in relatively large amounts are called macronutrients. b. Nutrients needed in small amounts are called micronutrients.

2. Nutrients stimulate production by plants, and lack of nutrients can limit production.

3. Increased nutrient pollution from farms, cities, and industries has led to the development of more than 475 documented hypoxic dead zones globally today, including that of the Chesapeake Bay as well as a large dead zone that forms each year in the Gulf of Mexico off the Louisiana coast near the mouth of the Mississippi River.

4. The good news is that in locations where people have reduced nutrient runoff, dead zones have begun to disappear.

D. Ecosystems interact across landscapes.

1. For some purposes, scientists even view the entire biosphere as a single, all-encompassing ecosystem.

2. Adjacent ecosystems may share components and interact extensively. Areas where ecosystems meet may consist of transitional zones called ecotones, in which elements of each ecosystem mix.

3. In a broad-scale approach, called landscape ecology, scientists study how landscape structure affects the abundance, distribution, and interaction of organisms.

4. A landscape is made up of a spatial array of patches spread spatially over a landscape in a mosaic.

5. The scale at which an ecologist focuses will depend on the questions he or she is interested in and on the organisms he or she is studying.

6. A network of subpopulations, most of whose members stay within their respective patches but some of whom move among patches or mate with members of other patches, is called a metapopulation.

7. Because of extinction risk, metapopulations and landscape ecology are of great interest to conservation biologists.

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E. Technology helps us practice landscape ecology.

1. A common tool for research in landscape ecology is the geographic information system (GIS). A GIS consists of computer software that takes multiple types of data (for instance, on geology, hydrology, topography, vegetation, animal populations, and human infrastructure from both on-ground studies and satellite imagery) and combines them, layer by layer, on a common set of geographic coordinates.

2. GIS has become a valuable tool used by geographers, landscape ecologists, resource managers, and conservation biologists.

F. Modeling helps ecologists understand systems.

1. A model is a simplified representation of a complex natural process. Ecological modeling is the practice of constructing and testing models that aim to explain and predict how ecological systems function.

2. Because ecological processes involve so many factors, ecological models can be mathematically complicated.

3. Models are essentially hypotheses about how systems function.

G. Ecosystem services sustain our world.

1. When Earth’s ecosystems function normally and undisturbed, they provide goods and services that we could not survive without called natural resources and ecosystem services.

2. Ecological processes form the soil that nourishes our crops, purify the water we drink, pollinate the food plants we eat, and break down (some of) the waste and pollution we generate.

3. One of the most important ecosystem services is the cycling of nutrients.

IV.

Biogeochemical Cycles A. Nutrients circulate through ecosystems in biogeochemical cycles.

1. Nutrients move through ecosystems in nutrient cycles, also known as biogeochemical cycles.

2. Nutrients and other materials move from one reservoir, or pool, to another, remaining for varying amounts of time (the residence time) in each. a. The rate at which materials move between reservoirs is termed a flux. b. When a reservoir releases more materials than it accepts, it is called a source.

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c. When a reservoir accepts more materials than it releases, it is called a sink.

3. Human activity can affect residence times, fluxes, and the ratio of nutrients in reservoirs.

B. The water cycle affects all other cycles.

1. Water is the essential medium for all manner of biochemical reactions. The hydrologic cycle, or water cycle, summarizes how water—in liquid, gaseous, and solid forms—flows through our environment.

2. The oceans are the main reservoir in the water cycle, holding 97% of all water on Earth. Less than 1% of planetary water is usable by humans.

3. Water moves from oceans, lakes, ponds, rivers, and moist soil into the atmosphere by evaporation, the conversion of a liquid to a gaseous form. Water also enters the atmosphere via transpiration, the release of water vapor by plants, through their leaves, or by evaporation from the surfaces of organisms.

4. Water returns from the atmosphere to Earth’s surface as precipitation when water vapor condenses and falls as rain or snow. This moisture may be taken up by plants and used by animals, but much of it flows as runoff into streams, rivers, lakes, ponds, and oceans.

5. Some precipitation and surface water soaks down through soil and rock and becomes groundwater, water found within the soil.

Groundwater recharges aquifers, sponge-like regions of rock and soil that are underground reservoirs of water. The upper limit of groundwater held in an aquifer is referred to as the water table.

C. Our impacts on the water cycle are extensive.

D. The carbon cycle circulates a vital organic nutrient.

1. Carbon is an ingredient in carbohydrates, fats, and proteins and occurs in the bones, cartilage, and shells of all living things. The carbon cycle describes the routes carbon atoms take through the environment.

2. This occurs in photosynthesis, cellular respiration, and in energy transfer between trophic levels in food webs.

3. Sediment storage of carbon occurs in fossil fuel deposits and sedimentary rock.

4. The world’s oceans are the second largest reservoir in the carbon cycle.

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E. We are shifting carbon from the lithosphere to the atmosphere.

1. By mining fossil fuel deposits, we are essentially removing carbon from an underground reservoir with a residence time of millions of years. By combusting fossil fuels, we release carbon dioxide and greatly increase the flux of carbon from the ground to the air.

2. In addition, cutting down forests removes carbon from the pool of vegetation and releases it to the air. And, if less vegetation is left on the surface, there are fewer plants to draw CO2 back out of the atmosphere.

3. The ongoing flux of carbon into the atmosphere is the driving force behind today’s anthropogenic global climate change.

4. Some of the excess CO2 in the atmosphere is now being absorbed by ocean water. This is causing ocean water to become more acidic, leading to problems that threaten many marine organisms.

5. Our understanding of the carbon cycle is not yet complete.

F. The nitrogen cycle involves specialized bacteria.

1. Nitrogen makes up 78% of our atmosphere by mass and is the sixth most abundant element on Earth. The nitrogen cycle involves chemically inert nitrogen gas, which most living organisms cannot use. This makes the atmosphere the major reservoir for nitrogen.

2. To become biologically available, inert nitrogen gas (N2) must be “fixed,” or combined with hydrogen in nature to form ammonia (NH3), whose water-soluble ions of ammonium (NH4+) can be taken up by plants. Nitrogen fixation can be accomplished in two ways: a. by the intense energy of lightning strikes. b. when air in the top layer of soil comes in contact with particular types of nitrogen-fixing bacteria. These bacteria live in a mutualistic relationship with many types of plants, including soybeans and other legumes, providing them nutrients by converting nitrogen to a usable form.

3. Other types of specialized bacteria then perform a process known as nitrification. In this process, ammonium ions are first converted into nitrite ions (NO2−), then into nitrate ions (NO3−). Plants can take up these ions, which also become available after atmospheric deposition on soils or in water or after application of nitrate-based fertilizer.

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4. The next step in the nitrogen cycle occurs when denitrifying bacteria convert nitrates in soil or water to gaseous nitrogen via a multistep process. Denitrification thereby completes the cycle by releasing nitrogen back into the atmosphere as a gas.

G. We have greatly influenced the nitrogen cycle.

1. Historically, nitrogen fixation was a bottleneck—a step that limited the flux of nitrogen out of the atmosphere. The Haber-Bosch process allows people to overcome the limits on productivity long imposed by nitrogen scarcity in nature.

H. The phosphorus cycle circulates a limited nutrient.

1. The element phosphorus (P) is a key component of cell membranes and of several molecules vital for life, including DNA, RNA, ATP, and ADP. The phosphorus cycle has no appreciable atmospheric component.

2. The vast majority of Earth’s phosphorus is contained within rocks and is released only by weathering.

3. Aquatic producers take up phosphates from surrounding waters, whereas terrestrial producers take up phosphorus from soil water through their roots. This element is then passed through consumers to decomposers back to the soil in a food web.

I. We affect the phosphorus cycle.

1. People increase phosphorus concentrations in surface waters through runoff of the phosphorus-rich fertilizers we apply to lawns and farmlands. We also add phosphorus to waterways through releases of treated wastewater rich in phosphates from the detergents we use to wash our clothes and dishes.

J. Tackling nutrient enrichment requires diverse approaches.

1. These approaches have widely varying costs for the same level of nutrient reduction.

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Key Terms airshed aquifers atmosphere biogeochemical cycles biosphere bottleneck carbon cycle conservation biologists denitrifying bacteria dynamic equilibrium ecological modeling ecosystem ecotones emergent properties estuary eutrophication evaporation feedback loop flux geographic information systems gross primary production groundwater Haber-Bosch process homeostasis hydrologic cycle hydrosphere hypoxia landscape ecology lithosphere macronutrients

metapopulation micronutrients model mosaic negative feedback loop net primary production net primary productivity nitrification nitrogen cycle nitrogen fixation nitrogen-fixing bacteria nutrient cycles nutrients patches phosphorus phosphorus cycle positive feedback loop precipitation primary production productivity reservoir residence time runoff secondary production sink source system transpiration watershed water table

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Teaching Tips 1. Ask students to conduct Internet research on the Gulf of Mexico’s dead zone.

Ask them to find out its current status, whether it has increased or decreased in size, and what is being done to address the problem. Then ask students to conduct Internet research on the Chesapeake Bay dead zone. Compare and contrast the two dead zones.

2. Consider dividing students into small groups, each of which will make an oral presentation during the semester. This chapter’s group might seek out the current research on carbon sequestration by the oceans, carbon credits, terrestrial capture by forests, or direct burial of CO2 from power generation.

3. Describe human activities that are affecting the flux rates in each of the major biogeochemical cycles. Divide students into small groups and have each group take one of the cycles, either on land, in freshwater, or in the oceans, and research the human effects. Depending on the size of the class, you may need to divide them further; you might do so by industrialized countries, emerging economies, and nonindustrialized countries, or by continent. Groups could present their findings as written reports, posters, Web pages, or oral presentations.

4. Have students make a table that compares and contrasts the major biogeochemical cycles, their reservoirs (indicating which is the sink and which is the source), time frames for flux, and other pertinent information. This could be done in groups or individually, and during a lab period or for homework.

5. Consider having students make a miniature biosphere as a lab project. They have to think about producers, consumers, detritivores, nutrient cycling, water cycles, energy input, and waste heat. Small aquariums covered with glass or plastic sheeting can be used if you have space for such a long-term project.

Otherwise, see the ideas listed at www.bottlebiology.org, a website maintained by the University of Wisconsin-Madison through an NSF grant. Some ideas there are very simplistic, but students can create a fairly sophisticated biosphere using the techniques. These biospheres have the advantages of being inexpensive and taking up little space in a class or lab.

6. Community service: Ask students to brainstorm, individually or as a group, ways in which they might explore the issues of this chapter in their community and take action. A specific example might be to educate consumers about the use of phosphates in dishwashing detergents. If your course contains a service learning component, some students might want to take an idea from this section as a project.

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Additional Resources Websites 1. Chesapeake Bay TMDL, US Environmental Protection Agency (www.epa.gov/reg3wapd/tmdl/ChesapeakeBay/index.html) This website provides background information about the current status of the Chesapeake Bay and its watershed.

2. National Centers for Coastal Ocean Science Gulf of Mexico Hypoxia Assessment, NOAA’s National Ocean Service (research/stressor-impacts-mitigation/habhrca/ngomex/) This website provides an integrated assessment of hypoxia in the Gulf of Mexico.

3. Water Resources of the United States, USGS (www2.usgs.gov/water) This website is the gateway to data, reports, and educators’ resources on water science.

4. PMEL Ocean Acidification Home Page, NOAA (pmel.noaa.gov/co2/ story/Ocean+Acidification) This is an extensive set of resources on ocean acidification and the problems that it creates for marine organisms.

5. CSiTE: Carbon Sequestration in Terrestrial Ecosystems Homepage, DOE (www.energy.gov/fe/articles/doe-manual-studies-terrestrial-carbonsequestration) A good starting point for research on carbon sequestration.

Audiovisual Materials 1. Strange Days on Planet Earth, 2005, National Geographic (www.pbs.org/strangedays) This two-DVD set follows scientists as they try to solve a series of mysteries.

2. Bill Moyers Reports: Earth on Edge, 1999 (www.pbs.org/earthonedge/ecosystems) This video focuses on five major types of ecosystems—freshwater, agriculture, forests, grasslands, and coastal.

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3. Poisoned Waters, Public Broadcasting System, 2009 (www.pbs.org/wgbh/pages/frontline/poisonedwaters) This website and associated documentary contain information regarding public policy pertaining to freshwater, the Chesapeake Bay watershed, and the effects of water pollution.

Weighing the Issues Ecosystems Where You Live Facts to consider: When describing ecosystems, one needs to include the interdependent biotic and abiotic components (temperature, precipitation, latitude, and elevation as well as water table, soil type, and nutrient flow). Because all ecosystems are part of a set of contiguous ecosystems, what flows into one ecosystem has flowed out of at least one other ecosystem. If one ecosystem is disturbed, ecosystems that are “downstream” will suffer a loss of materials (such as water) or be susceptible to damage from any artificial additions at the disturbed site (such as petroleum or fertilizers). Flora and fauna of the disturbed area will be greatly affected, possibly affecting those in nearby systems. Invasive species, which are better competitors in stressful environments, may establish themselves in the disturbed ecosystems, forcing native species to disappear through local extinction or through migration to more favorable habitats.

Water Shortages and You Facts to consider: It is important to consider all aspects of the hydrologic cycle when looking at water quality and quantity issues as well as how hydrologic cycles will differ from region to region. A good answer will refer to precipitation, infiltration, and recharge while discussing the relationship between surface water and groundwater. Regional information about water quantity and quality issues can be found at the US Geological Survey’s website (water.usgs.gov).

Here are some guiding questions to help students find out about their regional water issues: What is the water source? How many users are there? Is the population growing? Has the depth of the water table changed? Is the economic base changing (i.e., becoming more particular about the water quality while at the same time producing more hazardous waste from facilities such as computer chip factories)? What happens to sewage, storm runoff, and hazardous waste?

Nitrogen Pollution and Its Financial Impacts Facts to consider: This is a political question with no clear right or wrong answer.

When the interests of different regions are at odds, it’s to their advantage to work out their differences themselves because they know the problem best and may be 82 ..

able to reach an agreement that satisfies all sides. However, if the federal government intervenes, it should take into account the problems and needs of all affected parties to attempt a fair compromise. This is a cost-benefit analysis, where agriculture’s benefit to the nation is to be weighed against the value of the bay fisheries and the massive environmental impact on the land and water. The health of the bay’s waters should be taken into consideration as well as the impact on human health in future decades.

The Science behind the Story Are we “Turning the Tide” for Native Oysters in Chesapeake Bay? Observation: By 2001, populations of the Eastern oyster (Crassostrea virginica) had dropped by 99% in Chesapeake Bay. Study: David Schulte wanted to learn whether there was a viable approach to restoring native oysters to the bay. Schulte knew that one of the largest impacts to the native oysters was the destruction of oyster reefs. Because young oysters settle and grow on the shells of dead oysters, destruction of oyster reefs reduces recruitment. Schulte designed an experiment in which he constructed low-relief reefs, with shells piled 8-12 cm off the bottom and high-relief reefs, with shells piled 25-45 cm off the bottom. In addition, he left other sites unrestored to serve as controls for the experiment.

Results: After three years, oyster populations were sampled, and the results were remarkable. Oyster populations on the constructed reefs were significantly higher than the unrestored bottom. High-relief reefs supported 1000 oysters per square meter while low-relief reefs supported 250 oysters per square meter. In comparison, the unrestored bottom supported six oysters per square meter.

Impact: The Army Corps of Engineers, using the information gleaned from Schulte’s study, proposed an approach to Chesapeake Bay restoration. The Corps’ proposal included native oyster restoration, a temporary moratorium on oyster harvest, and enhanced support for oyster aquaculture in the bay region. By the summer of 2016, oyster populations were thriving on high-relief reefs. Low-relief reefs were also seeing impressive population growth, with some low-relief reefs accumulating enough shells to become high-relief reefs. Today, protected sites for oyster restoration are being consider throughout the bay.

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Are Fertilizers from Midwestern Farms Causing a “Dead Zone” in the Gulf of Mexico?

Observation: Large areas in the Gulf of Mexico have hypoxic conditions and are nearly devoid of life.

Study: Nancy Rabalais and other researchers monitored oxygen levels in the Gulf of Mexico at many sites near shore and in deep water. They also collected hundreds of water samples to test for nitrogen, salt, bacteria, and phytoplankton.

Finally, they observed the marine environment first hand using scuba gear.

Results: Using all their data, they were able to create a map that outlined the dead zone. In addition, they were able to make predictions about the size of the dead zone based on the flow rate of Midwestern rivers.

Impact: Rabalais and her colleagues were able to identify the cause of the Gulf of Mexico dead zone: nutrient pollution from Midwestern farms. Farming advocates and some scientists argued that the pollution could be coming from another source, such as upwelling. Upon further testing of marine sediments, Rabalais and her colleagues were able to conclusively refute these arguments. Scientists now advocate that nitrogen and phosphorus should be managed to reduce their concentration in the Gulf of Mexico. Possible solutions include restoration of wetlands along the river and the river’s delta.

Local Connections Identify the closest body of water to your area that is suffering from eutrophication. If you are unaware of one, consult Figure 5.10 or use online resources, such as the Interactive map of Eutrophication and Hypoxia created by the World Resources Institute. Which of the categories shown in Figure 5.4 would likely be the largest sources of nutrient inputs to this body of water based on the human activities in its watershed? List three approaches for controlling nutrient inputs—like those used in the Chesapeake Bay—that would be well suited for this body of water. For what human activities is the waterway used? Is it a source of drinking water for cities or irrigation water for farms? Is it used for fishing and recreation? What economically important resources or ecologically important species does the body of water support?

Class time required: ten minutes – one class period This activity could be used as a homework assignment or as an in-class activity.

Either way, it will be important to give students some guidance to begin.

If you are located near the ocean, the Eutrophication and Hypoxia map created by the World Resources Institute (www.wri.org/media/maps/eutrophication/) is an excellent resource to identify your nearest body of water suffering from eutrophication. If you are not located near the ocean, your nearest body of water 84 ..

suffering from eutrophication is likely a river or lake. Eutrophic freshwater bodies are often tracked by state or local government agencies and you may find a list of them online for your area.

To identify the likely sources of pollution for the water body, you will need to determine how water is entering the water body. For example, is it flowing through a river or creek? If so, you will need to identify the watershed. Watershed maps are available online for most large river systems. If water is entering the system through groundwater or a below-ground culvert, tracking the source will be much harder, but you can still make some inferences based on the position of the water body in the landscape.

Additional information about the water body, such as use, economic value, and ecological value, may be available online.

Calculating Ecological Footprints Acreage of lawn

Fertilizer used (lb)

Water used (gal)

Gasoline used (gal)

For the typical ¼acre lawn

.25

37

15,700

4.9

For all lawns in your hometown

Answers will vary

Answers will vary

Answers will vary

Answers will vary

For all lawns in the United States

40,500,000

5,994,000,000

2,543,400,000,000

793,800,000

1. Approximately 5,994,000,000 pounds of fertilizer are applied each year to lawns in the United States. Inorganic nitrogen-based fertilizer results from human production via the Haber-Bosch process. Much of the nitrogen is taken up by the grass, but much of it runs off and ends up in local waterways.

2. Some types of grasses require less fertilizer (and water) than others. Switching to these types or grasses or growing plants that require less fertilizer is an obvious step. Barriers or trenches to contain runoff might be another solution.

3. The number of gallons of gasoline that could be saved is 793,800,000.

Answers will vary.

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6 Ethics, Economics, and Sustainable Development Chapter Objectives This chapter will help students: Describe how culture and worldview influence the choices people make Discuss the nature and historical expansion of environmental ethics in Western culture Compare and contrast major approaches in environmental ethics Explain how our economies exist within the environment and how economies rely on ecosystem services Identify principles of classical and neoclassical economics and summarize their implications for the environment Describe aspects of environmental economics and ecological economics, including valuation of ecosystem services and full cost accounting Discuss how individuals and businesses can help move our economic system in a sustainable direction Define sustainable development and the “triple bottom line,” and discuss how sustainable development is pursued worldwide

Lecture Outline I.

Central Case Study: Costa Rica Values Its Ecosystem Services A. Today, Costa Rica has regained much of its forest cover, boasts a world-class park system, and stands as a global model for sustainable resource management.

B. A novel government program there is called Pago por Servicios Ambientales (PSA)–translated as Payment for Environmental Services.

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C. Economists have proposed creating financial incentives for conserving ecosystem services.

D. In Costa Rica, which had lost more than three-quarters of its forest, political leaders were ready to try this approach in their national policy.

E. The Costa Rican government has been paying farmers and ranchers to preserve forest on their land, replant cleared areas, allow forest to regenerate naturally, and establish sustainable forestry systems.

Payments are designed to be competitive with potential profits from farming or cattle ranching, and in recent years, these payments have averaged $78/hectare (ha)/yr ($32/acre/yr).

F. The PSA program recognizes four ecosystem services that forests provide: 1. Watershed protection: Forests cleanse water by filtering pollutants, and they conserve water and reduce soil erosion by slowing runoff.

2. Biodiversity: Tropical forests such as Costa Rica’s are especially rich in life.

3. Scenic beauty: Appreciation of scenic beauty encourages recreation and ecotourism, which bring money to the economy.

4. Carbon sequestration: Forests pull carbon dioxide from the atmosphere, thereby slowing global warming.

G. To fund the program, the government sought money from people and companies who benefited from these services.

H. Costa Rican landholders rushed to sign up for the PSA program.

I. Deforestation slowed in Costa Rica in the wake of the program; forest cover rose by 10% in the decade after 1996.

J. However, some observers argued that forest loss had been slowing for other reasons and that the program itself was having little effect.

K. In response, the government modified its policies, making the program more accessible to small farmers and targeting the payments to locations where forest is most at risk and environmental assets are greatest.

L. From a low of 17% in 1983, forest cover has risen to more than 53% today. The nation has thrived economically while protecting its environment.

M. Many factors have contributed to Costa Rica’s success in building a wealthier society while protecting its ecological assets.

N. As a result, Costa Ricans understand the economic value of protecting their natural capital.

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II.

Environmental Ethics 1. Ethics is a branch of philosophy that involves the study of good and bad, of right and wrong. The term ethics can also refer to the set of moral principles or values held by a person or a society.

A. Culture and worldview influence our decisions.

1. Every action we take affects our environment.

2. Culture can be defined as the ensemble of knowledge, beliefs, values, and learned ways of life shared by a group of people. A worldview reflects beliefs about the meaning, operation, and essence of the world.

3. People with different worldviews can study the same situation yet draw dramatically different conclusions.

B. Many factors shape our worldviews.

C. Ethical standards help us judge right from wrong. a. Some ethicists are relativists, who believe that ethics do and should vary with social context. b. Many ethicists are universalists, who maintain that there exist objective notions of right and wrong that hold across cultures and contexts. c. Ethical standards are the criteria that help differentiate right from wrong.

d. The categorical imperative is one classical ethical standard, which equates to the “golden rule.” e. Another is the principle of utility, which holds that something is right when it produces the greatest practical benefits for the most people.

D. We value things in two ways.

1. One way is to value something for the pragmatic benefits it brings us if we put it to use; this is termed instrumental value, or utilitarian value.

2. The other way is to value something for its intrinsic worth, to feel that something has a right to exist and is valuable for its own sake.

This notion is termed intrinsic value, or inherent value.

E. Environmental ethics pertains to people and the environment.

1. The application of ethical standards to relationships between people and nonhuman entities is known as environmental ethics.

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F. We have expanded our ethical consideration.

1. Many traditional non-Western cultures have long granted nonhuman entities intrinsic value and ethical standing.

2. As the history of Western cultures (European and European-derived societies) has progressed, people have granted intrinsic value and extended ethical consideration to more and more people and things.

3. Rising economic prosperity has played a role by making us less anxious about our day-to-day survival. Science has also played a role by demonstrating that people do not stand apart from nature, but rather are part of it.

4. We can simplify our continuum of attitudes toward the natural world by dividing it into three ethical perspectives. a. Anthropocentrism is a human-centered view of our relationship with the environment. b. Biocentrism ascribes intrinsic value to certain living things or to the biotic realm in general. c. Ecocentrism judges actions in terms of their effects on whole ecological systems.

G. Environmental ethics has ancient roots.

1. People have contemplated our ethical relations with nature for thousands of years.

2. Some ethicists and theologians have pointed to the religious traditions of Christianity, Judaism, and Islam as sources of anthropocentric hostility toward the environment.

3. Others interpret sacred texts of these religions to encourage benevolent human stewardship over nature.

H. The industrial revolution inspired reaction.

1. As industrialization spread in the 19th century, it amplified human impacts on the environment.

2. Some writers of the time drew attention to the drawbacks of industrialization.

3. Transcendentalism was a philosophical movement started during the 1840s in the United States by Ralph Waldo Emerson, Henry David Thoreau, and Walt Whitman.

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I. Conservation and preservation arose with the 20th century.

1. John Muir was an advocate for the preservation of wilderness.

2. Today he is associated with the preservation ethic, which holds that we should protect the natural environment in a pristine, unaltered state.

3. Gifford Pinchot is associated with the conservation ethic, which holds that people should put natural resources to use, but that we have a responsibility to manage them wisely.

J. Aldo Leopold’s land ethic inspires many people.

1. Aldo Leopold came to see that healthy ecological systems depend on the protection of all their interacting parts.

2. He argued that humans should view themselves and “the land” as members of the same community, and that we are obliged to treat the land in an ethical manner.

K. Environmental justice seeks fair treatment for all people.

1. Environmental justice involves the fair and equitable treatment of all people with respect to environmental policy and practice, regardless of their income, race, or ethnicity.

2. The struggle for environmental justice has been fueled by the recognition that poor people tend to be exposed to a greater share of pollution, hazards, and environmental degradation than are richer people.

3. A protest in the 1980s by residents of Warren County, North Carolina, in opposition to a proposed toxic waste dump in their community helped to ignite the environmental justice movement.

4. Native Americans have encountered many environmental justice issues.

5. Likewise, low-income white residents of the Appalachian region have long been the focus of environmental justice concerns.

6. Today, despite much progress toward racial equality, significant inequities remain.

7. One ongoing story involves Latino farm workers in California’s San Joaquin Valley. These workers harvest much of the U.S. food supply of fruits and vegetables, yet suffer some of the nation’s worst air pollution.

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III.

Economics and the Environment 1. An economy is a social system that converts resources into goods (material commodities manufactured for and bought by individuals and businesses) and services (work done for others as a form of business).

2. Economics is the study of how people decide to use potentially scarce resources to provide goods and services that are in demand.

A. Economies rely on goods and services from the environment.

1. Economies receive inputs (such as natural resources and ecosystem services) from the environment, process them, and discharge outputs (such as waste) into the environment. The material inputs and the waste-absorbing capacity that Earth can provide are ultimately finite.

2. These interactions are readily apparent, yet traditional economic schools of thought have long overlooked their importance.

3. The degradation of ecosystem services can weaken economies.

B. Economic theory moved from an “invisible hand” to supply and demand.

1. Known today as a founder of classical economics, Adam Smith felt that when people pursue their own economic self-interest, as long as the behavior is constrained by the rule of law and private property rights and operated within a competitive marketplace, the marketplace will behave as if guided by “an invisible hand” to benefit society as a whole.

2. Neoclassical economics examines the psychological factors underlying consumer choices.

3. The conflict between buyers and sellers results in a compromise price being reached and the “right” quantity of commodities being bought and sold. This is phrased in terms of supply, the amount of a product offered for sale at a given price, and demand, the amount of a product people will buy at a given price if free to do so.

4. To evaluate an action or decision, neoclassical economists use cost-benefit analysis, which compares the estimated costs of a proposed action with the estimated benefits.

5. Not all costs and benefits can be easily identified, defined, or quantified.

C. Neoclassical economics has environmental consequences.

1. Four fundamental assumptions of neoclassical economics often contribute to environmental degradation.

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a. Replacing resources: Resources are either infinite or largely substitutable and interchangeable. b. External costs: All costs and benefits associated with an exchange of goods or services are borne by individuals engaging directly in the transaction. i. Costs of a transaction that affect people other than the buyer or seller are known as external costs. c. Future effects are “discounted.” i. Discounting is meant to reflect how people tend to grant more importance to present conditions than to future conditions. d. Economic growth is essential for maintaining social order. i. Economic growth can be defined as an increase in an economy’s production and consumption of goods and services. ii. However, when growth becomes an end in itself, it may no longer be the best route toward well-being. Sociologists have coined a word for the way that consumption and material affluence often fail to bring people contentment: affluenza.

D. How sustainable is economic growth?

1. Our global economy is 30 times the size it was a century ago.

2. Economic growth can occur in two ways: (1) by an increase in inputs to the economy (such as more labor or natural resources) or (2) by improvements in the efficiency of production due to better methods or technologies (ideas or equipment that enable us to produce more goods with fewer inputs).

3. As our population and consumption rise, it is becoming clearer that we cannot sustain growth forever using the first approach.

4. Can we conclude, then, that human ingenuity and technology will allow us to overcome all environmental constraints and continue economic growth indefinitely? a. Answering “yes” are people sometimes referred to as Cornucopians. b. Responding “no” are people called Cassandras.

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E. Environmental and ecological economists devise strategies for sustainability.

1. Economists in the field of environmental economics believe that we can modify neoclassical economic principles to address environmental challenges and thereby attain sustainability within our current economic systems.

2. Ecological economists maintain that societies, like natural populations, cannot surpass environmental limitations. Many of these economists advocate economies that neither grow nor shrink, but rather are stable. Such a steady-state economy is intended to mirror natural ecological systems.

F. We can assign monetary value to ecosystem goods and services.

1. Ecosystem services are said to have nonmarket values, values not usually included in the price of a good or service.

2. Environmental and ecological economists have sought ways to assign market values to ecosystem services. One technique, contingent valuation, uses surveys to determine how much people are willing to pay to protect or restore a resource.

G. We can measure progress with full cost accounting.

1. For decades, policymakers and the public have assessed each nation’s economy by calculating its Gross Domestic Product (GDP), the total monetary value of final goods and services that a nation produces each year.

2. Several alternative models have been produced to account for nonmarket values and externalities; one is the Genuine Progress Indicator (GPI). To calculate GPI, we begin with conventional economic activity and add to it positive contributions not paid for with money, such as volunteer work and parenting. We then subtract negative impacts, such as crime and pollution.

3. The GPI is an example of full cost accounting (also called true cost accounting) because it aims to account for all costs and benefits. a. The Index of Sustainable Economic Welfare (ISEW) gave rise to the GPI. b. Net Economic Welfare (NEW) adjusts GDP by adding the value of leisure time and personal transactions while deducting costs of environmental degradation. c. The Human Development Index assesses standard of living, life expectancy, and education.

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4. Critics of full cost accounting argue that the approach is subjective and too easily driven by ideology.

5. Today, attempts are gaining ground to measure happiness (rather than economic output) as the prime goal of national policy. a. Bhutan is a small Asian nation that has pioneered this approach with its measure of Gross National Happiness (GNH). b. Another indicator is the Happy Planet Index, which measures how much happiness we gain per amount of resources we consume.

H. Markets can fail.

1. When markets do not take into account the positive outside effects on economies, or the negative side effects of economic activity, economists call this market failure.

I. Ecolabeling empowers consumers.

1. With ecolabeling, sellers who use sustainable practices in growing, harvesting, or manufacturing products advertise this fact on their labels, hoping to win approval from buyers.

2. In a similar vein, individuals who invest money in the stock market can pursue socially responsible investing, which entails investing in companies that have met criteria for environmental or social sustainability.

J. Businesses are responding to sustainability concerns.

1. As more consumers and investors express preferences for sustainable products and services, many industries, businesses, and corporations are “greening” their operations.

2. Some companies have cultivated an eco-conscious image from the start.

3. Today, corporate sustainability has gone mainstream, and some of the world’s largest corporations have joined in.

4. Many corporate greening efforts are more rhetoric than reality; such corporate greenwashing can mislead consumers into thinking a company is acting more sustainably than it actually is.

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IV.

Sustainable Development 1. Today’s search for sustainable solutions centers on sustainable development, economic progress that maintains resources for the future.

A. Sustainable development involves environmental protection, economic well-being, and social equity.

1. Economists use the term development to describe the use of natural resources for economic advancement.

2. Governments, businesses, industries, and organizations pursuing sustainable development aim to satisfy a triple bottom line, a trio of goals including economic advancement, environmental protection, and social equity.

3. Solutions to complex problems are never simple, and people differ in what they mean by “sustainable development.” a. Proponents of a school of thought called weak sustainability feel that we can allow natural capital to decline as long as human-made capital increases to compensate for it. b. In contrast, proponents of strong sustainability insist that human-made capital cannot substitute for natural capital and that we must not allow natural capital to diminish.

B. Sustainable development is global.

1. In 1992, the Earth Summit at Río de Janeiro, Brazil, was the world’s first major gathering focused on sustainable development, bringing together representatives from more than 200 nations.

2. In 2000, world leaders met and adopted the United Nations Millennium Declaration, which set forth eight Millennium Development Goals for humanity.

3. In 2015, world leaders meeting at the UN adopted 17 Sustainable Development Goals for humanity.

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Key Terms anthropocentrism biocentrism Cassandras classical economics conservation ethic contingent valuation Cornucopians cost-benefit analysis culture development discounting ecocentrism ecolabeling ecological economics economic growth economics economy environmental economics environmental ethics environmental justice ethical standards ethics external costs full cost accounting

Genuine Progress Indicator (GPI) greenwashing Gross Domestic Product (GDP) instrumental value intrinsic value Leopold, Aldo market failure Millennium Development Goals Muir, John neoclassical economics nonmarket values Pinchot, Gifford preservation ethic relativists services socially responsible investing steady-state economies sustainable development triple bottom line universalists worldview

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Teaching Tips 1. Assign outside readings from books that are mentioned in the chapter and discuss the authors’ views on nature and society. What has changed since these authors wrote these particular texts? What is the same? What points do the authors make that the students agree or disagree with and why? Key texts are: Walden by Henry David Thoreau, Sand County Almanac by Aldo Leopold, and The Rights of Nature by Roderick Nash.

2. Have students go to the Resources for the Future group’s website (www.rff.org) and choose one of the featured topics. Students can work in small groups or independently to present a short report to the class or to write a brief paper on the selected topic.

3. Assign an ethical perspective to each student or group of students (anthropocentrism, biocentrism, or ecocentrism) and ask them to defend that worldview in a class discussion. They should do research on that perspective before the next class. If you have a large class, ask students to be involved in an online discussion. Choose an issue for discussion—either local, national, or international—and have each student or group explain the worldview of their assigned perspective.

4. Present a local situation to your students that deals with environmental justice and/or is similar to the Costa Rican conservation program. How do the students feel about it? Have them discuss the pros and the cons of the issue.

5. Getting to Know Your Students, and the Utility of Groups a. Place your students in groups of three to six to have discussions and projects for the semester. It is a good idea to have each student in a group have a different strength pertinent to the class. One effective grouping method is to have students fill out a 3 x 5 card indicating their familiarity and comfort level with 1) biology, 2) math, 3) Internet searches, 4) PowerPoint, and 5) public speaking. It should take only 10–20 minutes to sort the cards in groups of students with different strengths: one student for biology, one for math, one for Internet use, and so on. When students enter the room for the next class, have them find their card in the group to which they’ve been assigned. b. Take used file folders and remove the tab that sticks out. This makes it easy to stand the folders up “tent” style. Have a set of these blank folders available for each group, and have each student use markers to write his or her name on BOTH sides so that everyone in the room can see it. Give the 97 ..

group a colored folder in which to keep these “name tents” and other group-related items. The colored folders can be the responsibility of a group member or, ideally, left in the classroom in a cardboard box if you have the space. Have the students use their name tents for at least the first three weeks of class to assist everyone in learning names. Research shows that students who feel more “connected” to classmates have better perseverance in specific classes and in college in general. Helping students to feel like part of a group can assist with this goal. c. If you have a digital camera, take a photo of each group, with each student holding his or her name tent. Put six or eight groups per page into Photoshop or PowerPoint and print out the sheets. You now have a way to learn the names of your students quickly. Keep the pages with you as you grade papers or lead class discussions. d. Have individuals list observable behaviors that show a person acting responsibly and respectfully toward the environment. Ask each student to create a second list of core values that might motivate such behavior. Give examples such as honesty, respect, etc. Create a master list for the class.

Hold that list until the last day of class and repeat the exercise. The list of behaviors should expand substantially. Additional core values may emerge as well.

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Additional Resources Websites 1. The International Society for Ecological Economics (www.isecoeco.org) The ISEE provides information that “facilitates understanding between economists and ecologists, and the integration of their thinking into a transdiscipline aimed at developing a sustainable world.”

2. John Muir Exhibit, Sierra Club (www.sierraclub.org/john_muir_exhibit) This online exhibit features the life of John Muir, renowned naturalist and founder of the Sierra Club.

3. Environmental Justice Resources on the World Wide Web, Working Group on Environmental Justice, Harvard University (ecojustice.net/document/ejlinks.htm) This online resource provides links to a large number of other environmental justice websites, documents, and government agencies.

4. Ethics and the Environment, University of Georgia (eande.uga.edu) This web-based journal provides an interdisciplinary forum for theoretical and practical articles, discussions, reviews, comments, and book reviews in the broad area encompassed by environmental ethics.

5. The Aldo Leopold Foundation (www.aldoleopold.org) In 1982, Leopold’s children, Starker, Luna, Nina, Carl, and Estella, all respected conservationists themselves, established the Aldo Leopold Foundation in response to the growing interest in their father’s legacy. For more than 20 years, the Aldo Leopold Foundation has promoted the care of natural resources and fostered an ethical relationship between people and land.

Audiovisual Materials 1. The Nature of Business: Partnering with the Environment, 2001, distributed by Films for the Humanities and Sciences (ffh.films.com) This program shows corporate leaders who are planning for a sustainable future by incorporating social responsibility and environmental protection into all processes and decisions.

2. The Environment: A Historical Perspective, 1999, distributed by Films for the Humanities and Sciences (ffh.films.com) Scientists, academic experts, and others study the environmental impact humans have had on the planet and present their perspectives on ecological stewardship for the 21st century.

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3. NOW with Bill Moyers, 2002, British Broadcasting Corporation, distributed by PBS video (www.pbs.org/now/science/unsummit.html) Bill Moyers and Nisha Pillai interview a panel of environmental visionaries about the global environment at the Johannesburg Earth Summit.

4. Green Pacts and Greenbacks, 2000, distributed by Films for the Humanities and Sciences (ffh.films.com) Businesspeople and environmentalists explore the business behind doing business the Earth-friendly way.

Weighing the Issues Preservation and Conservation Facts to consider: Preservationists would argue against any resource exploitation.

Answers will vary, but should focus on the inherent value of the land itself, and should seek to determine whether the value of the land would be destroyed by the development. Another likely answer would address which option would play a larger role in overall human happiness: scarring the land to exploit natural resources or keeping wild lands intact. Conservationists would be more likely to support human development to some degree. Again, student answers will vary, but may include a focus on the land use that constitutes the greatest good for the greatest number of people. Conservationists would seek to manage the resources and make them available to the largest number of people for the longest time possible. The development ethic is in direct opposition to preservationism and can work for or against conservationism because its main focus is to “master nature” and promote economic development of all resources for human use, regardless of cost or consequences. Students will have to give a personal rationale for whichever ethic they choose.

Environmental Justice Facts to consider: Answers will vary. In 1994, President Clinton issued an executive order requiring federal agencies to make sure that their environmental actions do not discriminate on the basis of income. This executive order set a precedent by expanding these directives to actions of state and local governments.

People may disagree about whether such restrictions should also apply to private entities, but other procedures can be followed that will reduce this inequality, even without such changes. For instance, public agencies can provide more vigorous enforcement of existing antipollution laws, including the levying of fines and other punishments on violators. Also, both public and private studies could be required not only to predict the environmental consequences of proposed projects, but also to assess the effect of existing facilities. Making results public would help to 100 ..

control the negative effects of environmental actions on communities. Other answers may suggest additional ways to reduce this inequality such as regulations, fines, compensation for loss due to adverse effects of environmental actions, and public education about the pros and cons of any proposed environmental action.

Cornucopian or Cassandran?

Facts to consider: Answers will vary depending on the backgrounds of your students. Students who are business, economics, computer, and technology majors will gravitate toward the Cornucopian view that technology can sustain a growing human population. Those students who are science or mathematics majors will gravitate toward the Cassandran’s view that no human technological advancement can indefinitely support endless human growth. Also, consider the students’ lifestyles and personal perspectives—if they are heavily reliant on technology to drive their lifestyles, they most likely will be associated with the Cornucopian view. If they are living a more sustainable lifestyle, they can associate with the merits of a Cassandran lifestyle. Students will invariably overlap different areas of their beliefs with the textbook definitions. But the view of the students, as stated by the first question, will drive the informed response of the last.

The Science behind the Story Do Payments Help Preserve Forests?

Observation: Some early studies were quick to credit the PSA program for saving forests. A 2006 study conducted for FONAFIFO, the agency administering the program, concluded that PSA payments in the central region of the country had prevented 108,000 ha (267,000 acres) of deforestation—38% of the area under contract. Indeed, deforestation rates fell as the program proceeded; rates of forest clearance in 1997–2000 were half what they were in the preceding decade.

Question: Have Costa Rica’s PSA payments actually been effective in preventing forest loss?

Hypothesis: Researchers hypothesized that PSA payments were not responsible for this decline and that deforestation would have slowed anyway because of other factors.

Study: To test this hypothesis, a team led by G. Arturo Sanchez-Azofeifa of the University of Alberta and Alexander Pfaff of Duke University worked with FONAFIFO’s payment data as well as data on land use and forest cover from satellite surveys. They layered these data onto maps using a geographic information system (GIS), then explored the patterns revealed.

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Results: Most researchers today hold that Costa Rica’s forest recovery results from a long history of conservation policies and economic developments. Indeed, deforestation rates had been dropping steeply before the PSA program was initiated.

Impact: To help the PSA program make better use of its money, most researchers today feel that PSA payments should be targeted.

Ethics in Economics: How Much Will Climate Change Cost?

Question: How much will it cost our society if we do nothing about global climate change? We need to respond to the growing problem of climate change. But the costs that this problem may impose on society need to be addressed. To do this, economics, ethics, and discounting all need to be factored into the solution.

Study: Primary sources on the scientific aspects of the topic were researched, and a price tag was placed on the economic consequences of these climate changes.

Results: It was concluded that climate change could decrease the GDP by the year 2200. But by investing now, with just a fraction of the GDP, our society could stabilize atmospheric gases and prevent most of the future economic losses.

However, an assumption was made—that we will be not only wealthier in the future, but better able to absorb economic costs. And the idea that the future will be discounted was questioned—can this be guaranteed? The discount rate in this article was deemed by some as being too low, forcing people today to pay too much for possible future impacts. In the end it was determined that the market should not be used to guide ethical decisions. And the report’s main message— that it is cheaper to deal with climate change now versus later—was robust to a fair amount of fluctuation in the discount rate, up to at least a rate of 1.5%. Stern concludes with the simple solution that the quicker we get going, the better off we’ll be.

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Local Connections Costa Rica isn’t the only place where forests are threatened, and it isn’t the only place where programs have been established to pay people for conserving ecological services. Name and describe several natural resources and ecosystem services that are important in your region. For each of these resources and services, assess whether it is being sustained or whether it is being degraded. How do you think each resource or service could best be conserved? Would you recommend a program of payments to provide incentives for conservation? Why or why not? What other steps might be taken to help conserve each resource or service?

Class time required: one class period To begin, have students (on their own or in small groups) name five natural resources that are important in your region. If they are struggling to identify five, they may need to use the Internet. After 5–10 minutes, have each student or group share their list with the class. As a class, identify the five most important natural resources. Assign each student or group one resource to research in depth. Have the students answer the questions in the above prompt. After 15–20 minutes, have each student or group report what he or she found to the class. At the end, facilitate a class discussion about resource conservation in your area.

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Calculating Ecological Footprints Components of GPI

U.S. total in 1950 (trillions of dollars)

Per capita in 1950 (thousands of dollars)

U.S. total in 2004 (trillions of dollars)

Per capita in 2004 (thousands of dollars)

GDP

1.153

7.6

7.589

25.9

Benefits

1.041

6.8

4.746

16.2

Environmental Costs

0.407

2.7

3.990

13.6

Social and Economic Costs

0.476

3.1

3.926

13.4

GPI

1.311

8.6

4.419

15.1

1. 6.58. 3.37. Answers may vary.

2. 4.559, 9.803, 8.248. GPI is shrinking as a proportion of GDP. Worst = environmental costs. Other answers will vary.

3. Answers will vary. Anthropocentric will be higher.

4. Answers will depend on the student.

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7 Environmental Policy: Making Decisions and Solving Problems Chapter Objectives This chapter will help students: Describe environmental policy and discuss its societal context Explain the role of science in policymaking Discuss the history of U.S. environmental policy and summarize major U.S. environmental laws List institutions that influence international environmental policy and describe how nations handle transboundary issues Compare and contrast the different approaches to environmental policymaking

Lecture Outline I.

Central Case Study: Young Americans Take on Climate Change in the Courts A. In 2015, 21 young Americans launched a landmark lawsuit, Juliana v.

United States, which asserts that federal policies promoting fossil fuel use have violated their constitutional rights to life, liberty, and property and failed to protect essential natural resources that the government should hold in trust for the public.

B. The case was scheduled to come to trial in 2018, but a last minute stay by the U.S. Supreme Court stretched the battle into 2019.

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C. Barack Obama was president when the suit was launched, butthe stakes are higher now that President Trump has initiated steps to pull out of the Paris Climate Agreement, dismantled Obama’s Clean Power Plan, and is trying to push the country back to a reliance on coal.

D. If and when a trial is held, lawyers will argue that policymakers knew the dangers of climate change and failed to act.

E. The plaintiff’s case will rely on the public trust doctrine, which holds that the government is responsible for guarding and maintaining natural resources in trust for the public.

F. The lawsuit makes clear that climate change is not just a scientific issue but a moral one, too. Juliana and her fellow plaintiffs maintain that it is ethically unacceptable if the actions (or inactions) of those in power from older generations result in a severely degraded environment and quality of life for younger and future generations.

G. The government lawyers have argued that any harm the plaintiffs may experience will have resulted from “emissions from every source in the world over decades” and that Americans are not guaranteed any particular right to particular climate conditions under the U.S. Constitution.

H. Worldwide, similar lawsuits are being initiated.

II.

Environmental Policy: An Overview 1. A policy consists of a formal set of general plans and principles intended to address problems and guide decision-making.

2. Public policy is made by governments and consists of laws, regulations, orders, incentives, and practices intended to advance societal well-being.

3. Environmental policy pertains to our interactions with our environment.

A. Environmental policy addresses issues of fairness and resource use.

1. Governments intervene in the marketplace for several reasons.

2. Environmental policy aims to protect people’s health and wellbeing, to safeguard environmental quality and conserve natural resources, and to promote equity or fairness in people’s use of resources.

3. The tragedy of the commons, as explained by Garrett Hardin, is when an unregulated resource held in common eventually becomes overused and degraded.

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4. Although public oversight through government can alleviate the tragedy of the commons, this dilemma can also be addressed in other ways, including a cooperative approach and privatization.

5. If a community agrees to reduce use or pollution in a common resource while one or two groups or individuals do not participate, they are free riders on the efforts of others; this can collapse the voluntary system, making mandated policy more effective.

6. External costs are harmful impacts suffered by people not involved in the actions that created them.

7. When governments take action to force industries to protect water quality, clean up their pollution, pay fees, or reimburse residents for damage, this helps to “internalize” costs.

8. The polluter pays principle specifies that a party responsible for pollution should be held responsible for covering the costs of its impacts.

B. Various factors can obstruct environmental policy.

1. Businesses and individuals often view regulations as restrictive, bureaucratic, or costly.

2. Another reason people sometimes do not see a need for environmental policy stems from the nature of most environmental problems, which often develop gradually.

3. However, money often wields influence over policymakers, and some people and organizations wield more influence than others.

4. The movement of individuals between government and the private sector is known as the revolving door.

C. Science informs policy but is too often disregarded.

1. In today’s world, a nation’s strength depends on its commitment to science. This is why governments devote a portion of their tax revenue to fund scientific research.

2. Unfortunately, sometimes policymakers allow ideology, rather than science, to determine policy on scientific matters.

III.

U.S. Environmental Law and Policy A. Federal policy arises from the three branches of government.

1. Legislation is created by Congress, which consists of the Senate and the House of Representatives.

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2. Legislation is enacted (approved) or vetoed (rejected) by the president, whose veto may be overridden by a two-thirds vote of Congress.

3. Regulations are specific rules or requirements intended to help achieve the objectives of the more broadly written statutory law.

4. The president may also issue executive orders, specific legal instructions for government agencies.

5. The judiciary, consisting of the Supreme Court and various lower courts, is charged with interpreting law. a. Courts interpret laws because over time social norms, societal conditions, and technologies change. b. Decisions made by the courts are known as case law. c. Previous rulings then serve as precedents, or legal guides, for later cases.

B. Courts interpret the constitutionality of policy.

1. The U.S. Constitution lays out several principles that have come to be especially relevant to environmental policy. A regulatory taking occurs when the government, by means of a law or regulation, deprives a property owner of all or some economic uses of his or her property.

C. State and local governments also make environmental policy.

1. States, counties, and municipalities all generate and enforce environmental policy of their own.

2. State laws cannot violate principles of the U.S. Constitution, and if state and federal laws conflict, federal laws take precedence.

D. States vary in their environmental policy.

1. Ideally, states and localities can act as laboratories for experimenting with novel policy concepts so that ideas that succeed may be adopted elsewhere.

E. Early U.S. environmental policy promoted development.

1. Laws enacted during the first period, from the 1780s to the late 1800s, accompanied the westward expansion of the nation and were intended mainly to promote settlement and the extraction and use of the continent’s abundant natural resources.

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a. Among these early laws were the General Land Ordinances of 1785 and 1787, by which the new federal government gave itself the right to manage the lands it was expropriating from Native Americans.

F. The second wave of environmental policy encouraged conservation.

1. In the late 1800s, as the continent became more populated and its resources became increasingly exploited, public policy regarding natural resources began to shift.

2. During this time, the government created national parks, wildlife refuges, and the national forest system.

G. The third wave responded to pollution.

1. The publication of Rachel Carson’s Silent Spring awakened the American public to the negative impacts of pesticides and industrial chemicals.

2. Ohio’s Cuyahoga River was so polluted with oil and industrial waste that the river actually caught fire a number of times.

3. Legal scholar Joseph Sax developed the public trust doctrine, which holds that natural resources such as air, water, soil, and wildlife should be held in trust for the public and that government should protect them from exploitation by private parties.

4. Today, largely because of policies enacted since the 1960s, our health is better protected and the nation’s air and water are considerably cleaner.

H. Passage of NEPA and creation of the EPA were milestones.

1. The National Environmental Policy Act (NEPA) was signed in 1970 and requires that an environmental impact statement (EIS) be prepared for any major federal action that might significantly affect environmental quality.

2. The EIS process uses a cost-benefit approach, and generally does not halt development projects while providing incentives to lessen the environmental damage resulting from a development or activity.

3. The Environmental Protection Agency (EPA) is charged with conducting and evaluating research, monitoring environmental quality, setting and enforcing standards for pollution levels, assisting the states in meeting the standards, and educating the public.

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I. The social context for policy evolves.

1. In the 1980s, Congress strengthened, broadened, and elaborated on the laws of the 1970s. Major amendments were made to the Clean Water Act in 1987 and to the Clean Air Act in 1990.

2. With each administration, the executive branch has sought to strengthen or weaken environmental regulations.

3. Today in the United States, legal protections for public health and environmental quality remain strong in some areas but have eroded in others.

J. Today’s policy debates center on climate change and equity concerns.

1. Currently, a fourth wave of environmental policy is coming to fruition. Today’s concerns center on climate change and environmental justice.

2. In 2019, the Green New Deal was proposed by U.S. Representative Alexandria Ocasio-Cortez of New York and U.S. Senator Edward Markey of Massachusetts. This non-binding congressional resolution put forth the goal of converting the U.S. power grid to 100% renewable energy, reengineering automotive technology, and reducing greenhouse gas emissions “as much as is technologically feasible” in the next 10 years.

K. Environmental policy advances today on the international stage.

IV.

International Environmental Policy A. Globalization makes international institutions vital.

1. Globalization describes the process by which the world’s societies have become more interconnected, linked by diplomacy, commercial trade, and communication technologies in countless ways.

2. Yet as globalization proceeds, societies and ecological systems are altered at unprecedented rates and scales.

B. International law includes customary law and conventional law.

1. International law, known as customary law, arises from longstanding practices, or customs, held in common by most cultures. In contrast, international law, known as conventional law, arises from conventions, or treaties (written contracts among nations), into which nations enter.

2. Treaties such as the Montreal Protocol and the Kyoto Protocol are truly global in scope and have been ratified by most of the world’s nations. However, treaties are also signed among pairs or groups of 110 ..

nations. The United States, Mexico, and Canada entered into the North American Free Trade Agreement (NAFTA) in 1994, which eliminated trade barriers such as tariffs on imports and exports to make goods cheaper to buy.

C. Several organizations shape international environmental policy.

1. The United Nations (UN) plays an active role in shaping international environmental policy by sponsoring conferences, coordinating treaties, and publishing research. An agency within it, the United Nations Environment Programme (UNEP), promotes sustainability with research and outreach activities that provide information to policymakers and scientists.

2. The World Bank is one of the largest sources of funding for economic development.

3. The European Union (EU) seeks to promote Europe’s unity and its economic and social progress and to “assert Europe’s role in the world.”

4. The World Trade Organization (WTO) represents multinational corporations and promotes free trade by reducing obstacles to international commerce and enforcing fairness among nations in trading practices.

5. A number of nongovernmental organizations (NGOs)— nonprofit, mission-driven organizations not overseen by any government—have become international in scope and exert influence over policy.

V.

Approaches to Environmental Policy A. Policy can follow three approaches.

1. Before the legislative push of recent decades, most environmental policy questions in the United States were addressed with lawsuits in the courts.

2. Most environmental laws and regulations of recent decades use a command-and-control approach in which a regulating agency prohibits certain actions—or sets rules, standards, or limits—and threatens punishment for violations.

3. The command-and-control policy has been effective.

4. Economic policy tools use financial incentives to encourage desired outcomes, discourage undesired outcomes, and set market dynamics in motion to achieve goals in an economically efficient manner.

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B. Green taxes discourage undesirable activities.

1. A tax on an environmentally harmful activity or product is called a green tax.

2. However, businesses generally pass on their tax expenses to consumers, and these increased costs may affect low-income consumers disproportionately more than high-income ones.

C. Subsidies promote targeted activities.

1. A type of economic policy tool is the subsidy, a government giveaway of money or resources that is intended to support or promote an industry or activity. A tax break is a common form of subsidy.

2. Many environmentally harmful subsidies exist.

D. Emissions trading uses markets.

1. Another approach that employs market dynamics to achieve policy goals is emissions trading. In an emissions trading system, a government creates a market in permits for the emission of pollutants, and companies, utilities, or industries then buy and sell the permits among themselves. In a cap-and-trade emissions trading system, the government first caps the overall amount of pollution it will allow, then grants or auctions off permits to polluters that allow them each to emit a certain fraction of that amount. As polluters trade these permits, the government progressively lowers the cap of overall emissions allowed.

2. By providing firms with an economic incentive to reduce pollution, emissions trading can lower expenses for both industry and the public relative to a conventional regulatory system.

3. Although cap-and-trade programs can reduce pollution, they do allow hotspots of pollution to occur around plants that buy permits to pollute more. Moreover, large firms can hoard permits, deterring smaller new firms from entering the market, thereby suppressing competition.

4. Emissions trading programs need to be carefully designed to be effective.

E. Market incentives are diverse at the local level.

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Key Terms cap and trade command and control conventional law customary law emissions trading environmental impact statement (EIS) environmental policy Environmental Protection Agency (EPA) European Union (EU) executive orders free rider globalization green tax hydraulic fracturing legislation

National Environmental Policy Act (NEPA) nongovernmental organizations (NGOs) policy polluter pays principle public policy public trust doctrine regulations regulatory taking revolving door shale gas subsidy tragedy of the commons United Nations (UN) World Bank World Trade Organization (WTO)

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Teaching Tips 1. The chapter briefly describes the major impacts of hydraulic fracturing.

Discuss these impacts in more detail in class and ask the students to rank those impacts in order of importance to them. Is human health most important? The economy? The environment?

2. Assign students to read Garrett Hardin’s paper, “The Tragedy of the Commons,” published in Science 162:1243–1248. Ask them to answer the following questions: a. Why does the “economic man” behave differently in a commons than on private property? b. What are the implications of this behavior on public lands? c. Ask students to conduct Internet research for updates on the fracking in Dimock, Pennsylvania. In your opinion, is this a tragedy of the commons?

3. Discuss some of the environmental laws that were passed in the late 1960s and early 1970s to emphasize that the “third wave of U.S. environmental policy responded largely to pollution problems.” The Clean Water Act; the Clean Air Act; the Federal Insecticide, Fungicide, and Rodenticide Act; and the Wilderness Act are just a few. Summaries of the major environmental statutes are available on the U.S. EPA website (www.epa.gov/epahome/laws.htm).

4. Ask students to create a concept map that illustrates the three branches of the federal government and the components of each. Concept maps graphically illustrate relationships among pieces of information. Maps can be drawn by hand or designed using computer software such as Inspiration. For more information about concept mapping, see www.inspiration.com.

5. Monitor the local news, print, broadcast, and Web outlets to learn if there are any local environmental issues that are of concern to a wide range of individuals. Have students research the topic and use the steps outlined in the text for the environmental policy process. The goal of this exercise is to create a flow chart that will culminate with “shepherding a solution into law,” as per the text.

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Additional Resources Websites 1. Major Environmental Laws, U.S. Environmental Protection Agency (www.epa.gov/laws-regulations) This resource provides full text and summaries of the major environmental laws.

2. NEPA: Project Development Process, U.S. Department of Transportation Federal Highway Administration (environment.fhwa.dot.gov/index.asp) This listing is an overview of NEPA and its impacts on projects planned by the Federal Highway Administration.

Audiovisual Materials 1. Motor, 2000, video distributed by Bullfrog Films (www.bullfrogfilms.com/catalog/motor.html) This video is a summary of the controversy surrounding the use of off-road vehicles on public lands.

2. The God Squad and the Case of the Northern Spotted Owl, 2001, video distributed by Bullfrog Films (www.bullfrogfilms.com/catalog/gsquad.html) In this video, the God Squad investigates the Endangered Species Committee proceedings that selected economic interests over the survival of a species.

3. Gasland, 2010, video distributed by HBO (www.hbo.com/documentaries/gasland/index.html) This controversial documentary investigates the impact on communities from natural gas drilling, specifically via hydraulic fracturing.

4. Poisoned Waters, 2009, FRONTLINE, a registered trademark of WGBH Educational Foundation (www.pbs.org/wgbh/pages/frontline/poisonedwaters) The beginning of this documentary has a summary of the waves of environmental policy, including the Cuyahoga River burning.

5. Strange Days on Planet Earth, 2005, National Geographic, distributed by PBS (www.pbs.org/strangedays) This program examines the cause-and-effect relationship between what we as humans do to Earth and what that does to our environment and ecosystems.

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Weighing the Issues Internalizing External Costs Facts to consider: First, internalizing all costs associated with a product is very difficult, and with all of the pollution generated through extraction, processing, refining, and distribution of crude oil and gasoline, $13 a gallon seems to be a deal. However, this price would send shockwaves throughout the United States, which is used to cheap fuel. Both driving techniques and types of vehicles purchased would tend toward the most fuel efficient, which is better for the environment. Vehicles produced would also be fuel efficient because that is what the consumer would be demanding, and energy resources might stray from fossil fuels, owing to the cost. Taxes could increase with the prices, but health insurance premiums could go down because pollution-related illness could decrease.

Although this might cost more in the long run, this might be a cost worth paying.

Green States and Brown States Facts to consider: There isn’t a definition of brown or green states. All states enact environmental laws, but some states are leaders in environmental legislation.

Environmental policy can include everything from land conservation, to limits on air and water pollution, to regulations on resource use and extraction. It is important to recognize that regional characteristics may drive certain environmental policies. For example, policies related to water use may be more important in dry climates such as the Southwestern United States, while policies related to air pollution may be more important in areas with a high population density such as along the U.S. east and west coasts.

Trade Barriers and Environmental Protection Facts to consider: There is actually an example of this in practice involving the United States and Mexico. The United States’ main tuna companies sell dolphinsafe tuna, caught by more environmentally friendly practices. Through NAFTA, Mexico is able to sell tuna to corporations in the United States. However, the problem comes in when Mexican tuna fisherman do not use the same environmentally friendly practices, then sell tuna to U.S. companies that still label it as dolphin safe. This doesn’t seem environmentally ethical. But it allows Mexican-caught tuna to be sold on the U.S. market, boosting the economy of that country. Answers will vary.

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A License to Pollute?

Facts to consider: As stated in the chapter, in a cap-and-trade emissions trading system, the government first determines the overall amount of pollution it will accept, and then issues permits to polluters that allow them each to emit a certain fraction of that amount. Polluters may buy, sell, and trade these permits with other polluters. In this regard, a pro is that an overall pollution limit is established. A con is that a cap is not necessarily issued to each individual polluter—the more they are willing to spend, the more that one company can pollute. In a commandand-control approach, a regulating agency prohibits certain actions, or sets rules, standards, or limits, and threatens punishment for those who violate these terms.

The pro is that a company cannot pay to pollute more—these companies would be penalized by the rules, standards, limits, etc., just as any other company. The con is that this would be much harder to regulate.

The Science behind the Story What Does the Science on Climate Change Tell Us? Observation: For many years, large groups of scientists have been pooling their expertise, summarizing their results, and presenting them to policymakers. The highest profile efforts are by the Intergovernmental Panel on Climate Change (IPCC). The reports generated by the scientists make it abundantly clear that temperatures are warming, that climate is changing, and that these changes result primarily from greenhouse gases emitted through fossil fuel burning. Research also shows that climate disruption is having ecological, social, and economic impacts.

Significance: These data can be used for legal purposes, such as the Juliana v.

United States case. The main issue is how these climate impacts would personally affect the lives of the plaintiffs.

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Local Connections What policies or actions have the policymakers in your city, region, or state considered to address greenhouse gas emissions and climate change? Has your state set any emissions targets or enacted any renewable energy mandates? Are there regulations for energy efficiency in buildings or appliances in your state?

Give at least one example of a climate change–related policy that has been enacted at your local, regional, or state level, and one example of a policy that has failed to be enacted. What results have come about from any enacted policies? What steps would you like to see your state take in terms of policy relating to climate change?

Class time required: one class period or could be completed as a homework assignment This activity could be completed in class or as a homework assignment. Either way, before they get started, it would be important to discuss the different levels of legislation, from local to state, that students may want to investigate. Legal statutes are generally very difficult for students to understand, so it may be wise to direct them to secondary sources, such as newspaper articles, for much of their research.

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Calculating Ecological Footprints Costs and benefits of major U.S. federal regulations, 2005–2015 (in billions of dollars) Agency

Benefits

Costs

Benefits minus costs

Benefit–cost ratio

Department of Energy

29.8

9.9

19.9

3.0

Department of Health and Human Services

18.8

4.1

14.7

4.6

Department of Transportation

31.6

12.1

19.5

2.6

Environmental Protection Agency (EPA)

450.8

59.5

391.3

7.6

Other Departments

85.2

22.6

62.6

3.8

Total

616.2

108.2

508.0

5.7

1. None of the regulations exerts more costs than benefits; all regulations provide more benefits than costs.

2. The EPA has the greatest excess of benefits over costs, and the greatest ratio of benefits to costs.

3. 73%. Answers will vary.

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8 Human Population Chapter Objectives This chapter will help students: Describe the scope of human population growth Discuss divergent views on population growth Explain how human population, affluence, and technology affect the environment Explain the fundamentals of demography Describe the concept of demographic transition Explain how family planning, the status of women, and affluence affect population growth

Lecture Outline I.

Central Case Study: Will China’s New “Two-Child Policy” Diffuse Their Population “Time Bomb”?

A. The People’s Republic of China is the world’s most populous nation, home to one-fifth of the more than 7 billion people living on Earth.

B. When Mao Zedong’s leadership began six decades ago, improved food production and distribution and public health allowed China’s population to swell, causing environmental problems. The average Chinese woman gave birth to 5.8 children in her lifetime.

C. The government decided to institute a population control program that prohibited most Chinese couples from having more than one child.

D. The program began with outreach efforts encouraging people to marry later and have fewer children, and increasing the accessibility of contraceptives and abortion.

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E. In 1979, the government decided to institute a system of rewards and punishments, enforcing a one-child limit per family.

F. The one-child program applied mostly to families in urban areas. Many farmers and ethnic minorities in rural areas were exempted because success on the farm often depends on having multiple children.

G. The nation’s growth rate is now down to 0.5%, and Chinese women now have an average of only 1.7 children in their lifetimes.

H. However, the one-child policy also produced a population with a shrinking labor force, increasing numbers of older people, and too few women.

I. Faced with the prospect of continued population issues, the Chinese government announced in October 2015 that the former one-child policy would immediately become a two-child policy, and couples would be permitted to have two children without penalty.

II.

Our World at Nearly Eight Billion A. The human population is growing rapidly.

1. Our global population is now more than 7.7 billion and grows by more than 80 million people each year.

2. Our unprecedented growth is due to exponential growth.

3. Rates of annual growth vary greatly from region to region and are typically higher in developing nations.

4. At a 1.2% annual growth rate, our population doubles in size in just 58 years.

B. Is population growth a problem?

1. Our spectacular growth in numbers has resulted largely from technological innovations, improved sanitation, better medical care, increased agricultural output, and other factors that have brought down death rates. a. These improvements have been particularly successful in reducing infant mortality rates, the frequency of children dying in infancy.

2. The environment has a carrying capacity for our species, just as it does for every other. We have repeatedly raised this carrying capacity by developing technology to overcome the natural limits on our population growth.

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3. The most conservative estimates of carrying capacity range from 1–2 billion people living prosperously in a healthy environment to 33 billion living in extreme poverty in a degraded world of intensive cultivation without wild natural areas.

4. In the past, population growth was universally regarded as a good thing. However, British economist Thomas Malthus (1766–1834) had a different view.

5. In our day, biologists Paul and Anne Ehrlich of Stanford University have been called “neo-Malthusians” because they too have warned that our population may grow faster than our ability to produce and distribute food.

6. Population growth has indeed contributed to famine, disease, and conflict—but as we shall see, enhanced prosperity, education, and increasing gender equality have also helped to reduce birth rates.

7. Under the Cornucopian view that many economists hold, population growth poses no problem if new resources can be found or created to replace depleted ones. In contrast, environmental scientists recognize that not all resources can be replaced.

C. Population is one of several factors that affect the environment.

1. The IPAT model represents how our total impact (I) on the environment results from the interaction among population (P), affluence (A), and technology (T): I = P  A  T. 2. A sensitivity factor (S) can be added to the equation to denote how vulnerable a given environment is to human pressures: I = P × A × T × S. 3. Impact can generally be boiled down to either pollution or resource consumption.

4. One reason our population has kept growing, despite limited resources, is that we have developed technology—the T in the IPAT equation—to increase efficiency, alleviate our strain on resources, and allow the human population to expand further.

III.

Demography 1. The application of principles from population ecology to the study of statistical change in human populations is the focus of demography.

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A. Demography is the study of human population.

1. Demographers study population size, density, distribution, age structure, sex ratio, and rates of birth, death, immigration, and emigration of people.

2. Population size is the absolute number of individuals.

3. People are distributed unevenly over our planet. a. This uneven distribution means that certain areas bear more environmental impact than others. b. At the same time, some areas with low population density are sensitive and thus especially vulnerable to impact.

4. Age structure diagrams show the relative number of people in each age class and are especially valuable to demographers in predicting future dynamics of human populations. a. A large concentration of individuals in young age groups portends a great deal of reproduction.

5. The ratio of males to females, the sex ratio, can also affect population dynamics. a. The naturally occurring sex ratio in human populations at birth features a slight preponderance of males. This slightly uneven sex ratio at birth may be beneficial to some species. However, a greatly distorted ratio can lead to problems.

B. Birth and death rates drive population change.

1. The relative rates of births to deaths determines whether a population grows, shrinks, or remains stable.

2. Historically, birth and death rates were similar, resulting in very slow population growth.

3. Today, technological advances have led to a dramatic decline in human death rates and a reduction in infant mortality rates.

4. In recent decades, falling growth rates in many countries have led to an overall decline in the global growth rate. This growth rate has declined partially because of a steep drop in birth rates.

C. Populations also change with immigration and emigration.

1. Immigration and emigration play increasingly important roles in population change in our modern, international world.

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D. Total fertility rate influences population growth.

1. The total fertility rate (TFR) is the average number of children born per woman during her lifetime.

2. Replacement fertility is the TFR that keeps the size of a population stable.

3. Factors such as industrialization, improved women’s rights, and quality health care have driven TFR downward in many nations in recent years. a. In 2016, Europe’s overall annual rate of natural increase (also called the natural rate of population change)—change due to birth and death rates alone, excluding migration—was between 0.0% and 0.1%.

E. Many nations are experiencing the demographic transition.

1. Life expectancy is the average number of years that an individual in a particular age group is likely to continue to live.

2. Demographic transition is a model of economic and cultural change that explains the trend of declining death and birth rates that has occurred when Western nations became industrialized. a. The first stage, the preindustrial stage, is characterized by conditions in which both death rates and birth rates are high. b. In the next stage, the transitional stage, death rates decline and birth rates remain high. c. The industrial stage creates employment opportunities, particularly for women, causing the birth rate to fall. d. In the final stage, the postindustrial stage, both birth and death rates have fallen to low and stable levels.

F. Is the demographic transition inevitable?

1. This transition has occurred in many European countries, the United States, Canada, Japan, and several other developed nations over the past 200–300 years. On the other hand, some developing nations may already be suffering too much from the impacts of large populations to replicate the developed world’s transition, a phenomenon called demographic fatigue.

2. Whether developing nations (which include the vast majority of the planet’s people) pass through the demographic transition is one of the most important and far-reaching questions for the future of our civilization and Earth’s environment.

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G. Will China and India complete the demographic transition?

1. Most experts predict that China will settle into a stable, postindustrial society with minimal population growth in the next several decades.

2. It is less clear whether India will complete the transition or if the impacts of demographic fatigue will derail the process.

IV.

Population and Society A. Family planning slows population growth.

1. Family planning is the effort to plan the number and spacing of one’s children. An important component of family planning is birth control, the effort to control the number of children a woman bears by reducing the frequency of pregnancy. Birth control relies on contraception, the deliberate attempt to prevent pregnancy despite engaging in sexual intercourse.

2. Low usage rates for contraceptives in some societies are caused by limited availability, especially in rural areas. In others, low usage may be due to religious doctrine or cultural influences that hinder family planning, denying counseling and contraceptives to people who might otherwise use them.

3. In a physiological sense, access to family planning (and the civil rights to demand its use) gives women control over their reproductive window, the period of their life, beginning with sexual maturity and ending with menopause, in which they may become pregnant.

B. Family-planning programs are working around the world.

C. Empowering women reduces fertility rates.

1. Studies show that where women are freer to decide whether and when to have children, fertility rates fall, and children are better cared for, healthier, and better educated.

2. Another benefit of equal rights for women is the ability to make reproductive decisions themselves.

3. Expanding educational opportunities for women is an important component of equal rights.

D. Fertility decreases as people become wealthier.

1. Poorer societies tend to show higher population growth rates than do wealthier societies.

2. Economic factors are tied closely to population growth. Poverty 125 ..

exacerbates population growth, and rapid population growth worsens poverty.

E. Expanding wealth can escalate a society’s environmental impacts.

1. Poverty can lead people into environmentally destructive behavior, but wealth can produce even more severe and far-reaching environmental impacts.

2. Individuals from affluent societies leave considerably larger per capita ecological footprints.

3. The richest 20% of the world’s people uses 86% of the world’s resources.

4. Our global footprint exceeds Earth’s capacity by 50% worldwide.

Key Terms biocapacity birth control contraception demographers demographic fatigue demographic transition demography family planning industrial stage infant mortality rates

IPAT model life expectancy Malthus, Thomas postindustrial stage preindustrial stage rate of natural increase replacement fertility reproductive window total fertility rate (TFR) transitional stage

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Teaching Tips 1. The Population Connection is the new name for the organization that used to be called Zero Population Growth (ZPG). Its website (www.populationconnection.org) has a variety of fact sheets and programs, including a campus outreach program for colleges and universities. The organization will also present free workshops and trainings at your location and at conferences.

2. Ask each student to adopt a country and research the status of its population including size, crude birth rate, crude death rate, life expectancy, infant mortality, annual growth rate, and age structure. Current information can be found on the People Facts site at www.os-connect.com/pop.

To make this an interactive activity, require each student to present the information to the class. Once presentations have been made, discuss the similarities and differences among the countries. This can lead to a discussion of the characteristics of “developed countries” versus “developing countries.”

3. Death rates have dramatically declined in the United States over the past 100 years. To examine this change in greater detail, students can conduct a study on percent survival. First, students will collect data from a local cemetery (preferably one in which people were buried before 1900) and compare those data to data from current newspaper obituary pages. Ask each student to record the age at death for 20 individuals from each source. Students will then organize the data according to 10-year age categories as shown below. There will be two tables—one for cemetery data and the other for obituary data. Percent survival is then calculated for each age category.

Age group

Number that died

Percent surviving

0–10

A

= (20 – A)/20  100

11–20

B

= [20 – (A + B)]/20  100

21–30

C

31–40 41–50 51–60 61–70 71–80 81–90 91–100 Over 100

D E F G H I J K

= [20 – (A + B + C)]/20  100 etc.

= [20 – (sum of A    K)]/20  100 127

..

The resulting percent survival values can be graphed to show a survivorship curve, with age classes on the x axis and the percent surviving values on the y axis. In general, there are three classes of survivorship curves: Type I, Type II, and Type III. A quick Internet search will find many websites explaining the three classes (mathworld.wolfram.com/SurvivorshipCurve.html).

4. Use resources from the Population Reference Bureau (www.prb.org) for classroom presentations and activities. The graphics bank contains more than 100 PowerPoint slides with illustrations of population data. The graphics cover international population and health topics (family planning, HIV/AIDS, population trends, and so on). The website also links to the Center for Public Information on Population Research, the Interagency Gender Working Group, and the Population and Health InfoShare website. The link to the World Population Data Sheet contains the latest population estimates, projections, and other key indicators for 200 countries.

5. Initiate a discussion with these questions: “Have you made any decisions regarding children in your future?” “Has any information you’ve learned this term caused you to reconsider future plans for careers, family, or places that you might choose to live?” By framing these questions as open-ended and exploratory rather than accusatory, often very productive, insightful, and engaging discussions are possible. It is essential that ground rules for a critical-thinking classroom be set prior to discussions that contain sensitive topics. Ground rules include: a safe space to share and reflect on what is offered by others; disagree with a person’s viewpoint, but remain respectful of the person who owns that viewpoint; and remain open-minded to the views of others by being a good listener.

6. Whether your course is small or large, handing out lecture notes, assignments, graded papers, and the like take up valuable class time. Here are some tips to minimize that time. a. Use two magazine/periodical files and an inbox. Label the file boxes “Past Handouts” and “Graded Papers,” and place them on a table or counter near the door. b. Put any handouts for the current day on the table in front of the boxes. c. Students bring assignments to the table and place them in the inbox. If any students missed the last session, they can get the materials from the Past Handouts box. They can check the Graded Papers box for prior assignments you have handed back, and they can pick up today’s handouts in class. d. At the end of class, pick up the day’s handout, place it in a labeled folder, and put it in the Past Handouts box. Pick up any new student assignments from the inbox. Place the boxes in a cabinet or drawer until the next session.

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e. You need an additional Graded Papers box for each section of a course.

The Past Handouts box is the same, and you will empty the inbox at the end of each class. f. If the class is larger than 50 students, you may find it easier to have several Graded Papers boxes and several inboxes, labeled A–B, C–D, E–J, etc. indicating students’ last names. Spread the sets of boxes out around the perimeter of the classroom in a standard fashion so that students know where their cohort’s box is located. g. Remind students as necessary that they can access the boxes before class, during a break, or after class, but that riffling through the boxes during class time is not desirable.

Additional Resources Websites 1. 7 Billion–Where Do You Stand?, 2014, Population Connection (www.worldof7billion.org/wp-content/uploads/2014/08/7-Billion-Where-doyou-Stand.pdf) This activity allows the students to weigh in on different topics related to the contemporary world population.

2. US Census Bureau (www.census.gov) This gateway provides population clocks for the United States and the world, along with information about births, fertility, deaths, and migration in the United States.

3. State of the World Population, United Nations Population Fund (www.unfpa.org/swp) This is a report by the United Nations Population Fund, the world’s largest international source of funding for population and reproductive health programs. Access to databases, maps, graphs, and previous years’ reports is available.

4. The World Clock, Poodwaddle (www.poodwaddle.com/worldclock) This interactive population clock allows students to see population impact on a variety of factors.

5. Carrying Capacity Network (www.carryingcapacity.org) This organization provides sobering analyses of the global human population dynamic. Topics include revisiting the demographic transition model, foreign aid, and the future of agriculture in meeting human nutrition needs.

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Audiovisual Materials 1. World in the Balance: The Population Paradox, 2004, NOVA, PBS

(www.pbs.org/wgbh/nova/worldbalance) NOVA investigates the impact of forces that are radically changing populations in both rich and poor nations.

2. Not the Numbers Game, 1997, video produced by Emily Marlow and Jenny Richards for Television Trust for the Environment and distributed by Bullfrog Films (www.bullfrogfilms.com) This six-part series looks at how women are solving population and development problems in Bosnia, Cambodia, India, Indonesia, Peru, and Uganda.

3. Population Six Billion, 1999, video distributed by Films for the Humanities and Sciences (www.films.com) This program addresses life in developing nations while providing case studies of population control initiatives in Vietnam, Uganda, and Mexico that include family planning, HIV/AIDS testing and counseling, and sex education.

4. Paul Ehrlich and The Population Bomb, 1996, video distributed by Films for the Humanities and Sciences (www.films.com) Based on Ehrlich’s book The Population Bomb, this program features archival footage from around the world as well as interviews with Ehrlich, his colleagues, and his critics.

Weighing the Issues China’s Reproductive Policy Facts to consider: The benefits of a reproductive policy such as China’s might include a greater ability to provide food, health care, housing, and education as well as reduced environmental pressure. Problems might include social and legal punishment for people who do not follow the policy; reduction in personal choice about family decisions; pressure to favor one gender over another; and pressure on industry, government finances, health care, families, and military forces because fewer working-age people are available. Alternative ways of dealing with the resource demands of a quickly growing population include finding new resources to replace depleted ones, both within the country and abroad (which may greatly increase environmental pressure as resources become increasingly scarce); using rewards for smaller families while refraining from punishments; and using more efficient technologies to reduce resource-intensive processes and pollution.

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What Are the Consequences of Low Fertility?

Facts to consider: A below-replacement fertility rate means that the population is aging. Changes in the age composition of the population will alter patterns of consumption. Most notably, an increase in the mean population age will trigger an increasing demand for health care services. Working-age people will need to supply the productivity and finances required to support the higher proportion of older, retired people. Further observations may also be mentioned, based on a broader student understanding of economics and social issues.

Students may discuss increased immigration to provide a labor force; a reduced labor force, leading to wage increases and inflation, thus decreasing the purchasing power of retirees; greater savings rates as families spend less on dependents; lower savings rates as older people, lacking income, spend their savings; and increases in the retirement age so as to reduce the demands on public welfare, as fewer younger workers are putting in funds while more older workers receive entitlements and services.

Should the United States Abstain from International Family Planning?

Facts to consider: The first of these questions requires an individual response.

The second question also requires a personal response, but students can approach it from a consumption/tragedy of the commons perspective. In responding to the final question, students may use some examples from the textbook, such as increased education and the availability of contraceptives; fewer punitive measures and more positive incentives to adhere to government policy; international monitoring groups to ensure that funds are used according to treaties; and measures assuring that actions taken by those in charge of family planning do not discriminate or penalize minority ethnic groups.

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The Science behind the Story Measuring Our “Human Footprint”: A Roadmap to Sustainability and Prosperity?

Observation: The growing global population is putting added demands on natural systems.

Question: Can we quantify and map human stresses on the environment using the human footprint?

Study: In 2016, a team from the University of Northern British Columbia, led by Oscar Venter, set out to update the Human Footprint Map first published in 2002.

To produce the updated Human Footprint Map, the team used cumulative threat mapping that combined satellite imaging and ground-based surveys to detect changes in land use.

Results: The team showed that human stresses on the environment were widespread, intense, and had increased overall since 1993. The team also found that as an area’s suitability for agriculture increased, so did the degree of human stresses on the area. There were also some signs of hope. While the global population increased by 23% and the global economy grew by 153%, the global human footprint increased by only 9% from 1993–2009. This indicates that many nations had found a way to continue to grow their populations and their economies without a corresponding increase in stress to the environment. Nations that showed a reduced stress on the environment tended to have a high score for human development and urbanization, and they tended to have a functioning, objective government.

Did Soap Operas Reduce Fertility in Brazil?

Observation: Over the past 50 years, the South American nation of Brazil experienced the second-largest drop in fertility among developing nations with large populations. It was accomplished without governmental policies that advocated controls on its citizens’ reproduction.

Hypothesis: In essence, these programs provided a model family for Brazilians to emulate—with small family sizes being a key characteristic.

Study: By combining data on Rede Globo broadcast range with demographic data, the researchers were able to compare changes in fertility patterns over time in areas of Brazil that received access to novelas with areas in Brazil that did not.

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Results: The team found that women in areas that received the Globo signal had significantly lower fertility than those in areas not served by Rede Globo, and they also found that fertility declines were age-related, with substantial reductions in fertility occurring in women aged 25–44, but not in younger women. The researchers determined that access to television alone did not depress fertility.

Local Connections The U.S. Census Bureau provides demographic statistics, based on census data, on its website for every U.S. state and county. Look up the county and state where you currently live and compare its current population with its population 10 years ago. Did your county and state increase or decrease in population? Based on your experiences or research, propose two or three reasons why your county showed the population change patterns it did. Do the same for your state. What sort of population change pattern would you prefer for where you live, more people or fewer? With your classmates and friends, share your explanations on why population changed in your state and your opinions on local population change.

Do your classmates and friends share your conclusions and opinions on local population changes, or do their thoughts on local population changes differ from yours?

Class time required: one class period Allow students to work in groups or by themselves to research the changes in population in their county and state. After collecting their data, allow students to discuss the questions in the prompt in small groups or as a class. This activity may bring up some interesting economic issues related to changes in population. For example, students may have noticed rent prices rising if they live in an area currently undergoing a population increase.

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Calculating Ecological Footprints

Nation

Brazil China Ethiopia France India Japan Mexico Russia United States

Population (millions of people)

Affluence (per capita income)

202.8 1364.1 95.9 64.1 1296.2 127.1 119.7 143.7

$15,900 $13,130 $1,500 $39,720 $5,760 $37,920 $16,710 $24,710

Personal Impact (per capita footprint, in hectares/ person) 3.1 3.7 1.1 4.7 1.1 4.7 2.5 5.6

317.7

$55,860

8.4

Total Impact (national footprint, in millions of hectares) 628.7 5047.2 105.5 301.3 1425.8 597.4 299.3 804.7 2668.7

1. See the rightmost column above.

2. The graph would show a strong positive correlation because affluence has resulted in resource consumption.

3. The graph would show a positive correlation, but not a very strong one, because affluence as well as population drives total impact.

4. The graph would show a positive correlation, but not a very strong one, because population as well as affluence drives total impact. The United States has an extremely high total impact because it has one of the largest populations in the world and because it is one of the most affluent nations in the world.

5. As one of many possible examples, coal-fired power plants have increased air pollution in the United States, but scrubbers and clean-coal technologies are now reducing pollution from these plants.

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9 The Underpinnings of Agriculture Chapter Objectives This chapter will help students: Survey the factors that underpin agriculture, and outline how agriculture has developed Explain the importance of soils to agriculture, and discuss the fundamentals of soil science Describe how farmers supply water to crops, and explore sustainable alternatives Describe how farmers supply nutrients to crops, and assess sustainable alternatives Explain the importance of pollinators for crop success, and identify ways of assisting pollinators Analyze the causes and impacts of soil erosion and land degradation, and discuss solutions Summarize major policy approaches for conservation in agriculture

Lecture Outline I.

Bees to the Rescue: By Helping Pollinators, Farmers Help Themselves A. By protecting and nurturing the bees that pollinate his almond trees in California’s San Joaquin Valley, Lakhy Sran has enabled his family business to thrive.

B. Intensive industrial farming using pesticides, fertilizers, irrigation, and unsustainable soil management has degraded the landscape and polluted the area’s soil, water, and air.

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C. Bees, flies, butterflies, and other insects pollinate more than 150 food crops, helping flowering plants produce fruits, vegetables, nuts, and seeds.

D. Many pollinators are in steep decline. They have lost habitat and the diverse flowering resources they need as industrialized productions has extended vast single-crop fields across the landscape.

E. Pollinators are also killed accidentally by the application of chemical insecticides.

F. Weakened pollinators are more susceptible to pathogens and diseases.

G. To provide bees with pollen and nectar sources throughout the season, Sran Family Orchards planted 24 acres of hedgerows filled with 13 species of native flowering shrubs and wildflowers that bloom at different times of the year.

H. Sran Family Orchards also uses no chemical pesticides and has installed a drip irrigation system to reduce water usage.

I. Because of their efforts, Sran Family Orchards became the first grower to win designation as a bee-friendly farm from Bee Better Certified, spearheaded by the Xerces Society.

J. The Xerces Society, the leading nonprofit organization dedicated to the conservation of invertebrate animals, has helped hundreds of farmers and ranchers restore nearly 700,000 acres of land to pollinator-friendly conditions.

K. Bee City USA and Bee Campus USA are programs that encourage communities and campuses to create sustainable habitats for pollinators.

II.

Resources and Services for Agriculture A. Natural resources and ecosystem services underpin agriculture.

1. Agriculture is the practice of raising crops and livestock for human use and consumption.

2. We obtain most of our food and fiber from cropland—land used to raise plants for human use.

3. Rangeland, or pasture, is land used for grazing livestock.

4. Growing crops and raising animals require inputs of resources.

Crops require soil, sunlight, water, nutrients, and mechanisms for pollination. Livestock require food and water.

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B. Agriculture has industrialized.

1. For thousands of years, the work of cultivating, harvesting, storing, and distributing crops was performed by human and animal muscle power, along with hand tools and simple machines—an approach known as traditional agriculture.

2. Farmers replaced horses and oxen with machinery that provided faster and more powerful means of cultivating, harvesting, transporting, and processing crops. Such industrial agriculture also boosted yields by intensifying irrigation and introducing synthetic fertilizers while the advent of chemical pesticides reduced competition from weeds and herbivory by crop pests. a. The use of machinery created a need for highly organized approaches to farming, leading large-scale farmers to plant vast areas with single crops in straight orderly rows. Such monocultures (“one type”) are distinct from the polycultures (“many types”) typical of traditional agriculture, such as Native American farming systems, which mixed maize, beans, squash, and peppers in the same fields.

3. Beginning around 1950, the Green Revolution introduced new technology, crop varieties, and farming practices to the developing world.

C. Sustainable agriculture safeguards resources and services.

1. Sustainable agriculture describes agriculture that maintains the healthy soil, clean water, pollinators, and other resources essential to long-term crop and livestock production.

III.

Soil: A Foundation of Agriculture A. Soil is a living system.

1. Soil is a multifaceted system consisting of disintegrated rock, organic matter, water, gases, nutrients, and microorganisms.

B. Soil supports agriculture.

1. Plants depend on soil for growth. Soil supports plants and provides them with nutrients and water.

2. Plants depend on living organisms in the soil. In particular, many fungi form symbiotic mutualistic associations with plant roots, called mycorrhizae.

C. Soil forms slowly.

1. Parent material is the base geological material in a particular location. Bedrock is the mass of solid rock that makes up Earth’s crust. Parent material is broken down by weathering, the physical, 137 ..

chemical, and biological processes that convert large rock particles into smaller particles.

2. Once weathering has produced fine particles, biological activity contributes to soil formation through the deposition, decomposition, and accumulation of organic matter. a. Partial decomposition of organic matter creates humus, a dark, spongy, crumbly mass of material made up of complex organic compounds.

3. Weathering and the accumulation and transformation of organic matter are influenced by five main factors: climate, organisms, topography, parent material, and time.

4. Because forming just 1 inch of soil can easily require hundreds or thousands of years, we would be wise to conserve the soil we have.

D. A soil profile consists of horizons.

1. As wind, water, and organisms move and sort the fine particles that weathering creates, distinct layers of soil eventually develop. Each layer is known as a soil horizon, and the cross-section as a whole, from surface to bedrock, is known as a soil profile.

2. The simplest way to categorize soil horizons is to recognize A, B, and C horizons corresponding respectively to topsoil, subsoil, and parent material.

3. Minerals are transported downward as a result of leaching, the process whereby minerals suspended or dissolved in liquid are transported to another location.

4. A crucial horizon for agriculture and ecosystems is the A horizon, or topsoil.

E. Soils differ in quality.

1. Scientists classify soils—and farmers judge their quality for farming—based on properties such as color, texture, structure, and pH. a. A soil’s color can indicate its composition and its fertility. b. Soil texture is determined by the size of particles. i. Clay particles are less than 0.002 mm in diameter, silt particles 0.002–0.05 mm, and sand 0.05–2 mm. ii. Soil with an even mixture of the three particle sizes is known as loam.

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c. Soil structure is a measure of the “clumpiness” of soil. d. Plants can die in soils that are too acidic or too alkaline, so soils of intermediate pH values are best for most plants.

F. Regional soil differences affect agriculture.

1. The traditional form of agriculture in tropical forested areas is swidden agriculture, in which the farmer cultivates a plot for one to a few years and then moves on to clear another plot, leaving the first to grow back to forest. Plots are often burned before planting, in which case the practice is called slash-and-burn agriculture.

IV.

Water for Agriculture A. Irrigation boosts productivity.

1. The artificial provision of water beyond what crops receive from rainfall is known as irrigation.

B. Salinization and waterlogging pose challenges.

1. Waterlogging occurs when overirrigation saturates the soil and causes the water table to rise to the point that water drowns plant roots, depriving them of access to gases and essentially suffocating them.

2. A more frequent problem is salinization, the buildup of salts in surface soil layers.

C. Sustainable approaches to irrigation maximize efficiency.

V.

Nutrients for Plants 1. Farmers enhance nutrient-limited soils by adding fertilizers, substances that contain essential nutrients.

A. Fertilizers boost crop yields but can be overapplied.

1. There are two main types of fertilizers. a. Inorganic fertilizers are mined or synthetically manufactured mineral supplements. b. Organic fertilizers consist of the remains or wastes of organisms and include animal manure, crop residues, fresh vegetation (green manure), and compost, a mixture produced when decomposers break down organic matter such as food and crop waste in a controlled environment.

B. Sustainable fertilizer use involves targeting and monitoring nutrients.

1. Precision agriculture involves using technology to precisely monitor crop conditions, crop needs, and resource use to maximize production while minimizing the waste of resources.

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VI.

Pollination for Farming 1. Pollination is the process by which male sex cells of a plant (pollen) fertilize female sex cells of a plant (ova, or egg cells).

Pollination can occur in different ways.

A. Many crops rely on pollinators.

B. Protecting pollinators protects agriculture.

C. Bee declines make pollinator conservation urgent.

1. Scientific data indicate that populations of honeybees and of wild native bees are declining steeply across North America. As bees disappear, we lose their services and risk lowered crop yields.

2. Scientists studying the pressures on bees, butterflies, and other pollinators are concluding that they are suffering a “perfect storm” of stresses—many of which result from industrial agriculture.

3. Researchers are finding that these multiple sources of stress seem to interact and cause more damage than the sum of their parts. Any or all of these factors may possibly play a role in what is being called colony collapse disorder, a mysterious malady that for the past decade has destroyed up to one-third of all honeybees in the United States each year.

D. We can help pollinators in many ways.

VII.

Preserving Genetic Diversity A. Industrial agriculture has diminished diversity.

1. Industrial farming has narrowed the human diet. 90% of the food we consume now comes from just 15 crop species and 8 livestock species.

B. Crop diversity provides insurance.

C. Seed banks are living museums.

1. Another way to preserve genetic assets for agriculture is to collect and store seeds from diverse crop varieties. This is the work of seed banks, institutions that preserve seed types as a kind of living museum of genetic diversity.

VIII. Conserving Soil and Land Resources A. Damage to soil and land makes conservation vital.

1. Land degradation refers to a general deterioration of land that diminishes its productivity and biodiversity, impairs the functioning of its ecosystems, and reduces the services that these ecosystems provide to us.

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2. Within the broad problem of land degradation, agricultural concerns often focus on what is known as soil degradation, the process by which soils deteriorate in quality and decline in productivity.

B. Erosion threatens ecosystems and agriculture.

1. Erosion is the removal of material from one place and its transport to another by the action of wind or water. Deposition occurs when eroded material is deposited at a new location.

2. People have made land more vulnerable to erosion in three ways: a. Overcultivating fields through poor planning or excessive tilling. b. Grazing rangeland with more livestock than the land can support. c. Clearing forests on steep slopes or with large clear-cuts.

3. To minimize erosion, we can erect physical barriers that capture soil.

C. Desertification reduces the productivity of arid lands.

1. Desertification is a loss of more than 10% productivity due to soil erosion, soil compaction, forest removal, overgrazing, drought, salinization, climate change, water depletion, and other factors.

2. Desertification is expected to grow worse as climate change alters rainfall patterns, making some areas drier.

D. The Dust Bowl prompted soil conservation in the United States.

1. In the early 1930s, a drought worsened the ongoing human impacts, and the region’s strong winds began to erode millions of tons of topsoil. The most affected region in the southern Great Plains became known as the Dust Bowl, a term now also used for the historical event itself.

2. In response, the U.S. government, along with state and local governments, increased support for research into soil conservation.

The U.S. Congress passed the Soil Conservation Act of 1935, which established the Soil Conservation Service (SCS).

3. In 1994, the SCS was renamed the Natural Resources Conservation Service (NRCS), and its responsibilities were expanded to include water quality protection and pollution control.

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E. Farmers conserve soil and resources in many ways.

1. Crop rotation describes the process in which farmers alternate the type of crop grown in a given field from one season or year to the next.

2. Contour farming is a process in which furrows are plowed sideways across a hillside, perpendicular to its slope and following the natural contours of the land.

3. Terracing transforms slopes into series of steps like a staircase, enabling farmers to cultivate hilly land without losing huge amounts of soil to water erosion.

4. The planting of different types of crops in alternating bands or other spatially mixed arrangements is called intercropping.

5. Shelterbelts are rows of trees or other tall shrubs that are planted along the edges of fields to slow the wind.

6. Conservation tillage encompasses an array of approaches that reduce the amount of tilling relative to conventional farming. Notill farming—the ultimate form of conservation tillage—eliminates tilling altogether. Rather than plowing after each harvest, farmers practicing conservation tillage leave crop residues atop their fields, keeping the soil covered with plant material.

F. Grazing practices affect soil and land.

1. When too many livestock destroy too much of the plant cover, impeding plant regrowth and preventing the regeneration of biomass, the result is overgrazing.

G. Subsidies and conservation measures influence ranching.

H. Policy can promote conservation measures in agriculture.

1. The Conservation Reserve Program, first established in the 1985 Farm Bill, pays farmers to stop cultivating damaged and highly erodible cropland and instead to place it in conservation reserves planted with grasses and trees.

2. Internationally, the United Nations promotes soil conservation and sustainable agriculture through a variety of programs led by the Food and Agriculture Organization (FAO).

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Key Terms agriculture bedrock clay compost Conservation Reserve Program conservation tillage contour farming crop rotation cropland deposition desertification Dust Bowl erosion fertilizer humus industrial agriculture inorganic fertilizers intercropping irrigation land degradation leaching loam monocultures no till

organic fertilizers overgrazing parent material pollination polycultures precision agriculture rangeland salinization sand shelterbelts silt slash and burn soil soil degradation soil horizon soil profile sustainable agriculture terracing topsoil traditional agriculture waterlogging weathering

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Teaching Tips 1. Bring soil samples to class so students can conduct a soil texture “feel test.” In general, sandy soils feel gritty, silty soils feel like flour, and clay soils are sticky when moistened. Soils feel different because of the size of the most abundant particle type. The USDA categorizes particles as follows: Sand: 0.05–2.0 mm in diameter Silt: 0.002–0.05 mm in diameter Clay: less than 0.002 mm in diameter For students to better understand the differences in soil particle size, have them visualize a barrel to represent a sand particle, a plate to represent a silt particle, and a dime to represent a clay particle.

Because most soils are a combination of sand, silt, and clay, soil scientists use a more complicated method to determine the percent composition of each type.

These percentage values are used in the USDA textural triangle (Figure 9.5) to determine the textural class of a soil.

A good addition to this exercise would be to give each group of students 100 g of soil from a different location. Have them run the soil through a set of soil sieves and then weigh the fractions to determine the percent composition of the different particle types (four or five types, depending on the soil sieves, ranging from gravel to clay). Have students make a pie chart or a bar graph illustrating the composition of their soil. Ask them to compare their results with those of other groups that have soils from other areas.

2. Soil formation is a very slow process, and in some cases it can take 500 years for one inch of soil to develop. To emphasize the importance of soil conservation, use the timeline below to show just how much can happen in 500 years—the time required to form an inch of soil.

2002: West Nile virus infects humans in the United States.

1996: The first animal, Dolly the sheep, is cloned from an adult cell.

1989: The Berlin Wall is torn down.

1970: The first Earth Day is celebrated.

1962: The Beatles, a British pop group, make their first recordings.

1945: World War II ends.

1934: The Dust Bowl occurs in the Great Plains.

1915: Albert Einstein formulates his general theory of relativity.

1872: Congress establishes the first national park, Yellowstone.

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1854: Henry David Thoreau publishes Walden.

1804: Lewis and Clark begin their expedition to the Northwest.

1788: The U.S. Constitution is ratified.

1681: The dodo, a large flightless bird, becomes extinct.

1608: Native Americans teach colonists how to raise corn.

1513: Juan Ponce de León discovers Florida.

1500: The Incan empire reaches its height.

3. Demonstrate runoff and erosion. First, put a piece of grass sod on a cafeteria tray. Have a student pour water over the sod using a watering can or a spray bottle to simulate rain. Observe the runoff. Repeat this procedure using a pile of loose dirt on a second tray. Compare the runoff. Repeat the procedure with each tray held at a 20- to 30-degree angle to simulate the problems on slopes.

4. Assign students to read the first chapter of The Grapes of Wrath by John Steinbeck. This chapter of the classic novel describes the conditions in Oklahoma right after the Dust Bowl that ruined crops, causing massive foreclosures on farmland.

5. Contemporary agriculture occupies a large area of the Midwest that was formerly tall grass prairie. Innovations in agriculture are reexamining the capacity of this landscape to produce biomass efficiently. Some cattle producers are removing cattle from large feedlots and returning them to permanent pastures composed of local native prairie grasses and wildflowers.

Native prairie vegetation has tremendous potential to store carbon in its root system. When compared to nonnative, cool-season European grasses commonly planted for hay and pastures, prairie species are able to absorb and hold much more rainwater and, because of the root system, more carbon.

To prove this to students, secure seeds of common, cool-season lawn grass such as perennial rye and native prairie species such as Big Bluestem, Little Bluestem, and Side Oats Grama. Have students plant several seeds in clay or peat pots, place them on a windowsill, and watch the events unfold. When several inches of growth have accumulated, gently pull the plants near the base and observe the root system. Depending on the time of year, the prairie grasses will exhibit robust root growth and might even be pot-bound. Prairies produce two-thirds of their biomass underground, making them excellent carbon sinks.

Sources for native prairie seed: Ion Exchange. 1878 Old Mission Drive, Harper’s Ferry, Iowa. 800-291-2143 (www.ionxchange.com).

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6. Use “signaling” for concept understanding. There are several sets of concepts in this chapter—soil horizons, types of erosion, and erosion reduction methods, for instance. A good way to check for understanding is signaling, originally designed by Dr. Madeline Hunter of UCLA. With the types of erosion, for instance, give students the following keys: Wind erosion: Hold out one hand with fingers extended, palm perpendicular to the desk. The fingers look like a flag blowing in the wind.

Splash erosion: Hold out one hand with palm parallel to and facing the desk, fingers spread wide apart and angling down toward the desk.

Sheet erosion: Hold out one hand with palm parallel to and facing the desk, fingers straight out and close together.

Rill erosion: Make a small fist.

Gully erosion: Hold out one hand with palm facing up as if cupping a softball or making the shape of a gully.

Now show students a photo or ask them to decide on the type of erosion that would occur in a particular circumstance. Students, on your mark, will indicate the answer with his or her signal. You can instantly tell which students know the correct answer, which are uncertain (hesitating, glancing around at others), and which have incorrect answers. This is an easy way to know if you need to cover a concept more thoroughly or if students are ready to move on.

Additional Resources Websites 1. Best Management Practices for Soil Erosion, U.S. Environmental Protection Agency (www.epa.gov/agriculture/agricultural-crops#erosion) A downloadable file at this website provides information about soil erosion worldwide, in the United States and in the Midwest in particular.

2. SOILS, Natural Resources Conservation Service (www.nrcs.usda.gov/wps/portal/nrcs/site/soils/home) Part of the National Cooperative Soil Survey, this website is an effort by federal and state agencies to provide scientifically based soil information.

3. The Leopold Center for Sustainable Agriculture, Iowa State University (www.leopold.iastate.edu) The Leopold Center funds innovative research on sustainable agriculture, water quality, fiber production, marketing, and policy initiatives. Their research papers and resources are available online.

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Audiovisual Materials 1. Ken Burns: The Dust Bowl, 2012, PBS home video distributed by WGBH (www.pbs.org/kenburns/dustbowl/) This program looks at America’s “worst ecological disaster,” which brought financial and emotional ruin to thousands of people in the Great Plains.

2. DIRT! The Movie, 2009, video distributed by Bullfrog Films (www.bullfrogfilms.com) The story of Earth’s most valuable and underappreciated source of fertility, from its miraculous beginning to its crippling degradation.

3. My Father’s Garden, 1995, Miranda Productions, video distributed by Bullfrog Films (www.bullfrogfilms.com) This documentary examines the use and misuse of technology on American farms. Compares industrial and organic farms.

4. New Deal for the Dust Bowl, 1991, distributed by Films for the Humanities and Sciences (www.films.com) Investigates the causes and effects of the Dust Bowl as well as the government’s intervention to prevent another one from occurring.

5. Food Forward, 2014–2015, distributed by PBS (www.pbs.org/show/foodforward/) This 13-episode series explores food-related issues including food waste, water use, eating meat, and soil erosion.

Weighing the Issues How Would You Farm?

Facts to consider: There are two related concerns: water conservation and soil conservation. Water conservation is important because a poorly designed field on this hill will have high runoff, removing soil through erosion. Irrigation techniques will need to prevent excessive runoff. Soil conservation has a second component—the quality of the soil. This includes nutrients, soil fauna diversity, and the abiotic structure of the soil (the percentage of sand, clay, and the like).

Crop rotation is one strategy. The quantity of the soil must also be maintained through contour farming, terracing, or methods to prevent wind from removing soil. An additional factor is cost. For example, if no- or reduced-tillage farming is used, the farmer may have extra herbicide or labor costs because unwanted seeds can become buried alongside planted seeds. Other costs might be the work of contouring or terracing and the careful construction of irrigation.

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Soils, Subsidies, and Sustainability Facts to consider: Lands under the Conservation Reserve Program now cover an area nearly the size of Virginia, and the U.S. Department of Agriculture (USDA) estimates that each dollar invested in this program saves nearly one ton of topsoil.

Congress reauthorized and expanded the Conservation Reserve Program in the farm bills of 1996, 2002, 2008, and 2014. The 2014 bill funded 15 other similar programs (including the Wetlands Reserve Program) for the conservation of soil, grasslands, wetlands, and wildlife habitat.

Have students reflect on the economics chapter as well as the definition of sustainability. Have them revisit the concept of assessing monetary value to the benefit received by preserving and conserving land. Have students map the pros and the cons of what the Conservation Reserve Program has accomplished with taxpayer money. Then address how this would change, for both the good and the bad, without government regulation.

The Science behind the Story If We Help Pollinators, Will It Boost Crop Production?

Question: Do farmers who invest in assisting bees and other pollinators see that investment paid back by increased crop yields?

Studies: Numerous studies have been carried out to learn whether investing in pollinators pays off financially for farmers. To begin, researchers compared visitation and pollination by native bees and honeybees on organic and conventional fields, near and far from native habitat. More recently, researchers have manipulated agricultural fields, creating new habitat for pollinators. In these studies, small plots or buffer strips of wildflowers, native shrubs, or grasses were established in or near agricultural fields. Pollination and fruit production were recorded in the treated fields and similar control fields that did not receive flowering treatments.

Results: Most of these studies found that pollination and crop yields were higher for areas near native habitat or constructed pollinator-friendly habitat. Thus, it appears that investing in pollinators can result in increased profits.

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Local Connections What are the major agricultural products grown or processed in your state or region? Which of them rely on pollinators? What type(s) of pollinators do these agricultural products depend on? Describe three steps that are being taken, or that could be taken, to help conserve these pollinators in your state or region.

Class time required: one class period or could be completed as a homework assignment Students could work on this activity individually or in small groups. Depending on the area, students may find many products or just a few. If you are in an area with a large agricultural sector, you may need to limit the number or crops to five or ten. After students have completed their work, have students or groups share their ideas for pollinator conservation with the class to initiate a class discussion on the topic.

Calculating Ecological Footprints Plant products consumed (lb)

Soil loss (lb) at 5:1 ratio

Soil loss (lb) at 3:1 ratio

Soil loss prevented (lb) at 3:1 relative to 5:1 ratio

365

1,825

1,095

730

Your class

Answers will vary

Answers will vary

Answers will vary

Answers will vary

Your state

Answers will vary

Answers will vary

Answers will vary

Answers will vary

United States

1.182  1011

5.913  1011

3.548 1011

2.365  1011

You

1. Answers in table. Answers will vary.

2. Answers in table. Answers will vary.

3. A sustainable rate of soil loss is one that does not exceed the local rate of soil formation. Measuring the amount of topsoil at a farm over time will reveal whether farm practices are sustainable.

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10 Making Agriculture Sustainable Chapter Objectives This chapter will help students: Explain the challenge of feeding a growing human population Identify the goals, methods, and consequences of the Green Revolution Discuss how we raise animals for food, and assess the impacts of meat consumption Explore strategies for pest and weed management

Describe the science behind genetic engineering Compare the benefits and costs of genetically modified foods, and assess the public debate over them Analyze the nature, growth, and potential of organic agriculture Summarize potential pathways toward sustainable agriculture

Lecture Outline I.

Sustainable Food and Dining at the University of Michigan A. The University of Michigan is a leader in sustainable dining.

B. In 2011, students won a $42,000 grant from the university’s sustainability program to establish a campus farm.

C. In 2017, the Campus Farm was certified by the U.S. Department of Agriculture to sell its produce and MDining began buying it.

D. MDining minimizes food waste through various programs.

1. MDining uses trayless dining and smaller portion sizes to minimize food waste.

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2. Dining halls offer vegetarian and vegan selections.

3. Sustainably sourced seafood is encouraged over red meat.

4. Food scraps are composted and used cooking oil is recycled into biodiesel.

E. Schools across the country are pursuing culinary sustainability.

II.

The Race to Feed the World A. We are producing more food per person.

1. Over the past half-century, our ability to produce food has grown faster than our global population.

2. However, ensuring that our food production can be sustained depends on conserving soil, water, and biodiversity by using careful agricultural practices.

B. We face nutritional challenges.

1. People suffer from undernutrition, receiving fewer calories than the minimum dietary energy requirement.

2. Agricultural scientists and policymakers worldwide pursue a goal of food security, the guarantee of an adequate, safe, nutritious, and reliable food supply available to all people at all times.

3. Those who suffer from overnutrition receive too many calories each day.

4. Just as the quantity of food a person eats is important for health, so is the quality of food. Malnutrition, a shortage of nutrients the body needs, occurs when a person fails to obtain a complete complement of essential proteins, lipids, vitamins, or minerals.

C. Agriculture has changed over time.

1. During most of human existence, we were hunter-gatherers.

2. About 10,000 years ago, people began to plant seeds and to domesticate animals.

3. During these past few thousand years, most people practiced traditional agriculture. Recently, the industrialization of agriculture has boosted yields.

D. The Green Revolution boosted yields worldwide.

1. Realizing that farmers could not go on forever converting additional land to increase production, agricultural scientists devised methods and technologies to increase crop yields on existing cultivated land, called the Green Revolution.

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2. The transfer of technology and practices to the developing world that marked the Green Revolution began in the 1940s, when American agricultural scientist Norman Borlaug introduced Mexico’s farmers to a specially bred type of wheat.

3. Soon, many developing countries were doubling, tripling, or quadrupling their yields using selectively bred strains of wheat, rice, corn, and other crops from industrialized nations.

E. Industrialized agriculture has brought mixed consequences.

1. Developing countries imported the methods of industrialized agriculture and began applying large amounts of synthetic fertilizers and chemical pesticides on their fields, irrigating crops generously with water, and using more machinery powered by fossil fuels.

2. This high-input agriculture succeeded in producing more corn, wheat, rice, and soybeans from each hectare of land.

3. Between 1961 and 2013, global food production more than tripled and per-person food production rose 48% while area converted for agriculture increased only 11%. On the negative side, the intensified use of fossil fuels, water, inorganic fertilizers, and synthetic pesticides has worsened pollution, topsoil erosion, and soil and water quality.

4. The planting of monocultures, large expanses of single crop types, has made planting and harvesting more efficient, but has reduced biodiversity and increased the susceptibility of entire crops to disease, pathogens, and insect pests. This brings the risk of catastrophic failure.

F. How can we achieve sustainable agriculture?

1. Sustainable agriculture consists of farming and grazing that maintain healthy soil, clean water, pollinators, genetic diversity, and other resources needed for the production of crops and livestock over the long term.

III.

Raising Animals for Food A. Consumption of animal products is growing.

1. Global meat production has increased more than five-fold since 1950, and per capita meat consumption has doubled.

B. Our food choices have environmental consequences.

1. Eating meat is far less energy-efficient than relying on a vegetarian diet, and it leaves a far greater ecological footprint.

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2. In contrast, if we eat lower on the food chain (a more vegetarian diet, with fewer animal products), we put a greater proportion of the sun’s energy to use as food for ourselves.

3. Some animals convert grain feed into milk, eggs, or meat more efficiently than others.

4. The FAO reports that across the world, livestock agriculture contributes 5% of our carbon dioxide emissions, 44% of our methane emissions, and 53% of our nitrous oxide emissions, accounting altogether for 14.5% of the emissions driving climate change—a larger share than automobile transportation.

C. Feedlots have benefits and costs.

1. Feedlots, also known as factory farms or concentrated animal feeding operations, are huge pens designed to deliver energy-rich food to animals living at high densities.

2. Feedlots allow for economic efficiency and greater food production, and this makes animal products affordable to more people.

3. For environmental quality, feedlots offer one very significant benefit: Taking cattle and other livestock off pastureland and concentrating them in feedlots reduces grazing impacts across large areas of the landscape.

4. At the same time, intensified animal production at feedlots can result in intensive pollution. Livestock produce prodigious amounts of manure and urine, and the highly concentrated waste from feedlots can pollute surface water and groundwater.

5. The crowded conditions under which animals are kept in feedlots necessitate heavy use of antibiotics to control disease.

6. The Environmental Protection Agency and state agencies keep a watchful eye on U.S. feedlots, regulating them to minimize environmental impacts.

D. Is lab-grown meat a solution?

1. Using techniques of in vitro tissue culture, animal muscle cells can be cultivated in the lab to form lab-grown meat, also called cultured meat.

E. We raise seafood with aquaculture.

1. The cultivation of aquatic organisms for food in controlled environments is called aquaculture.

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2. Aquaculture is the fastest-growing type of food production; global output has increased eight-fold in just the past 30 years.

F. Aquaculture brings benefits and costs.

1. Aquaculture increases food supplies and helps ensure reliable protein sources, thus improving food security for humans.

Aquaculture reduces fishing pressures on overharvested and declining wild stocks.

2. When practiced on a small scale by families or villages, as in much of the developing world, community-based aquaculture can be sustainable, and its compatibility with other activities can make it an effective path toward sustainable agriculture.

3. At large scales, industrialized aquaculture produces ample amounts of food but also exerts environmental impacts. a. Dense concentrations of farmed animals can incubate disease, which necessitates antibiotic treatment, results in expense, and can reduce food security. b. If farmed aquatic organisms escape into ecosystems where they are not native, they may spread disease to native stocks or may outcompete native organisms for food or habitat.

IV.

Controlling Pests and Weeds A. “Pests” and “weeds” hinder agriculture.

1. A pest is any organism that damages crops or livestock. A weed is any plant that competes with our crops.

B. We have developed thousands of chemical pesticides.

1. Poisons that target pest organisms are called pesticides.

C. Pesticides boost food production but also have negative impacts.

1. Exposure to synthetic pesticides can have health consequences for people.

2. An additional problem is that pesticides commonly kill nontarget organisms, including the predators and parasites of the pests they are meant to target.

3. Today a new class of chemical insecticide has become common: neonicotinoids. Seed companies treat crop seed with neonicotinoids, and they become systemic in the plant, dispersing throughout its tissues as it grows, and ending up in leaves, stems, flowers, fruit, and pollen.

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D. Pests evolve resistance to pesticides.

1. Industrial chemists are caught up in an evolutionary arms race with the pests they battle, racing to increase or retarget the toxicity of their chemicals while the armies of pests evolve ever-stronger resistance to their efforts.

E. Biological control pits one organism against another.

1. Biological control, or biocontrol, operates on the principle that “the enemy of one’s enemy is one’s friend.” We find natural enemies, or predators, of a species we consider a pest and introduce them to an area where the pests are a problem.

2. A widespread modern biocontrol effort has been the use of Bacillus thuringiensis (Bt), a naturally occurring soil bacterium that produces a protein that kills many caterpillars and some fly and beetle larvae.

F. Biocontrol agents themselves can become pests.

1. Because of concerns about unintended impacts, researchers study biocontrol proposals carefully before putting them into action, and government regulators must approve these efforts.

G. Integrated pest management combines biocontrol and chemical methods.

1. Integrated pest management (IPM) incorporates numerous techniques, including biocontrol, use of chemicals when needed, close monitoring of populations, habitat alteration, crop rotation, transgenic crops, alternative tillage methods, and mechanical pest removal.

V.

Genetically Modified Food 1. Genetic engineering refers to any process whereby scientists directly manipulate an organism’s genetic material in the laboratory by adding, deleting, or changing segments of DNA. Genetic engineering is one form of biotechnology, the material application of biological science to create products derived from organisms.

A. We have many ways of modifying foods.

1. People have been using traditional selective breeding for millennia to improve crops and livestock. In this approach, we breed individuals

together to produce more of the traits we desiree to see.

2. Using chemicals or radiation, scientists have encouraged the emergence of heritable mutations. Mutagenesis or mutation breeding of the last 100 years has resulted in many of the current varieties of crops we eat today.

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3. Genetically modified foods are foods derived from GMOs,

organisms that are genetically engineered.

An organism that contains DNA from another species is called a transgenic organism, and a gene transferred between them is called a transgene.

4. Using an array of new techniques for gene editing, or genome editing, scientists can now insert, delete, or change short stretches of DNA to turn particular genes on or off, or to modify their effects. a. One popular such approach, called CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats), uses genetic material from bacteria that the bacteria had used to fight infection from viruses.

B. Biotechnology is transforming the products around us.

C. What are the benefits of GM crops?

1. Proponents of genetic engineering maintain that GM foods bring substantial environmental and social benefits and assist the pursuit of sustainable agriculture in several major ways. a. By increasing production of food and fiber while lowering costs, GM crops enhance food security and reduce poverty and hunger for millions of people. b. By raising yields on existing farmland, GM crops alleviate pressure to clear forests and convert natural lands for agriculture, thus helping to conserve biodiversity, habitat, and ecosystem services. c. Crops engineered for drought tolerance help conserve water by reducing the need for irrigation. d. Crops engineered for better nutrition could help fight malnutrition and enhance children’s health in developing nations. e. GM crops that reduce fossil fuel use during cultivation help to lower greenhouse gas emissions and address climate change. f. Crops engineered for insect resistance allow farmers to eliminate or reduce the use of chemical insecticides.

2. In 2014, researchers conducted a meta-analysis, an effort that gathers results from all scientific studies on a particular research question and statistically analyzes their data for significant patterns or trends. This meta-analysis calculated that on average, researchers 156 ..

to that point had found that the adoption of GM crops increased yields by 22% and boosted farmers’ profits by 68% while reducing chemical pesticide use by 37%.

3. To understand the effects on pesticide use, however, we need to consider insecticides and herbicides separately.

D. What are the risks of GM foods?

1. Many people worry about health impacts from eating GM foods, but this widespread public anxiety has not been corroborated by research.

2. Most scientists who harbor concerns over GMOs focus on potential ecological impacts.

3. Many experts feel we should proceed with caution, adopting the precautionary principle, the idea that one should not undertake a new action until the ramifications of that action are well understood.

E. Public debate over GMOs continues.

1. More than 60 nations require foods with genetically engineered ingredients to be labeled so that consumers know what they are buying.

2. Proponents of labeling argue that consumers have a right to know what’s in the food they buy.

3. The perceived lack of control over one’s own food has driven concern that the global food supply is being dominated by a handful of large corporations that develop GM technologies.

4. Corporations patent the transgenes they develop and go to great lengths to protect their investments.

5. Today, there is widespread concern that the burgeoning organic food market will be hindered if organic farms experience an influx of pollen or seed from GM plants.

VI.

Organic Agriculture 1.

Food-growing practices that do not use synthetic fertilizers, pesticides, hormones, or antibiotics—but instead rely on biological approaches such as composting and biocontrol—are termed organic agriculture.

A. Organic approaches reduce inputs and pollution.

1. For farmers, organic farming can bring many benefits: lower input costs, enhanced income from higher-value produce, and reduced chemical pollution and soil degradation.

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2. Many consumers favor organic food out of concern about health risks posed by the pesticides, hormones, and antibiotics used in conventional industrial agriculture. Consumers also buy organic products out of a desire to improve environmental quality. The main obstacle for consumers is price.

B. Organic agriculture is on the rise.

1. Government initiatives are assisting the growth of organic farming.

C. Can organic agriculture feed the world?

VII.

Sustainable Food Production A. We can consider multiple paths toward sustainable agriculture.

B. Locally supported agriculture has grown.

1. At farmers’ markets, consumers buy meats and fresh fruits and vegetables in season from local producers.

2. Some consumers are partnering with local farmers in communitysupported agriculture (CSA). In a CSA program, consumers pay farmers in advance for a share of their yield, usually a weekly delivery of produce.

3. Farmers’ markets and community-supported agriculture help strengthen local economies while giving the consumer access to fresher foods.

4. To determine which alternative involves less energy use overall, one needs to conduct a life-cycle analysis—a quantitative analysis of the inputs and outputs across all stages of an item’s production, transport, sale, and use.

C. Hydroponics conserves key resources.

1. Hydroponics is the practice of growing plants without soil.

D. Sustainable agriculture mimics natural ecosystems.

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Key Terms aquaculture Bacillus thuringiensis (Bt) biological control biotechnology colony collapse disorder community-supported agriculture (CSA) farmers’ markets feedlots food security genetic engineering genetically modified food genetically modified organism (GMO) Green Revolution integrated pest management (IPM)

life cycle analysis malnutrition meta-analysis neonicotinoids organic agriculture overnutrition pest pesticides precautionary principle seed banks sustainable agriculture transgene transgenic undernutrition weed

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Teaching Tips 1. This chapter describes the use of pesticides in agriculture. By their nature, pesticides may pose harm to humans, pets, and the environment because they are designed to adversely affect and/or kill certain organisms.

What some people do not realize is that many household products act as pesticides. It is extremely important to read the labels of those products for their safe use and disposal. The Consumer Labeling Initiative (CLI) and its “Read the Label First” program (archive.epa.gov/pesticides/regulating/conlabels/web/html/consumer-labeling.html) are efforts by the EPA to “foster pollution prevention, empower consumer choice, and improve consumer understanding of safe use, environmental, and health information on household consumer product labels.”

To introduce students to pesticide labels, bring some pesticide products from home such as bug sprays, flea collars, and disinfectants. Have students bring in such products from their homes too. Ask students to identify the warnings on the labels that the EPA requires.

2. Many people are concerned with the levels of pesticides and other agricultural chemicals in foods. The Food and Drug Administration conducts a Total Diet Study (also called the Market Basket Study) in several locations across the country. Its purpose is to determine the levels of various contaminants and nutrients in foods. Sample collections are carried out four times a year in each of four geographic regions of the country. FDA personnel buy about 280 foods from supermarkets, grocery stores, and fast-food restaurants in three cities in the region. The regional samples are shipped to a central FDA laboratory, prepared table-ready, combined to form a single analytical composite for each TDS food, and analyzed for pesticide residues, industrial chemicals, radionuclides, toxic and nutrient elements, and folate.

Students can determine the levels of contaminants in the foods they eat by going to the FDA pesticides website at www.fda.gov/Food/FoodScienceResearch/TotalDietStudy/default.htm.

About two-thirds of the way down the page are links to the Total Diet Study, which analyzes the amount of pesticides in the average diet, based on age and sex. Download the TDS diet and import the data files into database software such as Excel, which will allow you to sort it, perform searches, or prepare reports as desired.

3. Reading, interpreting, and creating graphs and charts are difficult tasks for many students. Consider having an introductory activity that explains the difference between continuous and discrete data, and the most useful graphing methods for each. Continuous data consist of a large number of values with no category label for the values. Are there more values possible between the listed 160 ..

values? If so, your data are probably continuous. In a study of tree health in a forest, there are many continuous variables, such as the height of each tree, the age of the tree as determined by coring, the number of main branches, etc.

Continuous data are usually best shown on a line graph because this can show that it is possible to understand information between the data points along the line.

Discrete or categorical data consist of only a small number of values, each corresponding to a specific category value or label. Tell students to ask themselves whether they can state all the possible categories or values of the data quickly. If they can, the data are probably discrete. In a study of tree health in a forest, there are many discrete variables, such as tree species, whether the tree is alive, whether there is significant insect damage, etc.

Discrete data are usually best shown with a bar graph because this can show that these are distinct categories. For example, there can be pine and oak trees, but you can’t have a tree that’s a pine-oak. A line graph makes no sense for this type of data.

If you are illustrating the parts of a whole (for example, percentages of people choosing from a range of alternatives such as preferred automobile types and related mpg figures), then use a pie chart indicating the proportion of the whole that each group uses.

4. Have students keep a log of what they ate in a 24-hour period, noting the country of origin for each food. Using a world map large enough for all students in the classroom to view, plot what local food security advocates call the “food miles” for the foods that the students ate. Consider a nominal reward for the person who had the meal that was most “local” in terms of what foods the region provides. (While not a food group, caffeine from coffee or tea counts in this activity.)

Additional Resources Websites 1. Agriculture 21 Magazine, Food and Agricultural Organization of the United Nations (www.fao.org/ag/portal/index_en/en) This e-magazine has articles about agricultural topics from around the world such as biotechnology, new animal diseases, and conservation agriculture.

2. National Agricultural Library, Agricultural Research Service, U.S. Department of Agriculture (www.nal.usda.gov)

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This online library is a major international source for agriculture and related information.

3. Animal Feeding Operations, National Pollution Discharge Elimination System, U.S. Environmental Protection Agency (www.epa.gov/npdes) This website is an overview of animal feeding operations and the regulation of animal waste.

4. Feeding the World Through Responsible Aquaculture, Global Aquaculture Alliance (www.gaalliance.org) The Global Aquaculture Alliance is an international association dedicated to promoting best management practices for sustainable aquaculture.

5. About Pesticides, U.S. Environmental Protection Agency (www.epa.gov/pesticides) This EPA website introduces pesticides and how they are regulated.

Audiovisual Materials 1. Sowing Seeds of Hunger, 2002, produced by Television Trust for the Environment and distributed by Bullfrog Films (http://www.bullfrogfilms.com) This program examines how the AIDS epidemic in sub-Saharan Africa has crippled the agricultural community while forcing children to undertake the responsibilities of farming.

2. My Father’s Garden, 1995, produced by Miranda Productions and distributed

by Bullfrog Films (www.bullfrogfilms.com) This documentary examines the use and misuse of technology on American farms, both industrial and organic.

3. Corporate Agriculture: Cultivating Trouble, 2004, distributed by Films for the Humanities and Sciences (www.films.com) This program examines the growth of corporate factory agriculture, an industry that can have environmental, social, and cultural repercussions.

4. Alternative Agriculture: Food for Life, 2004, distributed by Films for the Humanities and Sciences (www.films.com) Examines ecological, organic, and ethical farming as a viable alternative to industrial agriculture, and how this type of farming offers a tremendous benefit to the environment while helping to preserve traditional rural life.

5. NOW with Bill Moyers: Seeds of Conflict, 2002, distributed by PBS (www.pbs.org/now/science/genedebate.html)

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This episode examines the debate over the introduction of genetically modified food items into the human diet, their impact on local and global ecology, and the cultural impact surrounding systems of indigenous knowledge.

6. Food Forward, 2014–2015, distributed by PBS (www.pbs.org/show/food-forward/) This 13-episode series explores food-related issues including food waste, water use, eating meat, and soil erosion.

Weighing the Issues Feedlots and Animal Rights Facts to consider: Answers will vary. One approach to these questions is to consider the effect of the rising demand for meat. Agribusiness is responding by raising animals in as efficient a way as possible to respond to demand and maximize profits. Feedlots can be ecologically beneficial by removing large herds of grazing animals from grasslands and preventing the consequences that come with overgrazing. In terms of environmental safety, however, feedlots are a disaster. They introduce large amounts of fecal matter and growth hormones into surface and ground waters. Rising dust from livestock pens also releases fecal matter and strong odors into the air. Finally, when resource use is considered, livestock consume what humans could be consuming if the huge demand for meat were absent. Some people choose to become vegetarians for these reasons.

Reducing meat demand would free up much of the land needed to feed the increasing human population and would decrease the need for feedlots, with their negative environmental impacts.

Meat Grown in a Lab? Facts to consider: Lab-grown meat is a new development in the food industry.

People are often wary of new products, especially ones that they will put inside their bodies. Over time, the stigma can be reduced through clever marketing. In particular, companies can advertise it as a more sustainable alternative to traditional meat. At this time, barriers to mass consumption include price and availability. People will almost certainly be less likely to try the new product if it is considerably more expensive than traditionally-raised meat.

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Do You Want Your Food Labeled?

Facts to consider: This question requires a personal response. All agriculture, and hence food choices, has good and bad environmental impacts. In the case of shadegrown coffee plantations, for example, how the coffee is grown has a positive effect on the ecosystem’s flora and fauna. Eating produce and meat grown without chemical fertilizers, pesticides, and growth hormones keeps these persistent chemicals out of flora and fauna. These farming methods are expensive, and farmers—many of whom just barely break even financially during the year— revert to tried-and-true farming methods that are not environmentally friendly.

Purchasing power has been an effective way for groups to make their views known about food preferences, some of which have, in fact, influenced food manufacturers. GM foods may be another area in which this proves to be the case.

The Science behind the Story What Are the Impacts of GM Crops?

Observation: Most of us are confronted with such a deluge of information—and misinformation—about genetic engineering and GM crops that it can be hard to know what to believe.

Question: What impacts do genetically modified crops have?

Hypothesis: Broad assessments of the scientific research on genetically modified foods will be most accurate in assessing impacts of GMOs. Study: Wilhelm Klümper and Matin Qaim of Georg-August-Universität Göttingen, Göttingen, Germany, found 24,000 potential studies in total and screened them for suitability until arriving at 147 that compared GM crops to nonGM ones and met all requirements of the meta-analysis. Klümper and Qaim then used variants on the statistical technique known as regression to test for patterns in types of impacts that the studies had documented.

Results: Analysis indicated that GM crops help farmers produce more food while applying fewer pesticides. Because farmers have so much more crop to sell, their profits rise by 68% with GM crops, according to the analysis. Pesticide savings were entirely due to reductions in insecticide use due to the planting of insectresistant crops such as Bt corn and cotton. Insect-resistant crops showed a 42% reduction in chemical application, whereas herbicide-tolerant crops such as Roundup Ready canola showed no significant difference in chemical application compared with non-GM crops. Yields were also substantially greater with insectresistant crops than with herbicide-tolerant ones.

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How Productive Is Organic Farming?

Observation: Organic farming puts fewer synthetic chemicals into the soil, air, and water than conventional industrial farming does.

Question: But can organic farming produce large enough crop yields to feed the human population?

Hypothesis: Organic farms are better able to sustain high soil quality that produces substantial amounts of food.

Study: At the research site, wheat, potatoes, and other crops are grown in plots cultivated in different treatments: conventional farming using chemical pesticides, herbicides, and inorganic fertilizers; conventional farming that also uses organic fertilizer (cattle manure); organic farming using only manure, mechanical weeding, and plant extracts to control pests; and organic farming that also adds natural boosts, such as herbal extracts in compost. Researchers record crop yields at harvest each year. They analyze the soil regularly, measuring nutrient content, pH, structure, and other variables. They also measure the biological diversity and activity of microbes and invertebrates in the soil. Such indicators of soil quality help researchers assess the potential for long-term productivity.

Results: Over the study’s 21 years, the organic fields yielded 80% of what the conventional fields produced. Organic potato crops averaged just 58% to 66% of conventional yields because of nutrient deficiency and disease, but organic crops of winter wheat produced 90% of conventional yields. Although the organic plots produced 20% less on average, they received 35% to 50% less fertilizer than the conventional fields and 97% fewer pesticides. Thus, Mäder’s team concluded, the organic plots were highly efficient and represent “a realistic alternative to conventional farming.” Mäder’s team found that soil in the organic plots had better structure, better supplies of some nutrients, and much more microbial activity and invertebrate biodiversity than soil in conventional fields supplemented with manure. Organic fields outperformed conventional fields without manure still more.

Local Connections What initiatives is your college or university pursuing along the lines of sustainable food and dining? Does your school have a farm on campus? If so, research what is grown there and what students do on the farm and then report on what you find. Does your dining hall source food from your campus farm? From local farmers? Does it take any steps to encourage healthy eating? Is it easy to find vegetarian or vegan meal options? What does your dining hall do to reduce food waste? Does it use trayless dining or compost its waste? Describe what steps your 165 ..

school’s dining services are taking toward sustainable dining. Is your school doing anything beyond what the University of Michigan is doing? If you wished to, how could you get involved in food or dining sustainability issues on campus?

Class time required: Variable. See below.

Because there are many aspects to this prompt, this activity could be structured to be completed in one class period by breaking the research into sections and assigning students to each section or it could be structured to take several class periods or be completed over several weeks as a homework assignment.

For some schools, the information necessary to answer this prompt may be available on the university website. However, some of the information will likely need to be collected through interviews or site visits. If your campus has a sustainability office, you may want to invite the director to your class to answer questions directly.

Calculating Ecological Footprints Food type

Total emissions across life cycle

Emissions from delivery

Percent emissions from delivery

Fruits and vegetables

0.85

0.10

11.8

Cereals and carbohydrates

0.90

0.07

7.78

Dairy products

1.45

0.03

2.07

Chicken/fish/eggs

0.75

0.03

4.00

Red meat

2.45

0.03

1.22

Beverages

0.50

0.04

8.00

1. Red meat is responsible for the most greenhouse gas emissions across its whole life cycle. Beverages are responsible for the fewest emissions.

2. The range of values for percent of emissions from transport of food to retailers is 1.22–11.8. Students might best reduce their own footprint with regard to food at the source, rather than in trying to slim the already small margin of emissions demanded in delivery.

3. Answers will vary.

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11 Biodiversity and Conservation Biology Chapter Objectives This chapter will help students: Characterize the scope of biodiversity on Earth Specify the benefits that biodiversity brings us Discuss today’s extinction crisis in a geological context Evaluate the primary causes of biodiversity loss Assess the science and practice of conservation biology Analyze efforts to conserve threatened and endangered species Compare and contrast conservation efforts above the species level

Lecture Outline I.

Central Case Study: Will We Slice Through the Serengeti?

A. The epic wildebeest, zebra, and antelope migration may be threatened by a proposal to build a commercial highway across the Serengeti, slicing straight across the animals’ migratory route.

B. Because the Maasai subsist on their cattle and have lived at low population densities, wildlife thrived here long after it had declined in other parts of Africa.

C. When East Africa was under colonial rule, the British created game reserves to conserve wildlife for their own hunting.

D. Today, 2 million people visit Tanzania and Kenya each year, most of them ecotourists who visit the parks and protected areas. As such, the parks have become mainstays of these national economies.

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E. East Africa has been at the forefront of community-based conservation, in which local people act as stewards, managing their own resources, often in collaboration with international conservationists.

F. Tanzania’s former president Jakaya Kikwete promised to build a paved commercial highway across the Serengeti.

G. Around the world, conservationists reacted with alarm.

1. Scientists predicted that the road and its vehicles would physically block migration routes and kill countless animals in collisions.

2. A highway would also provide access for poaching, the illegal killing of wildlife for meat or body parts.

3. Likewise, it would allow an entry corridor for exotic plant species that could invade the ecosystem.

4. A highway would encourage human settlement right up to the park boundary, making the park an island of habitat hemmed in by agriculture, housing, and commerce.

5. By boosting development, the towns on Lake Victoria would grow into large cities, creating demand for still-larger transportation corridors in the future.

H. Such an outcome could devastate tourism, so the region’s tourism operators opposed the highway. So did most Kenyans, who feared that the highway would prevent migratory animals from reaching Kenya’s Maasai Mara Reserve.

I. Meanwhile, international pressure rose on Tanzania to abandon its plans.

J. Then in 2016, shortly after John Magufuli took office as Tanzania’s president, a new plan kicked off debate. The nation of Uganda wanted to export oil from its recently developed oilfields eastward to ports on the Indian Ocean. Three routes for an oil pipeline were proposed, and the most direct option would cut straight across Serengeti National Park.

K. Faced with the opposition, Magufuli’s government announced that any pipeline route would avoid passing through game reserves and national parks.

II.

Life’s Diversity on Earth A. Biodiversity encompasses multiple levels.

1. Biological diversity, or biodiversity, is the variety of life across all levels of biological organization, including the diversity of species, genes, populations, communities, and ecosystems.

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2. Species diversity describes the number or variety of species found in a particular region. a. A species is a set of individual organisms that shares unique characteristics and can breed with one another and produce fertile offspring. b. Species form by the process of speciation and may disappear by extinction. c. Species richness describes the number of species. d. Another component of species diversity is evenness or relative abundance, the extent to which species differ in number of individuals. e. Biodiversity exists below the species level in the form of subspecies, populations of a species that occur in different geographic areas and differ from one another in slight ways.

3. Genetic diversity encompasses the differences in DNA composition among individuals. a. Genetic diversity provides the raw material for adaptation to local conditions. b. Populations with little genetic diversity are vulnerable to environmental change if they lack genetic variants to help them adapt to novel conditions.

4. Ecosystem diversity refers to the number and variety of ecosystems, but biologists may also refer to the diversity of communities or habitats.

B. Biodiversity is unevenly distributed.

1. Some groups of organisms include more species than others.

2. Species richness generally increases as one approaches the equator.

This pattern of variation with latitude is called the latitudinal gradient in species richness.

3. For any given region, species diversity tends to increase with diversity of habitat.

C. Many species await discovery.

1. So far, scientists have identified and described about 1.8 million species of plants, animals, and microorganisms.

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2. Our knowledge of species numbers is incomplete for several reasons. a. Many species are tiny and easily overlooked. b. Many organisms are difficult to identify; sometimes organisms thought to be of the same species turn out to be different species once examined more closely. c. Some areas of Earth remain little studied.

III.

Benefits of Biodiversity A. Biodiversity enhances food security.

B. Organisms provide drugs and medicines.

1. People working for pharmaceutical companies engage in bioprospecting, searching for organisms that might provide new drugs, medicines, foods, or other valuable products.

C. Biodiversity provides ecosystem services.

D. Biodiversity helps maintain functioning ecosystems.

E. Biodiversity boosts economies through tourism and recreation.

F. People value connections with nature.

1. Edward O. Wilson has popularized the notion of biophilia, asserting that human beings share an instinctive love for nature and feel an emotional bond with other living things.

G. Do we have ethical obligations toward other species?

IV.

Biodiversity Loss and Extinction A. Human disturbance creates winners and losers.

B. Many populations are declining.

C. Extinction is irreversible.

1. Extinction occurs when the last member of a species dies and the entire species ceases to exist. The disappearance of a particular population from a given area, but not the entire species globally, is called extirpation.

2. Most extinctions preceding the appearance of human beings occurred singularly for independent reasons, at a pace referred to as the background extinction rate.

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D. Earth has experienced five mass extinction events.

1. In the past 440 million years, our planet has experienced five major mass extinction events. Each event eliminated more than one-fifth of life’s families and at least half its species.

2. If current trends continue, our modern era, known as the Quaternary Period, may see the extinction of more than half of all species.

E. We are setting the sixth mass extinction in motion.

1. To monitor threatened and endangered species, the International Union for Conservation of Nature (IUCN) maintains the Red List, a continuously updated list of species facing high risks of extinction.

F. Several major causes of biodiversity loss stand out.

1. Habitat loss a. Habitat loss occurs most commonly through gradual, piecemeal degradation, such as habitat fragmentation.

2. Pollution 3. Overharvesting a. Poaching, the illegal killing of wildlife for meat or body parts, is one way that overharvesting or overexploitation can occur.

4. Invasive species 5. Climate change G. A mix of causes threatens many species.

V.

Conservation Biology: The Search for Solutions 1. Conservation biology is a scientific discipline devoted to understanding the factors, forces, and processes that influence the loss, protection, and restoration of biological diversity.

A. Conservation biology responds to biodiversity loss.

B. Endangered species are a focus of conservation efforts.

1. The primary legislation for protecting biodiversity in the United States is the Endangered Species Act (ESA). Enacted in 1973, the Endangered Species Act offers protection to species that are judged to be endangered (in danger of becoming extinct in the near future) or threatened (likely to become endangered soon). The ESA forbids the government and private citizens from taking actions that destroy individuals of these species or the habitats that are critical to their survival.

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2. The ESA has had a number of successes.

3. These successes have come despite the fact that the US Fish and Wildlife Service and the National Marine Fisheries Service, the agencies that administer the ESA, are perennially underfunded.

4. Today, a number of species are judged by scientists to be in need of ESA protection but have not been added to the endangered species list because government funding is inadequate to help recover them.

5. Polls repeatedly show that most Americans support protecting endangered species.

6. However, the ESA has stopped few development projects—and a number of its provisions and amendments promote cooperation with landowners. a. A landowner and the government can agree to a habitat conservation plan, an arrangement that grants the landowner an “incidental take permit” to harm some individuals of a species if he or she voluntarily improves habitat for the species.

Similarly, in a safe harbor agreement, the government agrees not to mandate additional or different management requirements if the landowner pursues actions that assist a species’ recovery.

C. International treaties promote conservation.

1. The 1973 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) protects rare species by banning the international transport of their body parts.

2. In 1992, the leaders of many nations agreed to the Convention on Biological Diversity, a treaty that aims to help nations conserve biodiversity, use biodiversity in a sustainable manner, and ensure the fair distribution of its benefits.

D. Captive breeding, reintroduction, and cloning are being pursued.

1. Zoos and botanical gardens have become centers for captive breeding in which individuals are bred and raised in controlled conditions with the intent of reintroducing their progeny into the wild.

2. Reintroducing species into areas that they used to inhabit is expensive and resource intensive, but it can pay big dividends.

3. One new idea for saving species from extinction is to create individuals by cloning them.

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E.

Forensics can help to protect species.

1. Forensic science, or forensics, involves the scientific analysis of evidence to make an identification or answer a question relating to a crime or an accident. Conservation biologists are now using forensics to protect species at risk.

F. Several strategies address habitats, communities, and ecosystems.

1. As with endangered species under the ESA, particular species can often serve as tools to conserve habitats, communities, and ecosystems. Such species are called umbrella species because they act as a kind of umbrella to protect many others. Environmental advocacy organizations often use large charismatic vertebrates as flagship species to promote biodiversity conservation.

2. A biodiversity hotspot is a region that supports an especially great number of species that are endemic, found nowhere else in the world.

3. A prime way to conserve habitats, communities, ecosystems, and landscapes is to set aside areas of undeveloped land to be protected as parks and preserves.

4. Protecting natural areas before they become degraded is the best way to safeguard biodiversity and ecological systems. However, in some cases, we can restore degraded natural systems to a semblance of their former condition through the practice of ecological restoration.

G. Community-based conservation is growing.

1. In community-based conservation, biologists actively engage local people in efforts to protect land and wildlife.

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Key Terms background extinction rate biodiversity biodiversity hotspot biological diversity biophilia bioprospecting captive breeding community-based conservation conservation biology Convention on Biological Diversity Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

ecosystem diversity endangered Endangered Species Act (ESA) extinction extirpation forensic science genetic diversity habitat fragmentation mass extinction events poaching Red List species species diversity threatened

Teaching Tips 1. Download the NatureServe 2002 report States of the Union: Ranking America’s Biodiversity (www.natureserve.org/sites/default/files/publications/ files/stateofunions.pdf). NatureServe ranks the 50 states and the District of Columbia based on diversity of species, levels of rarity and risk, endemism, and number of extinct species.

Provide students with information about your state. Then ask them these questions: How does it rank? Is the state high or low in biodiversity? High or low in endemism? High or low in extinction rates? How does it compare to surrounding states?

2. Assign students to research a species that is listed with the current IUCN Red List of Threatened Species (www.iucnredlist.org). Information is accessible via the Red List database through a search by category, region, and/or country.

Where does the species live? What threatens the species? What is the status of the species? What is being done to protect the species?

Species on the Red List are placed in a category based on their status: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Lower Risk, Near Threatened, and Data Deficient. Ask students what they think the categories mean and then provide them with the official definition.

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3. Download an overview of the Endangered Species Act published by the US Fish and Wildlife Service (www.fws.gov/endangered/laws-policies/index.html).

This overview gives basic information about the ESA, including how species become listed, a timeline of major events, how the law is enforced, and how habitat conservation plans are implemented. Ask students to compare the Endangered Species Act with the Red List.

4. A consensogram is a tool that can be used in two ways: for surfacing student misconceptions and also for sharing opinions about a controversial topic. The instructor makes a large bar chart, either on a sheet of paper or on the board. A question is posted above the chart, and possible answers are displayed along the x axis. As students enter the room, have them come to the bar chart, read the question, place a small sticky piece of paper (or fill in a square on the bar chart) atop the bar for their answer choice, and sit down. When all students have made their choices, there will be a bar graph, or histogram, showing the number of students who chose each answer. If the question is commonly misunderstood, such as, “Where does the material for the increase in biomass of a growing plant come from?” (Possible answers: sunlight, water, soil, carbon dioxide in the air, oxygen in the air), then this is an excellent departure point for a lecture on plant growth and photosynthesis. If the question asks for opinions about a topic, such as the preferred method for attempting to preserve a particular endangered species (or not), then it can serve as a good beginning for a class discussion as well.

Additional Resources Websites 1. Conservation International (conservation.org) Conservation International’s website describes its conservation regions, strategies, and programs.

2. Convention on Biological Diversity, United Nations Environment Programme (www.cbd.int/convention) This UN website provides information about the Convention on Biological Diversity, an international treaty to conserve the world’s biodiversity. The full text of the treaty and international case studies can be accessed.

3. National Invasive Species Council, U.S. Department of the Interior (www.doi.gov/invasivespecies/) This online resource gives information about federal efforts concerning invasive species. The website also describes the impacts of invasive species and presents species profiles.

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4. Publications of the IUCN—The World Conservation Union (www.iucn.org/theme/species/publications) This website and its publications discuss and provide information about the efforts of the Species Survival Commission (SSC) to protect species worldwide.

5. The Nature Conservancy (nature.org) This listing provides information about The Nature Conservancy’s programs and success stories around the world.

6. Illinois Biodiversity Basics (www.dnr.illinois.gov/publications/Documents/ 00000289.pdf) Although this focuses on Illinois species, this 164-page document is full of biodiversity activities that could be used in any classroom.

Audiovisual Materials 1. Natural Connections (Classroom Version), 2000, Howard Rosen Productions video, distributed by Bullfrog Films (www.bullfrogfilms.com) This video is divided into five programs: Introduction to Biodiversity; The Significance of Salmon; Keystone Species; Forests, Biodiversity, and You; and Biodiversity vs. Extinction.

2. Evolution: Extinction!, 2001, Public Broadcasting System (www.pbs.org/wgbh/evolution/extinction) The third show in this series addresses what happens when species die. Five mass extinctions have occurred since life began on Earth. Are humans causing the next mass extinction? And what does evolutionary theory predict for the world we will leave to our descendants?

3. Planet in Peril, 2007, CNN (www.cnn.com/services/opk/planet.peril/for.html) This series looks at contemporary issues in biodiversity conservation, overharvesting, and how human population is driving this issue.

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Weighing the Issues Habitat Fragmentation in Your Region Facts to consider: Answers will vary depending on the location of the student.

However, most likely habitat fragmentation has affected the region where the student lives because this is the most damaging impact that human beings have had on ecosystems and biodiversity. How large the fragments are will dictate what animals they can hold. A deer, which is a herbivore, will need a large fragment to graze, or multiple connecting grazing patches. A bear will need even more land because it is a consumer farther up the food chain. Corridors, or protected areas to travel, between patches are necessary for both species. Otherwise, these species will have to encounter human habitats or transportation corridors while moving between patches, putting both humans and the moving animal species at risk.

The Science behind the Story Are Insects Vanishing?

Observation: For years, entomologists have had the sense that the number of insects everywhere has been decreasing.

Study 1: Two studies were undertaken to investigate whether insect numbers were indeed decreasing. In the first study, German armature naturalists of the Entomological Society Krefeld, based in Krefeld, Germany, led by Martin Sorg, collected insects from 63 locations between 1989 and 2016 using malaise traps.

Trapped insects were collected and preserved in alcohol. In 2017, Dutch scientists, led by Caspar Hallman from Radbound University, used statistical analyses to determine whether the biomass in the samples had changed over time.

Results 1: The analyses showed that the average biomass of flying insects in the German samples had decreased by 76% across the 27 years of collection. They also found that the decrease was even greater (82%) for midsummer collections.

Study 2: In the second study, Bradford Lister, a biologist at Rensselaer Polytechnic University in New York, revisited Puerto Rico’s Luquillo rainforest, where he had collected data on the abundance of insects and insect-eating vertebrates in the 1970s. In 2011–2013, he returned with Andres Garcia of the National Autonomous University of Mexico and resampled arthropods in exactly the same ways at exactly the same sites as he had done in the 1970s.

Results 2: The results showed dramatic declines. For arthropods collected by sweeping nets through vegetation, the biomass had declined by 4–8 times. For arthropods caught in sticky traps on the ground and in the canopy, the biomass had 177 ..

fallen 30–60 times. Lister and Garcia also documented steep declines at Luquillo in lizards, frogs, and birds that eat arthropods.

Conclusions: A subsequent literature review revealed that insects are declining worldwide as a result of a variety of causes, including climate change, disease and invasive species, pesticides, fertilizers, pollution, and habitat loss from agriculture.

Can Forensic DNA Analysis Help Save Elephants?

Observation: Customs agents and law enforcement authorities manage to discover and confiscate tons of tusks being shipped internationally in the ivory trade—51 tons in 2013 alone. Yet only a small percentage of tusks are found and confiscated, and poachers are rarely apprehended, so the organized international crime syndicates that run these lucrative operations have been largely unhindered thus far.

Question: Where are elephants being killed, and where are the tusks being shipped?

Hypothesis: Forensic analysis of tissue and dung samples could match poached samples with comparison samples to determine the geographical origin of poached specimens.

Experiment: The researchers began by accumulating 1,350 reference samples of DNA from elephants at 71 locations across 29 African nations. Two subspecies of African elephant exist—savanna elephants, which live in open savannas, and forest elephants, which live in the forests of West and Central Africa. Of the 1,350 genetic samples (from tissues or dung), 1,001 came from savanna elephants and 349 came from forest elephants. Wasser’s teams sequenced DNA from the reference samples and compiled data on 16 highly variable stretches of DNA. For each of the 71 geographic locations, they measured frequencies of alleles (different versions of genes) in these variable DNA stretches. By this process, they created a map of allele frequencies for 71 geographical areas for both types of elephants; this would act as a kind of reference library with which they could compare any samples from tusks confiscated from the ivory trade. Working with law enforcement officials, Wasser was able to access 20% of all ivory seizures made internationally between 1996 and 2005, 28% made between 2006 and 2011, and 61% made between 2012 and 2014. Taking samples from these tusks and sequencing the DNA, Wasser’s teams were then able to compare the results to their library of 71 locations and look for matches. In this way, with the help of sophisticated statistical techniques, they were able to determine the geographical origin of each of the tusks they tested, within an estimated distance of about 300–400 km (185–250 mi).

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Results: For shipments seized between 2006 and 2014, the genetic research indicated a surprisingly clear pattern of two main poaching hotspots. Most forest elephant tusks seized originated from a small region of West-Central Africa where two protected areas overlap the boundaries of four nations. As for savanna elephant tusks, most came from animals in southern Tanzania and northern Mozambique during the early portion of the period. Later in the period, tusks originated from throughout Tanzania, pointing to a shift northward and an increase in poaching in the parks of central and northern Tanzania.

Local Connections Few places on Earth feature wildlife spectacles like those of the Serengeti, but nearly every place on Earth can boast interesting plants and animals and valuable ecosystems. What are some of the plants and animals living in your region that interest you? Are there any that are limited to your region or considered iconic to your region? Describe at least one major type of ecosystem in your area. How do people interact with it? What pressures do its plants and animals experience from human impacts? Can you think of ways in which people could treat natural areas in your region with more care while continuing to thrive socially and economically?

Class time: One class period To begin, have the students generate a list of plants, animals, and ecosystems in your area. This task could be completed individually or in a group. You may want to allow them to use the Internet in order to generate a more diverse set of answers. After students generate their lists, have them work as a group to use the Internet to investigate the pressures these plants, animals, and ecosystems face.

After they identify the pressures, have students create a plan for protecting one of these plants, animals, or ecosystems. At the end of class, have each group present their plan to the class. Allow other students to ask questions after each presentation. Try to encourage students to think about the feasibility of each plan.

How will it be funded? What people or groups might benefit from the plan? What people or groups might be harmed by the plan? Would the plan require legislation?

If so, how realistic would it be for it to be enacted. Etc.

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Calculating Ecological Footprints Footprints and biocapacities in hectares per person

Kenya

Tanzania

United States

Canada

Footprint from grazing land

0.21

0.29

0.32

0.27

Footprint from forest land

0.24

0.21

0.86

1.27

Total ecological footprint

1.02

1.22

8.10

7.74

Percent footprint from grazing and forest

44

41

15

20

Biocapacity of grazing land

0.21

0.29

0.28

0.27

Biocapacity of forest land

0.02

0.14

1.53

8.63

Total biocapacity

0.49

1.02

3.65

15.12

Percent biocapacity from grazing and forest

47

42

50

59

1. Kenya, Tanzania, and Canada are using their grazing land sustainably. The United States and Canada are using their forest land sustainably.

2. Forest use and grazing comprise a larger part of the footprint in tropical-zone developing nations such as Kenya and Tanzania. There is a large difference between these two types of nations–one group is developing, one is developed.

One relies more on commodities grown in their own nations while the other relies more on imports.

3. Because the Living Planet Index expresses how large the average population size of a species is now relative to its size in the year 1970, it appears that biodiversity loss has been most marked in Kenya and Tanzania because the index in tropical regions declined by a larger percent.

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12 Forests, Forest Management, and Protected Areas Chapter Objectives This chapter will help students: Summarize the ecological and economic contributions of forests Outline the history and current scale of deforestation Assess the dynamics of timber harvest management Discuss forest management in relation to fire, pests, and climate change, and evaluate sustainable forestry certification Identify federal land management agencies and the lands they manage Recognize types of parks and protected areas Evaluate challenges to the effectiveness of parks and protected areas

Lecture Outline I.

Central Case Study: Saving the World’s Greatest Rainforest A. The Amazon rainforest is a critical component of Earth’s biosphere. It encompasses most of the rainforest on Earth; it captures water, regulates climate, stores carbon, hosts thousands of species of plants and animals, and is home to tribes of indigenous people.

B. Nearly two-thirds of the Amazon rainforest is within Brazil. Since the 1800s, Brazil has been encouraging development in the Amazon, including farming and ranching. Each new road allows access for miners, loggers, and poachers, many of whom exploit resources illegally.

C. From 1970–2008, an average of nearly 17,000 km2 were cleared each year in Brazil. Over the last 50 years, more than one-fifth of the forest has been cleared.

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D. In 2003–2004, international pressure caused the Brazilian government to strengthen enforcement of the nation’s Forest Code and to establish other forest-protection measures.

E. International pressure also convinced banks to require landowners to document compliance with environmental regulations to get loans. In addition, it persuaded purchasers of beef, leather, and soy to buy only those certified as sustainable. As a result of these factors, deforestation rates fell after 2009 to an average of 6500 km2 per year.

F. In 2018, Brazil elected Jair Bolsonaro, an autocratic right-wing populist who vowed to open the Amazon to a new wave of development. Under Bolsonaro, deforestation began to rise.

G. In addition to human development, the Amazon rainforest faces challenges from global climate change and the accompanying droughts and fires.

II.

Forest Ecosystems and Forest Resources 1. A forest is any ecosystem with a high density of trees.

A. There are many types of forests.

1. Ecologists and forest managers find it useful to classify forests into forest types, categories defined by their predominant tree species.

2. Altogether, forests currently cover 31% of Earth’s land surface.

B. Forests are ecologically complex.

1. Because of their structural complexity and their capacity to provide many niches for organisms, forests comprise some of the richest ecosystems for biodiversity.

2. In a forest’s canopy—the upper level of leaves and branches in the treetops—beetles, caterpillars, and other leaf-eating insects abound, providing food for birds such as warblers and tanagers while arboreal mammals from squirrels to sloths to monkeys consume fruits and leaves. Animals also live and feed in the subcanopy (the middle portion of a forest beneath the tree crowns of the canopy), in shrubs and small trees of the understory (the shaded lower level of a forest), and among groundcover plants on the forest floor.

3. Cavities in trunks and limbs provide nest and shelter sites for a wide variety of animals. Dead and dying trees (called snags) are especially valuable; insects that break down the wood provide food for woodpeckers, which create cavities that other animals may later use.

Fallen trees create openings called treefall gaps, letting sunlight through past the canopy and down to the forest floor, encouraging the growth of early successional plants and creating habitat diversity within the forest.

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4. Forests with a greater diversity of plants tend to host a greater diversity of organisms overall.

C. Forests provide ecosystem services.

D. Carbon storage limits climate change.

E. Forests provide us valuable resources.

III.

Forest Loss 1. Deforestation is the clearing and loss of forests.

A. Agriculture and demand for wood put pressure on forests.

1. Forest clearing has fed our civilization’s growth, but the loss of forests also exerts damaging impacts as our human population grows.

B. We deforested much of North America.

1. Deforestation for timber and farmland propelled the expansion of the United States and Canada westward across the North American continent.

2. As a farming economy shifted to an industrial one, wood was used to stoke the furnaces of industry.

3. By the 20th century, very little primary forest—natural forest uncut by people—remained in the lower 48 US states, and today even less is left. a. Nearly all the largest oaks and maples found in eastern North America today, and even most redwoods of the California coast, are second-growth trees: trees that have sprouted and grown to partial maturity after old-growth trees were cut. Second-growth trees characterize secondary forest.

C. Forests are being cleared most rapidly in developing nations.

1. Today’s powerful industrial technologies allow these nations to exploit their resources and push back their frontiers even faster than occurred in North America. Deforestation is rapid today in places such as Indonesia, Africa, Central America, and South America.

2. Developing nations are striving to expand settlement for their burgeoning populations and boost their economies by extracting natural resources.

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3. Developing nations often are desperate enough for economic development and foreign capital that they impose few restrictions on logging. a. Often they allow their timber to be extracted by foreign multinational corporations, which pay fees for a concession, or right to extract the resource.

D. Solutions are emerging.

1. Some conservation proponents are pursuing community-based conservation projects that empower local people to act as stewards of their forest resources. In other cases, conservation organizations are buying concessions and using them to preserve forest rather than to cut it down. In such a conservation concession, the nation receives money and keeps its natural resources intact.

2. Another approach is the debt-for-nature swap. In this approach, a conservation organization or other entity offers to pay off a portion of a developing nation’s international debt in exchange for a promise by the nation to set aside forest reserves, fund environmental education, and better manage protected areas.

3. Carbon offsets and other financial incentives are central to emerging international plans to curb deforestation and climate change. Across a decade’s worth of international climate conferences, negotiators have outlined a proposed program called Reducing Emissions from Deforestation and Forest Degradation (REDD, soon changed to REDD+ as the program expanded in scope), whereby wealthy industrialized nations pay poorer developing nations to conserve forest.

IV.

Forest Management 1. Foresters are professionals who manage forests through the practice of forestry, and they must balance our society’s demand for forest products against the central importance of forests as ecosystems.

A. Forest management is one type of resource management.

1. Resource management describes our use of strategies to manage and regulate the harvest of renewable resources.

B. Resource managers follow several strategies.

1. The maximum amount of resource extraction without depleting the resource from one harvest to the next is known as the maximum sustainable yield.

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2. More managers espouse ecosystem-based management, which aims to minimize the impact on ecosystems and ecological processes that provide the resource.

3. Adaptive management involves systematically testing different approaches and aiming to improve methods through time.

C. Fear of a “timber famine” inspired national forests.

1. The depletion of forests throughout the Eastern United States prompted the federal government to form a system of forest reserves: public lands set aside to grow trees, produce timber, and protect water quality. Today the US national forest system, managed by the US Forest Service, covers more than 8% of the nation’s land area.

D. We extract timber from private and public lands.

1. Today, almost 90% of the timber harvesting in the United States takes place on private land owned by the timber industry or by small landowners. Private timber companies also extract timber from the US national forests and from publicly held state forests.

2. Overall, timber harvesting in the United States and other developed nations has remained stable for the past half-century while it has more than doubled in developing nations.

3. When regrowth outpaces removal, the character of forests may change. Once primary forest is replaced by younger secondary forest or by single-species plantations, the resulting community may be very different, and generally it is less ecologically valuable.

E. Plantation forestry has grown.

1. Today’s timber industry focuses on production from plantations of fast-growing tree species planted in single-species monocultures.

All trees in a stand are planted at the same time, so the stands are even-aged; that is, all trees are the same age.

2. Because there are few tree species and little variation in tree age, plantations do not offer habitat to many forest organisms.

3. Some harvesting methods aim to maintain uneven-aged stands, in which a mix of ages (and often a mix of tree species) creates greater structural diversity and makes the stand more similar to a natural forest.

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F. We harvest timber in several ways.

1. In the simplest method, clearcutting, all trees in an area are cut at once. Clearcutting is cost efficient, and to some extent it can mimic natural disturbance events such as fires, tornadoes, or windstorms.

However, the ecological impacts of clearcutting are considerable.

2. In the seed-tree approach, small numbers of mature and vigorous seed-producing trees are left standing so that they can reseed the logged area. In the shelterwood approach, small numbers of mature trees are left to provide shelter for seedlings as they grow.

3. Selection systems allow uneven-aged stand management because only some trees are cut at any one time.

4. All timber-harvesting methods disturb soil, alter habitat, and affect plants and animals. All methods modify forest structure and composition.

G. Forest management has evolved over time.

1. The US Forest Service has nominally been guided by the policy of multiple use, meaning that national forests were to be managed for recreation, wildlife habitat, mineral extraction, and various other uses.

2. In 1976, the US Congress passed the National Forest Management Act. This act mandated the management of every national forest to draw up plans for renewable resource management based on the concepts of multiple use and maximum sustainable yield and subject to public input under the National Environmental Policy Act. 3. Timber harvesting methods were brought more in line with ecosystem-based management goals. A set of approaches dubbed new forestry called for timber cuts that mimicked natural disturbances.

4. Another policy milestone that signaled a shift toward conservation occurred in 2001, when President Bill Clinton issued an executive order that became known as the roadless rule. The roadless rule put 23.7 million hectares (58.5 million acres)—31% of national forest land and 2% of total US land—off-limits to road construction or maintenance (and thus to logging).

H. Fire can hurt or help forests.

1. For more than a century, the Forest Service and other agencies suppressed fire whenever and wherever it broke out.

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2. Fire suppression increases the likelihood of catastrophic fires that damage forests, destroy property, and threaten human lives. At the same time, increased residential development alongside forested land—in the wildland-urban interface—is placing more homes in fire-prone situations.

3. To reduce fuel loads, protect property, and improve the condition of forests, land management agencies now burn areas of forest intentionally with low-intensity fires under carefully controlled conditions. Such prescribed fire clears away fuel loads, nourishes the soil with ash, and encourages the vigorous growth of new vegetation.

4. In the wake of major fires in California in 2003, the US Congress passed the Healthy Forests Restoration Act, which encourages prescribed fire and salvage logging, the physical removal of small trees, underbrush, and dead trees by timber companies, following a natural disturbance.

I. Climate change and pest outbreaks are altering forests.

1. Global climate change is now worsening the wildfire risk by bringing warmer weather to North America and drier weather to the American West.

2. Pest insects such as bark beetles, which feed within the bark of conifer trees, are adding to the wildfire risk.

3. Scientists studying beetles and their impacts say that there are two primary reasons for today’s unprecedented outbreaks. a. The first reason is that past forest management has resulted in even-aged forests across large regions, and many trees in these forests are now at a prime age for beetle infestation. b. The second reason is climate change.

J. Sustainable forestry is gaining ground.

1. Organizations such as the FSC examine practices and rate them against criteria for sustainability. They grant sustainable forest certification to forests, companies, and products using methods that they judge to be sustainable.

2. Pursuing sustainable forestry practices is often more costly for producers, but producers recoup these costs when consumers pay more for certified products.

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V.

Parks and Protected Areas A. Why create parks and reserves?

1. People establish parks and protected areas for several reasons. a. Inspiration from enormous or unusual scenic features. b. Hiking, fishing, hunting, kayaking, bird-watching, and other recreation. c. Revenue from ecotourism. d. Health, peace of mind, exploration, wonder, and spiritual solace. e. Utilitarian benefits and ecosystem services (such as how forested watersheds provide cities with clean drinking water and a buffer against floods). f. Refuges for biodiversity, helping to maintain populations, communities, and ecosystems.

B. Parks and reserves were pioneered in the United States.

1. The striking scenery of the American West persuaded the US government to create the world’s first national parks, public lands protected from resource extraction and development but open to nature appreciation and recreation.

2. The National Park Service was created in 1916 to administer the growing system of parks and monuments, which today numbers 408 units totaling more than 34 million hectares (84 million acres) and includes national historic sites, national recreation areas, national seashores, and other areas.

3. A national wildlife refuge is another type of federal protected area.

4. The US Fish and Wildlife Service administers the national wildlife refuges.

5. In response to the public’s desire for undeveloped areas of land, in 1964 Congress passed the Wilderness Act, which allowed some areas of existing federal lands to be designated as wilderness areas. These areas are off-limits to development but open to hiking, nature study, and other low-impact public recreation.

C. Not everyone supports setting land aside.

1. The restriction of activities in wilderness areas has generated some opposition to US land protection policies, especially among citizens and policymakers in Western states.

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2. Parks and protected areas regularly bring substantial economic benefit to people who live nearby, through ecotourism. However, individuals who do not have jobs related to parks and tourism may feel that a park restricts their economic opportunities.

3. Groups of indigenous people frequently oppose government actions to set aside land.

4. However, protected areas sometimes serve the interests of indigenous people.

D. Many agencies and groups protect land.

1. Private nonprofit groups also preserve land. Land trusts are local or regional organizations that purchase land to preserve it in its natural condition.

E. Protected areas are increasing internationally.

1. Many nations have established systems of protected areas and are benefiting from ecotourism as a result.

2. Many of the world’s protected areas are merely paper parks— protected on paper but not in reality.

3. Biosphere reserves are tracts of land with exceptional biodiversity that couple preservation with sustainable development to benefit local people.

4. World heritage sites are another type of international protected area.

5. Some transboundary reserves function as peace parks, helping to ease tensions by acting as buffers between nations with historical boundary disputes.

F. How much protected area is needed?

1. The is no single right or wrong answer to this question. The official target for 2020 among nations under the Convention on Biological Diversity is for 17% of the land area and 10% of the marine and coastal area to be set aside for protection. However, the esteemed scientist E. O. Wilson and many of his colleagues, citing extensive research in conservation biology, argue that “the only way to reverse the extinction crisis is through a conservation moonshot … to keep half the land and half the sea of the planet as wild and protected from human intervention or activity as possible.”

G. Habitat fragmentation makes preserves more vital.

1. When forests are fragmented, many species suffer. For some, a fragment may simply not contain enough area. For other species, 189 ..

the problem may lie with edge effects, impacts that result because the conditions along a fragment’s edge differ from conditions in the interior.

H. Insights from islands warn us of habitat fragmentation.

1. The island biogeography theory explains how species come to be distributed among oceanic islands.

2. Island biogeography theory explains how the number of species on an island results from a balance between the number added by immigration and the number lost through extirpation. It predicts an island’s species richness based on the island’s size and its distance from the mainland. a. The farther an island lies from a continent, the fewer species tend to find and colonize it. Thus, remote islands host few species because of low immigration rates. b. Larger islands have higher immigration rates because they present fatter targets for dispersing organisms to encounter. c. Larger islands have lower extinction rates because more space allows for larger populations, which are less likely to drop to zero by chance.

3. Together, the latter two trends give large islands more species than small islands. Very roughly, the number of species on an island is expected to double as island size increases tenfold. This is illustrated by species-area curves.

4. These patterns hold up for terrestrial habitat islands as well, such as forests fragmented by logging and road-building.

I. Reserve design has consequences for biodiversity.

1. Conservation biologists debate the SLOSS issue (for “single large or several small”).

2. A related issue is how effectively corridors of protected land allow animals to travel between islands of habitat.

J. Climate change threatens protected areas.

1. As temperatures become warmer, species ranges shift toward cooler climes: toward the poles and upward in elevation.

2. In a landscape of fragmented habitat, some organisms may be unable to move from one fragment to another.

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Key Terms adaptive management biosphere reserves canopy clear-cutting concession conservation concession corridors debt-for-nature swap deforestation ecosystem-based management edge effects even-aged forest forestry forest types island biogeography theory land trusts maximum sustainable yield multiple use national forest National Forest Management Act national parks national wildlife refuge

new forestry prescribed fire primary forest Reducing Emissions from Deforestation and Forest Degradation (REDD+) resource management roadless rule salvage logging secondary forest seed tree selection systems shelterwood SLOSS dilemma snags species-area curves subcanopy sustainable forest certification understory uneven-aged wilderness areas wildland-urban interface World heritage sites

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Teaching Tips 1. Provide students with information about the three categories of public lands.

• Multiple-use lands: These public lands are the National Forests, managed by the US Forest Service, and National Resource Lands, managed by the Bureau of Land Management. Consumptive activities such as mining, logging, and grazing are allowed.

• Moderately restricted-use lands: National Wildlife Refuges, managed by the US Fish and Wildlife Service, are in this category. Consumptive activities are allowed, but on a case-by-case basis.

• Restricted-use lands: These lands are the National Parks, managed by the National Park Service, and wilderness areas. No consumptive activities are allowed in these areas. No motor vehicles are allowed in wilderness areas (roadless areas).

• Ask students to compare the management philosophies of the US Forest Service with those of the National Park Service. Note: The USFS is under the purview of the US Department of Agriculture while the National Park Service is an agency within the Department of the Interior. Ask students whether that matters and why.

2. Have students learn about land stewardship, land trusts, and private groups that are attempting to either use the land sustainably or preserve it in a natural state.

Ask students to read the goals or covenants of the following three groups, and compare them: • The Nature Conservancy (nature.org) is the largest of the national groups, seeking to purchase and preserve fragile habitats. By its very size, it is unable to protect many smaller parcels that do not fit into its overall mission.

• The Malpai Borderlands Group (www.malpaiborderlandsgroup.org) is an intermediate-sized organization spread across two states along the border with Mexico. This organization primarily includes ranchers who are “working to encourage profitable ranching and other traditional livelihoods, which will sustain the open space nature of our land for generations to come.”

• The Saguaro-Juniper Corporation (www.saguaro-juniper.com) is a small, nonprofit organization made up of writers, philosophers, small ranchers, and scientists. They purchase land in sensitive areas along watersheds and are dedicated to maintaining “… earth, waters, plants, and animals in a way that promotes the health, stability, and diversity of the whole community. Thus we do not seek to isolate wildlands from all human contact; rather, we hope to include human beings as partners embracing the land, its plants, and animals.”

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Are there similar groups in your area? Have your students investigate and report on such groups.

3. Ask students to investigate land use patterns in your state. There is a National Land Cover Dataset available online at landcover.usgs.gov. This dataset is based on a 21-class land cover classification scheme that details the coverage of water, forests, scrublands, barren areas, wetlands, grasslands, cultivated areas, and developed areas in each state. The land use statistics can be accessed free of charge. The data were retrieved from Landsat remote-sensed images of Earth’s land surface.

Ask students to compute the percentage of cover for each land cover class. Ask them: What are the dominant land cover classes? Do residential and commercial developments cover a large percentage of the land in your state?

Alternatively, ask them to choose a country and use the global forest cover and global forest canopy density database to analyze the forest coverage as of 2000.

4. Have students research the issues surrounding forest fires—natural wildfires, human-caused accidental or arson fires, and controlled burns. For a good international overview, there is a short statement from the International Cooperation on Forest Fire Management meeting, held in March 2005 by the United Nations’ Food and Agriculture Organization (www.fao.org/docrep/ meeting/009/j3939e/j3939e00.htm).

Students can look at background and policy websites such as the Canadian government website www.cprn.org/index.cfm. They can find out what was done in their area before, during, and after fires. Some states and communities have active prevention programs that employ forest thinning and brush removal around homes and buildings in fire-prone areas. After a fire has occurred, there are many issues that need to be addressed, from reseeding and soil erosion control measures to the rescue of large animals, especially top predators, who may have been injured or without a reliable food source and are in need of assistance and possible relocation. Ask students whether loggers are allowed to come in for some types of snag removal. If so, on what basis and for how long?

5. Discuss with your students the difference between “what the data say” and “what the data mean.” Divide the students into groups and give them a dataset.

Have them list at least five things that the data say, putting these statements on the board. For example, they might write “Deforestation was much worse in Africa than in Latin America and the Caribbean over the period from 1990 to 2000.”

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Next, ask students to interpret what the data mean. They should be able to discuss a variety of issues, such as: •

What does the deforestation rate in Africa mean for the animals that live there?

•

What does it mean for the villages at the edges of forests whose inhabitants depend on the forests for raw materials, fruits, hunting, and water?

•

Does deforestation mean that the villagers are becoming wealthy by selling the forest products? If not, who is benefiting?

Additional Resources Websites 1. Healthy Forests Initiative, Forest Service, US Department of Agriculture (www.fs.fed.us/projects/hfi) This website provides general information about President George W. Bush’s Healthy Forests Initiative, which aims to reduce the threat and damage sustained from forest fires by thinning forests.

2. ParkNet, the National Park Service, US Department of the Interior (www.nps.gov) This resource has a wealth of information about the national parks managed by the NPS, including the nature, culture, history, and science of each park. There is also a link for educators.

3. Forest Management, Forest Service, US Department of Agriculture (www.fs.fed.us/forestmanagement/index.shtml) This gateway has links to the Forest Service’s forest management program.

4. National Forest Management Act, USDA Forest Service (http://www.fs.fed.us/emc/nfma/includes/NFMA1976.pdf) This website provides the full text of the National Forest Management Act of 1976.

Audiovisual Materials 1. In Good Hands: Culture and Agriculture in the Lacandon Rainforest, 1994, produced by Jaime Kibber and distributed by The Video Project (www.videoproject.com) This video follows Dr. James Nations as he works with the Lacandon Maya of Chiapas in southern Mexico, who have been practicing a sustainable form of rainforest farming for centuries.

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2. Battle for the Trees, 1993, produced by Lisa Malcolm and Jack Silberman, found at the National Film Board of Canada (www.onf-nfb.gc.ca/eng/ collection/film/?id=29464) This program documents the fight to preserve British Columbia’s old-growth forest from clear-cut logging.

3. World’s Last Great Places: Rainforests, 2007, National Geographic Home Video This program is part of the series The World’s Last Great Places and features one of the world’s last great wilderness regions—the tropical rainforest.

4. Living Edens: Yellowstone, America’s Sacred Wilderness, 1997, PBS Home Video (www.pbs.org/edens/yellowstone) This video is one show in the series The Living Edens. A naturalist shows viewers the natural events of each season in Yellowstone National Park.

5. Whose Home on the Range?, 2000, produced by Ben Daitz and distributed by Bullfrog Films (www.bullfrogfilms.com) This video describes the peace process among environmentalists, ranchers, and the US Forest Service in Catron County, New Mexico, “the toughest county in the West.”

Weighing the Issues Logging Here or There Facts to consider: Answers will vary. One possible response would be based on a NIMBY attitude (i.e., don’t log forests near my home—go someplace else to log your trees). However, the impact of logging in developing countries is much more severe than it is in developed countries. Due to the extreme need for economic advancement in developing countries, there is little or no regulation and oversight of logging operations.

In addition, most logging firms are foreign to the developing country and have no incentive to log forests in a sustainable way. While there may be a temporary, shortterm, regionally based economic upturn with local employment from low-paying and dangerous jobs, most of the profit goes out of the country because the wood is exported.

Once the forest is gone, so is the economic upswing. Finally, the harm to indigenous people can be devastating as the forest and its resources on which they base their way of life are eliminated. In other words, forcing the company to go to a developing country would cause more harm on a global scale than if the company conducted logging in its own backyard.

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A different approach would be a more cooperative one in which activists and loggers work together to develop and use sustainable logging methods in the local, old-growth forest. Such a compromise is easier for developed countries as there are more resources, both personal and financial, to commit to such an endeavor.

How to Handle Fire?

Facts to consider: Responses will vary and require an individual answer. Some information students may wish to use to develop a response can be found at the Forest Fires website of the Environmental Literacy Council (www.enviroliteracy.org/article.php/46.html). One approach to this problem may be to partition preventive resources—increasing citizen involvement and predicting where the danger areas are to locate assets that can minimize the damage from fires. Satellite imagery can pinpoint where extreme fire hazard areas are, and then community action can do preventive work such as clearing brush from around homes. This will allow fire professionals to concentrate on the larger picture by assessing the fuel load on the ground, managing prescribed burns, coordinating assets in case of a fire, and so on.

Large-scale maps of possible fire areas may allow government and private fire professionals to centrally locate firefighting assets for a quick response.

The Science behind the Story What Happens When a Forest Is Fragmented?

Observation: Plants, animals, and ecosystems are affected when we fragment a forest.

Question: How can island biogeography theory be applied to forested landscapes being fragmented by development? How large do fragments have to be to retain their species?

Study: Dr. Thomas Lovejoy’s team of Brazilians and Americans worked out a deal with Brazil’s government: Ranchers could clear some forest within the study area if they left square plots of forest standing as fragments within those clearings.

By this process, 11 fragments of three sizes (1 hectare [2.5 acres], 10 hectares [25 acres], and 100 hectares [250 acres]) were left standing, isolated as “islands” of forest, surrounded by “seas” of cattle pasture. Each fragment was fenced to keep cattle out. Then 12 study plots (of 1, 10, 100, and 1,000 hectares) were established within the large expanses of continuous forest still surrounding the pastures to serve as control plots against which the fragments could be compared.

Besides comparing treatments (fragments) and controls (continuous forest), the project also surveyed populations in fragments before and after they were isolated.

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Results: With these data on trees, birds, mammals, amphibians, and invertebrates, they documented declines in the diversity of most groups. As researchers studied the fragments over the years, they found that small ones lost more species, and lost them faster, than large fragments—just as island biogeography theory predicts.

Fragments distant from continuous forest lost more species, as predicted by island biogeography theory, but data revealed that even very small openings can stop organisms that are adapted to the deep interior forest from dispersing to recolonize fragments. Also, it was realized that secondary forests that sprang up from past pastureland began to link these islands, serving as a corridor between them.

Implication: Impacts across the Amazon will be more severe than the impacts revealed by their experiments. This is because most real-life fragments, unlike the experimental ones, (1) are not protected from hunting, logging, mining, and fires; (2) do not have secondary forest to provide connectivity; (3) are not near large tracts of continuous forest that provide recolonizing species and maintain humidity and rainfall; and (4) are not square in shape, so they feature more edge. Insights from these projects are helping scientists and policymakers strategize how best to conserve biodiversity amid continued pressures on forests.

Local Connections Identify an area of forest in your region, and learn what you can about its history.

Is it primary forest or secondary forest? Was it always the size it is now, or has some area been lost or gained? Is forest (or other natural habitat) in your region becoming more fragmented over time? If so, what could be done to prevent further fragmentation while improving the quality of life for people living in the area?

Now consider a park or protected area in your region. What benefits does it bring to people living nearby? Would you like to see more or fewer, larger or smaller, parks and protected areas in your region? Why? Class time: Could be completed over one class period or as a homework assignment.

To begin, allow students to use the Internet to identify a forest in your region.

Depending on the forest, there may be information online about its history. For many areas, Google Earth has time sequence aerial imagery for the last 30+ years.

Remind students that they should look for changes in the size of the forest and for signs of forest fragmentation, such as roads, power lines, and rail lines. If students are working on the activity during class, they could work in groups to development sustainable management solutions for this forest tract.

Allow students to identify a park or protected area in your region. You may want to steer them towards a rural, natural park, but urban, managed parks also provide important ecosystem services. It may be interesting for students, many of whom live in the urban environment, to learn more about how urban parks affect the area around them. If students are working on the activity during class, they could discuss 197 ..

future park sizes and locations in the region. Encourage students to think about the feasibility of their plan. What groups of people would be affected? How would they finance their plan? Would there be plants and/or animals that would be especially impacted (positively or negatively) by the plan? Etc.

Calculating Ecological Footprints Population (millions)

Total paper consumed (millions of metric tons)

Per capita paper consumed (pounds)

Africa

1,203

8

15

Asia

4,437

199

99

Europe

740

93

277

Latin America

637

28

97

North America

360

76

466

Oceania

40

4

221

World

7,418

407

121

1. If everyone used paper like North Americans, 1,568 million metric tons of paper would be consumed.

2. About 59% of paper would be saved if North Americans used paper like Europeans. About 97% of paper would be saved if North Americans used paper like Africans.

3. Answers will vary, but North Americans tend to consume more resources than people of other regions, in part because our affluence has encouraged a throwaway mentality. An individual can reduce consumption by buying recycled paper products rather than virgin ones, using electronic means of communicating information in place of print means where possible, and using one’s own coffee cups and cloth grocery bags in place of paper ones, among other measures.

4. By using FSC-certified paper, one is making the commitment to better water quality, lessen soil erosion, and lessen pesticide use on the planet.

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13 The Urban Environment: Creating Sustainable Cities Chapter Objectives This chapter will help students: Describe the scale of urbanization Define sprawl and discuss its causes and consequences Outline city and regional planning and land use strategies Evaluate transportation options, urban parks, and green buildings Analyze environmental impacts and the advantages of urban centers Assess urban ecology and the pursuit of sustainable cities

Lecture Outline I.

Central Case Study: Managing Growth in Portland, Oregon A. Oregon’s law required comprehensive land use plans, including an urban growth boundary (UGB), separating urban and rural areas.

B. The Metropolitan Service District, or Metro, focused growth on existing urban centers and on building communities where people can walk, bike, or take mass transit between home, work, and shopping.

C. To many Portlanders today, the UGB remains the key to maintaining quality of life in city and countryside alike.

D. Opponents of Ballot Measure 37, requiring that landowners be compensated if the value of their land is decreased by government regulation, began to have misgivings.

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E. Oregon’s voters passed Ballot Measure 49 in 2007. It protects the rights of small landowners to gain income from their property by developing small numbers of homes while restricting large-scale development and development in sensitive natural areas.

F. In 2010, Metro finalized a historic agreement with its region’s three counties to determine where urban growth will be allowed over the next 50 years. Metro and the counties apportioned more than 121,000 hectares (300,000 acres) of undeveloped land into “urban reserves” open for development and “rural reserves” where farmland and forests would be preserved, precisely mapping the boundaries. The hope is that this agreement will give clarity and direction for landowners and governments alike for half a century.

II.

Our Urbanizing World 1. As we undergo this historic shift from the countryside into towns and cities—a process called urbanization—two pursuits become ever more important. a. One is to make our urban areas more livable by meeting residents’ needs for a safe, clean, healthy urban environment and a high quality of life. b. The other is to make urban areas sustainable by creating cities that can prosper in the long term while minimizing ecological impacts.

A. Industrialization drove urbanization.

1. Urban populations are growing because the human population overall is growing and more people are moving from farms to cities than are moving from cities to farms.

2. Industrialization and urbanization bred further technological advances that increased production efficiencies, both on the farm and in the city. This process of positive feedback continues today.

3. In developed nations such as the United States, urbanization has slowed because three of every four people already live in cities, towns, and suburbs—the smaller communities that ring cities.

4. In contrast, today’s developing nations, where most people still reside on farms, are urbanizing rapidly.

B. Environmental factors influence the location of urban areas.

1. Well-located cities often serve as linchpins in trading networks, funneling in resources from agricultural regions, processing them, manufacturing products, and shipping those products to other markets.

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2. Powerful technologies and cheap transportation enabled by fossil fuels have allowed cities to thrive even in resource-poor regions.

C. People moved to suburbs.

1. American cities grew rapidly throughout the 19th and early 20th centuries as a result of immigration from abroad and increased trade as the nation expanded westward. The bustling economic activity of downtown districts held people in cities despite crowding, poverty, and crime.

2. As affluent people moved outward into the expanding suburbs, jobs followed.

3. The exodus to the suburbs in 20th century America was aided by the rise of the automobile, an expanding road network, and inexpensive and abundant oil.

4. Today, technology and social trends are reinforcing the spread of suburban areas and are driving people still farther out to exurbs, regions beyond the suburbs generally inhabited by affluent individuals seeking even more space than the suburbs provide.

5. By allotting more space to each person, suburban and exurban growth has spread human impact across the landscape.

III.

Sprawl 1. Sprawl refers to the spread of low-density urban, suburban, or exurban development outward from an urban center.

A. Urban areas spread outward.

B. Sprawl has several causes.

1. There are two main components of sprawl. a. One is human population growth. b. The other is per capita land consumption.

2. Economists and politicians have encouraged the unbridled spatial expansion of cities and suburbs.

C. What is wrong with sprawl?

1. Transportation—Sprawl constrains transportation options.

2. Pollution—Sprawl increases pollution by promoting automobile transportation.

3. Health—Driving cars largely takes the place of walking, so sprawl promotes physical inactivity.

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4. Land use—More land is developed while less is left as forests, fields, farmland, or ranchland.

5. Economics—Sprawl drains tax dollars from communities and funnels money into infrastructure for new development on the fringes of those communities.

IV.

Creating Livable Cities A. Planning helps to create livable urban areas.

1. City planning (or urban planning) is the professional pursuit that attempts to design cities to maximize their efficiency, functionality, and beauty.

2. In today’s world of sprawling metropolitan areas, regional planning has become as important as city planning.

B. Zoning is a key tool for planning.

1. Zoning is the practice of classifying areas for different types of development and land use.

2. Zoning involves government restriction on the use of private land and represents a constraint on personal property rights. For this reason, some people consider zoning a regulatory taking that violates individual freedoms.

C. Urban growth boundaries are now widely used.

1. Planners in Oregon put limits on sprawl by containing growth largely within existing urbanized areas. They did this by establishing urban growth boundaries, lines on a map that separate areas zoned to be high density and urban from areas intended to remain low density and rural. Oregon’s urban growth boundaries (UGBs) have aimed to revitalize downtowns; protect working farms, orchards, ranches, and forests; and ensure urban-dwellers some access to open space.

2. UGBs reduce the amounts that municipalities need to pay for infrastructure, compared with the amounts required by sprawling areas.

3. Today in Portland, demand for housing exceeds supply, rents are soaring, and low- and middle-income people are being forced out of neighborhoods where they have lived for years as these neighborhoods experience gentrification, a transformation to conditions that cater to wealthier people.

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D. Smart growth and new urbanism aim to counter sprawl.

1. Urban growth boundaries and other approaches from these policies have coalesced under the concept of smart growth.

2. Proponents of smart growth aim to rejuvenate the older existing communities that so often are drained and impoverished by sprawl.

3. A related approach among architects, planners, and developers is new urbanism, which seeks to design neighborhoods on a walkable scale, with homes, businesses, schools, and other amenities all nearby for convenience.

4. New urbanist neighborhoods are generally served by public transit systems. In transit-oriented development, compact communities in the new urbanist style are arrayed around stops on a rail line, enabling people to travel most places they need to go by train and foot alone.

E. Transit options help cities.

1. A key ingredient in any planner’s recipe for improving the quality of urban life is to give residents alternative transportation options.

2. Bicycle transportation is one key option.

3. Other transportation options include mass transit systems: public systems of buses, trains, subways, or light rail (smaller rail systems powered by electricity) that move large numbers of passengers while easing traffic congestion, taking up less space than road networks, and emitting less pollution than cars.

4. The United States lags behind most nations in mass transit.

5. Establishing mass transit is not easy.

F. Urban residents need park lands.

1. Natural lands, public parks, and open space provide greenery, scenic beauty, freedom of movement, and places for recreation. These lands also keep ecological processes functioning by helping to regulate climate, purify air and water, and provide wildlife habitat.

G. Park lands come in various types.

1. Playgrounds give children places to be active outdoors and interact with their peers. Community gardens allow people to grow vegetables and flowers in a neighborhood setting.

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2. Greenways are strips of land that connect parks or neighborhoods; often run along rivers, streams, or canals; and provide access to walking trails.

3. Greenbelts are long and wide corridors of park lands, often encircling an entire urban area.

H. Green buildings bring benefits.

1. There is a thriving movement in architecture and construction to design and build green buildings, structures meant to minimize the ecological footprint of their construction and operation.

2. The US Green Building Council promotes these efforts by running the Leadership in Energy and Environmental Design (LEED) certification program.

3. Green building techniques add expense to construction.

4. Schools, colleges, and universities are leaders in sustainable building.

V.

Urban Sustainability A. Urban resource consumption brings a mix of environmental effects.

1. Urbanization brings a complex mix of consequences. a. Resource sinks—Cities and towns are sinks for resources, having to import from source areas beyond their borders nearly everything they need to feed, clothe, and house their inhabitants and power their commerce. b. Efficiency—Once resources arrive at an urban center, the concentration of people allows goods and services to be delivered efficiently. c. More consumption—The ecological footprints of cities are much greater than their actual land areas.

B. Urbanization preserves land.

C. Urban centers suffer and export pollution.

1. Not all waste and pollution leave the city. Urban dwellers are exposed to heavy metals, industrial compounds, and chemicals from manufactured products that accumulate in soil and water.

2. City residents suffer thermal pollution as well because cities tend to have ambient temperatures that are several degrees higher than those of surrounding areas. This urban heat island effect results from the concentration of heat-generating buildings, vehicles, factories, and people.

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3. Noise pollution consists of undesired ambient sound. Excess noise degrades one’s surroundings aesthetically, can cause stress, and at intense levels (such as with prolonged exposure to the sounds of leaf blowers, lawn mowers, and jackhammers) can harm hearing.

4. The glow of light pollution from city lights may impair sleep and obscure the night sky, impeding the visibility of stars.

D. Urban centers foster innovation.

E. Urban ecology helps cities move toward sustainability.

1. Researchers in the field of urban ecology hold that cities can be viewed explicitly as ecosystems and that the fundamentals of ecosystem ecology and systems science apply to the urban environment.

F. Steps toward livability enhance sustainability.

Key Terms city planning exurbs gentrification green buildings greenbelts greenways Leadership in Energy and Environmental Design (LEED) light pollution mass transit new urbanism noise pollution

regional planning smart growth sprawl suburbs transit-oriented development urban ecology urban growth boundaries (UGBs) urban heat island effect urban planning urbanization zoning

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Teaching Tips 1. Provide students with information about the four categories of public park lands.

City parks—all lands and water acquired by a city for park or recreational purposes.

County parks—any parkland managed by a county.

State parks—land preserved because of its natural beauty, historic interest, or other reason, and under the administration of a state.

National parks—tracts of land declared public property by a national government with a view toward preservation and development for purposes of recreation and culture.

Ask students to research a park in the area and tell what category it fits into and why. Alternatively, ask them to compare and contrast two of the park types: their purpose, where they are located, their intended use, their visitor numbers, or other pertinent information.

2. Ask students to conduct Internet research on the Chicago Wilderness, which was preserved as part of Burnham’s Plan of Chicago. Ask students, “What ecosystems are preserved?” Information can be found on the Chicago Wilderness site (www.chicagowilderness.org). This website contains information about the regional nature reserve in the Chicago area. There are descriptions of the prairies, woodlands, wetlands, and water that are protected as well as highlights of things to do and see.

3. Ask students to investigate land cover patterns in your state. There is a National Land Cover Dataset available online at landcover.usgs.gov as well as a World Data Center for Land Cover Data. The World Data Center system works to guarantee access to solar, geophysical, and related environmental data. The site can be accessed free of charge.

Ask students to compute the percentage of cover for each land cover class. Ask them these questions: What are the dominant land cover classes? Do residential and commercial developments cover a large percent of land in your state?

4. Use the following scenario to get students to think about land use patterns: A military base, situated near a small but rapidly growing city in your state, has been decommissioned and the land and buildings will be turned over to the county. The base land includes a lake, undisturbed wetlands that are a major resource for migratory birds, a large grassland, and forested hills. There are roads over 20% of the land, which includes housing for 2,000 families, plus schools, a hospital, offices, and many other buildings. A railroad spur comes into the main building area.

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Divide students into groups and have each group prepare a position paper on the best way to use the land. Some ideas might be to provide a medium-sized planned community, build a sports and recreation center, create a manufacturing hub, or make available only a few luxury homes in a gated community. Groups must present arguments for and against their proposal.

These can be presented to the class or turned in as a written assignment.

One way to do projects such as this is through the use of “jigsaw learning groups,” with each group consisting of four members. To establish the groups, have the students count off 1 through 4. Members numbered 1 from each group would then receive certain materials (maps, for instance, of land use and topography). Members numbered 2 would receive information of an economic nature—the county tax base and possible revenues from various proposed activities. Members numbered 3 would receive information regarding the impacts to the ecosystem of the various proposals. Members numbered 4 would receive information about the county infrastructure and needs— population increases and current levels of housing, jobs, schools, and businesses.

If class size and time permit, all the number 1 students would meet to discuss the maps and how to decipher them; the number 2 students would discuss the economics; and so on. Then each student would return to his or her group to share the information gained from the materials. This exercise promotes positive interdependence. The information provided could be made up to fit an imaginary scenario, or the students could be required to find information about an actual military base in your state and its associated city.

5. Each county in the country typically has a planning and zoning board. Encourage students to attend a meeting and take notes on what issues are discussed.

Determine if any of the issues involve additional plans for development, such as the annexation of unincorporated areas so that the land can be zoned for development. Have students report back to class and then examine through Geographic Information Systems (GIS) technologies, often available on the Web from each state’s department of natural resources, if any critical habitat or natural resources areas are under threat.

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Additional Resources Websites 1. New Census Data: Selective City Slowdowns and the City-Suburb Growth Gap, 2015, William H. Frey, The Brookings Institution, Washington, D.C. (www.brookings.edu/2015/05/21/new-census-data-selective-city-slowdownsand-the-city-suburb-growth-gap) This article provides contemporary information about the growth of the largest cities in the United States.

2. The National Park Service (www.nps.gov) This website has a wealth of information about the national parks managed by the NPS, including the nature, culture, history, and science of each park as well as online resources for educators.

3. Smart Growth Online, Smart Growth Network (www.smartgrowth.org) In 1996, the EPA joined with several nonprofit environmental groups and government agencies to form the Smart Growth Network. Their website provides basic information about smart growth and current projects undertaken across the country.

4. Sprawl & Growth Topics Covered in the Planning Commissioners Journal, Planning Commissioners Journal (www.plannersweb.com) This online journal contains many articles about city planning, including a number of articles on sprawl.

Audiovisual Materials 1. Toward a Livable City, 1991, distributed by Films for the Humanities and Sciences (www.films.com) This video follows the growth and development of Barcelona, Spain, as the city works to solve the problems of rapid growth after World War II. 2. Brazil: Urban Planning Challenges, 2009, part of a series called Sustainable Development: The World Challenge, distributed by Films for the Humanities and Sciences (www.films.com) This program explores innovative planning, engineering, and conservation at work in the Brazilian metropolis as it transcends many of the problems plaguing other South American cities.

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3. Reinventing the World: Cities, 2000, produced by Asterisk Productions, distributed by Bullfrog Films (www.bullfrogfilms.com) This program shows cities that have taken measures to become more sustainable: East Los Angeles; São Paolo and Curitiba, Brazil; Vancouver, British Columbia; and Portland, Oregon.

4. Subdivide and Conquer: A Modern Western, 1999, distributed by Bullfrog Films (www.bullfrogfilms.com) This 27-minute video, narrated by Dennis Weaver, describes how sprawl affects people and the environment, and shows ways to build more livable cities. A 56-minute version is also available.

Weighing the Issues What Made Your City?

Facts to consider: Many aspects of this question require an individual response. Prior to this question, the text discusses the geography of cities, so many answers may concentrate on the students’ geographical location (e.g., proximity to waterways, mountain passes, and the like) and how they may have funneled people and trade goods through. While economic advantages may have initially been responsible for a city’s growth, other considerations for modern times may be mentioned as well, such as a continued healthy and thriving economy, good municipal infrastructure, and a positive cultural atmosphere.

Environmental conditions, such as clean air and water as well as mild climate, are becoming more important as more of the population reaches an active retirement age.

Opinions will vary according to each student’s background, experience, and priorities.

Sprawl Near You Facts to consider: Many aspects of this question require an individual response.

The text offers some good indicators that may help students answer the questions for this issue. Some student answers may concentrate on these questions.

• Is public transportation available? If so, what kinds? How far is your house from shopping, work, school, etc.?

• How many vehicles are registered in your town or county? Has air quality decreased? If so, in what areas, and has the area affected spread in the past few years? How much traffic congestion is there? How much do people complain about the time spent in traffic?

• What kinds of jobs are available in your area?

• What is the price of housing, and where is housing least and most expensive? How much area is available for recreation?

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Opinions and ideas will vary according to each student’s background, experience, and priorities.

Your Urban Area Facts to consider: Many aspects of this question require an individual response.

Student answers should be based on opinions and their own views of what a livable neighborhood will look and feel like. Discussion may surround access to transportation, work, businesses, eating establishments, and cultural activities. Safety may also be an issue, with access to law enforcement, emergency services, and medical facilities. The availability of open space or urban parks may be important. Affordable, safe, and well-maintained housing close to all these venues may also be brought up in student answers.

The Science behind the Story How Do Baltimore and Phoenix Function as Ecosystems?

Observation: These two cities are very different: Baltimore is an Atlantic port city on Chesapeake Bay with a long history while Phoenix is a young and fastgrowing southwestern metropolis sprawling across the desert.

Question: What are the impacts of sprawling urbanization?

Study: Research teams in both cities combined old maps, aerial photos, and new remote sensing satellite data to reconstruct the history of landscape change. The study regions designated for each city encompass both heavily urbanized central city areas and rural and natural areas on the urban fringe.

Results: The study first determined that the fast flow of water, a result of development, through the watershed was causing environmental damage in Baltimore and worsening pollution. The study also determined that urbanization affects species and ecological communities, as cities and suburbs facilitate the spread of nonnative species (because people introduce exotic ornamental plants and because urbanization’s impacts on the soil, climate, and landscape favor weedy generalist species over more specialized native ones). Also, community ecologists studying the wild animals and plants that persist within Phoenix are finding that urbanization alters the relationships among them. In regard to social and demographic aspects, the researchers found that living closer to a park increases a home’s property value, and in Phoenix, environmental justice comes into play, as those neighborhoods exposed to industrial pollution are populated by the less affluent as well as by racial and ethnic minorities. In Baltimore, the reverse was witnessed, with toxic release sites in working-class white neighborhoods.

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Implications: Whether addressing the people, natural communities, or changing ecosystems of the urban environment, studies on urban ecology like those in Phoenix and Baltimore will be vitally informative in our ever-more-urban world.

Local Connections Consider the region where you live or attend school, including your nearest large city. For each of the following pursuits, describe what this area possesses, and suggest at least one way you think the area could enhance its quality of life and its sustainability: (a) planning and zoning policies; (b) walkable neighborhoods as promoted by smart growth and new urbanism; (c) transportation options (mass transit, bike lanes, ways to avoid car congestion); (d) parks, green spaces, and natural lands; and (e) green buildings.

Class time: Two class periods As a class, determine which city you will focus on. Then, break the class up into groups, with each group researching one of the aspects of the city listed above.

Give the students one class period to research their topic using the Internet. On the second day, have each group report the information they learned to the class. Be sure to leave at least 20 minutes at the end of class to discuss the city as a whole, including areas for improvement.

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Calculating Ecological Footprints Mode of transport

CO2 per person per mile

CO2 per person per year

CO2 emission reduction

Your estimated mileage per year

Your CO2 emissions per year

Automobile (driver only)

0.825 lbs

9,900 lbs

0

Answers will vary

Answers will vary

Automobile (2 persons)

0.413 lbs

4,956 lbs

4,950 lbs

Answers will vary

Answers will vary

Bus

0.261 lbs

3,132 lbs

6,768 lbs

Answers will vary

Answers will vary

Walking

0.082 lbs

984 lbs

8,916 lbs

Answers will vary

Answers will vary

Bicycle

0.049 lbs

588 lbs

9,312 lbs

Answers will vary

Answers will vary

Total = 12,000

Answers will vary

1. Bicycle travel gives the most miles per unit of carbon dioxide emitted.

2. Answers will vary.

3. Answers will vary. There are many ways we can all reduce our emissions, but with regard to transportation options, these include driving less, taking public transportation, walking and biking more, and driving in carpools when driving cars is necessary.

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14 Environmental Health and Toxicology Chapter Objectives This chapter will help students: Explain the goals of environmental health and identify major environmental health hazards Describe the types of toxic substances in the environment, the factors that affect their toxicity, and the defenses that organisms have against them Explain the movement of toxic substances and how they affect organisms and ecosystems Discuss the approaches used to study the effects of toxic chemicals on organisms Summarize risk assessment and risk management Compare philosophical approaches to risk and how they relate to regulatory policy

Lecture Outline I.

Central Case Study: Are We Being Poisoned by Our Food Packaging?

A. The beverage bottles, food cans, and wrappers that surround our food may pose a risk to our health by leaching harmful chemicals into the foods we eat and the liquids we drink.

B. Plastics are the predominant source of these hazardous chemicals. The chemical bisphenol A (BPA) and the class of chemicals called phthalates are of particular concern.

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C. BPA and phthalates leach out of their many products and into our food, water, air, and bodies. 90% of Americans carry detectable concentrations in their urine, according to the latest National Health and Nutrition Examination Survey conducted by the Centers for Disease Control and Prevention (CDC).

D. Hundreds of studies with rats, mice, and other animals have shown many apparent effects of BPA and phthalates, including a wide range of reproductive abnormalities.

E. Scientists say this is because BPA and phthalates mimic sex hormones, that is, they are structurally similar to sex hormones and can induce some of their effects in animals.

F. Some countries have banned BPA or limited its use in food packaging.

In the United States, its use in products for babies and small children has been restricted, but it continues to be used in other products.

G. In the face of mounting public concern about the safety of BPA, many companies are voluntarily choosing to remove it from their products.

II.

Environmental Health 1. Environmental health assesses environmental factors that influence our health and quality of life.

A. We face four types of environmental hazards.

1. Physical hazards arise from processes that occur naturally in our environment and pose risks to human life or health.

2. Chemical hazards include many of the synthetic chemicals that humanity manufactures, such as pharmaceuticals, disinfectants, and pesticides.

3. Biological hazards result from ecological interactions among organisms. When we become sick from a virus, bacterial infection, or other pathogen, we are suffering parasitism. This is what we call infectious disease. a. Some infectious diseases are spread when pathogenic microbes attack us directly. b. With others, infection occurs through a vector, an organism (such as a mosquito) that transfers the pathogen to the host.

4. Hazards that result from our place of residence, the circumstances of our socioeconomic status, our occupation, or our behavioral choices can be thought of as cultural hazards.

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B. Toxicology is the study of chemical hazards.

1. Toxicology is the science that examines the effects of poisonous substances on humans and other organisms. a. Toxicologists assess and compare substances to determine their toxicity, the degree of harm a chemical substance can inflict. b. A toxic substance or poison is called a toxicant, but any chemical substance may exert negative impacts if we ingest or expose ourselves to enough of it.

2. Environmental toxicology deals specifically with toxic substances that come from or are discharged into the environment.

C. The biological hazard of infectious disease continues to plague humanity.

1. Infectious diseases spread when a pathogenic organism enters a host through the skin, via the respiratory system, or by the consumption of contaminated food or water.

2. Infectious diseases account for about 17% of deaths worldwide each year but can be responsible for up to 50% of annual deaths in some poorer nations.

D. We fight infectious disease with diverse approaches.

1. These include sterilizing drinking water; providing sanitary facilities (such as indoor plumbing or communal latrines), which prevent fecal contamination of drinking water sources; ensuring nutritious diets for all people to strengthen the immune system; and providing medical care that identifies infected individuals and breaks the cycle of infection through treatment, quarantining, and early intervention.

2. Another important tool in fighting infectious disease is expanding access to health care.

3. Education campaigns play a vital role in rich and poor nations alike.

E. Noninfectious disease is affected by genes, environment, and lifestyle.

1. Noninfectious diseases, such as cancer and heart disease, develop without the action of a foreign organism.

2. More than half the world’s deaths result from noninfectious diseases, but the incidence of such diseases can be lessened by wider adoption of healthy lifestyles.

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F. Many cultural hazards exist indoors.

1. Modern Americans spend roughly 90% of their lives indoors.

2. Cigarette smoke and radon are leading indoor hazards and are the top two causes of lung cancer in developed nations. a. Radon is a highly toxic radioactive gas that is colorless and undetectable without specialized kits.

3. Homes and offices can have problems with toxic compounds produced by mold, which can flourish in wall spaces when moisture levels are high. a. Asbestos, used in the past as insulation in walls and other products, is dangerous when inhaled. b. Long-term exposure to asbestos scars the lung tissue, impairs lung function, and leads to a disorder called asbestosis.

4. Lead poisoning is another indoor health hazard. Lead is a heavy metal and, when ingested, can cause damage to the brain, liver, kidneys, and stomach; learning problems and behavioral abnormalities in children; anemia; hearing loss; and even death. a. Lead poisoning captured headlines recently when officials in Flint, Michigan (MI), switched the city’s water supply from the city of Detroit to the Flint River. The new water was not treated to prevent corrosion of lead pipes and residents in Flint were exposed to concentrations of lead in their water up to 1000 times higher than the allowable limit set by the EPA. 5. One recently recognized hazard is a group of chemicals known as polybrominated diphenyl ethers (PBDEs). These chemicals persist and accumulate in living tissue, and their abundance in the environment and in people in the United States is doubling every few years.

G. Risks must be balanced against rewards.

III.

Toxic Substances and Their Effects on Organisms 1. Our environment contains countless natural substances that may pose health risks. These include toxins, toxic chemicals manufactured in the tissues of living organisms. In addition, we are exposed to many synthetic (artificial, or human-made) chemicals, some of which also have toxic properties.

A. Synthetic chemicals are all around us—and in us.

B. Silent Spring began the public debate over synthetic chemicals.

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1. Rachel Carson brought together a diverse collection of scientific studies, medical case histories, and other data to demonstrate that the insecticide DDT in particular, and artificial pesticides in general, are hazardous to people, wildlife, and ecosystems.

2. Carson’s book was a bestseller and helped generate significant social change in views and actions toward the environment.

3. Despite its damaging effects, DDT is still manufactured today because some developing countries with tropical climates use it to control disease vectors, such as mosquitoes that transmit malaria. In these countries, malaria represents a greater health threat than the toxic effects of the pesticide.

C. Not all toxic substances are synthetic.

1. Toxic substances exist naturally in the environment around us and in the foods we eat. Scientists are actively debating just how much risk natural toxicants pose.

D. Toxic substances come in different types.

1. Carcinogens are substances or types of radiation that cause cancer.

2. Mutagens are substances that cause genetic mutations in the DNA of organisms.

3. Chemicals that cause harm to the unborn are called teratogens.

4. Neurotoxins assault the nervous system.

5. Allergens overactivate the immune system, causing an immune response when one is not necessary.

6. Pathway inhibitors are toxicants that interrupt vital biochemical processes in organisms by blocking one or more steps in important biochemical pathways.

7. Most recently, scientists have recognized endocrine disruptors, toxicants that interfere with the endocrine system.

8. Many plastic products also contain another class of hormonedisrupting chemicals called phthalates. Health research on phthalates has linked them to birth defects, breast cancer, reduced sperm counts, and other reproductive effects.

E. Organisms have natural defenses against toxic substances.

1. Skin, scales, and feathers are the first line of defense against toxic substances because they resist uptake from the surrounding environment.

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2. Organisms possess biochemical pathways that use enzymes to detoxify harmful chemicals.

3. Some toxic substances cannot be effectively detoxified or made water-soluble by detoxification enzymes.

F. Individuals vary in their responses to hazards.

G. The type of exposure can affect the response.

1. The risk posed by a hazard often varies according to whether a person experiences high exposure for short periods of time, known as acute exposure, or low exposure over long periods of time, known as chronic exposure. Acute exposure is easier to recognize, but chronic exposure is more common and is more difficult to detect and diagnose.

IV.

Toxic Substances and Their Effects on Ecosystems A. Airborne substances can travel widely.

1. Toxic substances are released around the world from agricultural, industrial, and domestic activities and may sometimes be redistributed by air currents, exerting impacts on ecosystems far from their site of release.

2. Because so many substances are carried by the wind, synthetic chemicals are ubiquitous worldwide—even in seemingly pristine areas.

3. Effects can also occur over relatively shorter distances.

B. Toxic substances may concentrate in water.

1. Water running off from land often transports toxicants from large areas and concentrates them in small volumes of surface water.

2. Many chemicals are soluble in water and enter organisms’ tissues through drinking or absorption.

C. Some toxicants persist in the environment.

1. A toxic substance that is released into the environment may degrade quickly and become harmless, or it may remain unaltered and persist for many months, years, or decades.

2. Persistent synthetic chemicals exist in our environment today because we have designed them to persist. Sooner or later, however, most toxicants degrade into simpler compounds called breakdown products.

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D. Toxic substances may accumulate and move up the food chain.

1. Within an organism’s body, some toxic substances are quickly excreted, and some are degraded into harmless breakdown products. Others persist intact in the body. a. Persistent toxicants accumulate in an animal’s body in a process termed bioaccumulation, such that the animal’s tissues have a greater concentration of the substance than exists in the surrounding environment.

2. Toxic substances that bioaccumulate in an organism’s tissues may be transferred to other organisms as predators consume prey, resulting in a process called biomagnification.

E. Toxic substances can threaten ecosystem services.

V.

Studying the Effects of Hazards A. Wildlife studies integrate work in the field and the lab.

1. Scientists study the impacts of environmental hazards on wild animals to help conserve animal populations and also to understand potential risks to people.

2. Often, wildlife toxicologists work in the field with animals to take measurements, document patterns, and generate hypotheses, before heading to the laboratory to run controlled manipulative experiments to test their hypotheses.

B. Human studies rely on case histories, epidemiology, and animal testing.

1. In studies of human health, we gain much knowledge by directly studying sickened individuals. This process of observation and analysis of individual patients is known as a case history approach.

2. Epidemiological studies involve large-scale comparisons among groups of people, usually contrasting a group known to have been exposed to some hazard and a group that has not.

3. The epidemiological process is akin to a natural experiment in which the experimenter studies groups of research participants made available by some event that has occurred.

4. To establish causation, manipulative experiments are needed.

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C. Dose-response analysis is a mainstay of toxicology.

1. The standard method of testing with lab animals in toxicology is dose-response analysis. a. The dose is the amount of substance the test animal receives, and the response is the type or magnitude of negative effects the animal exhibits as a result. b. The data are plotted on a graph, with the dose on the x-axis and the response on the y-axis. The resulting curve is called a dose-response curve.

2. Once they have plotted a dose-response curve, toxicologists can calculate a convenient shorthand gauge of a substance’s toxicity: the amount of the substance it takes to kill half the population of study animals used. This lethal dose for 50% of individuals is termed the LD50. A high LD50 indicates low toxicity, and a low LD50 indicates high toxicity.

3. Nonlethal health effects are determined by the level of toxicant at which 50% of the population is affected (ED50).

4. Some substances can elicit effects at any concentration, but for others, responses may occur only above a certain dose, or threshold.

Such a threshold dose might be expected if the body’s organs can fully metabolize or excrete a toxicant at low doses but become overwhelmed at high concentrations.

5. Sometimes a response may decrease as a dose increases.

6. Researchers generally give lab animals much higher doses relative to body mass than people would receive in the environment.

D. Chemical mixes may be more than the sum of their parts.

1. Interactive impacts that are greater than the simple sum of their constituent effects are called synergistic effects.

2. Traditionally, environmental health has tackled the effects of single hazards one at a time, and single-substance tests have received priority. This is changing, but the interactive effects of most chemicals are unknown.

E. Endocrine disruption poses challenges for toxicology.

1. Because so many novel synthetic chemicals exist in very low concentrations over wide areas, many scientists suspect that we may have underestimated the dangers of compounds that exert impacts at low concentrations.

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2. The idea that synthetic chemicals might be altering the hormones of animals was not widely appreciated until the 1996 publication of the book Our Stolen Future, by Theo Colburn, Dianne Dumanoski, and J.P. Myers.

3. Today, thousands of studies have linked hundreds of substances to effects on reproduction, development, immune function, brain and nervous system function, and other hormone-driven processes.

4. Much of the research into hormone disruption has brought about strident debate.

F. Are synthetic chemicals underappreciated as agents of global change?

1. In recent decades, the growth in the diversity of application of synthetic chemicals has grown, but our research into their effects is lacking.

VI.

Risk Assessment and Risk Management A. We express risk in terms of probability.

1. Risk can be measured in terms of probability, a quantitative description of the likelihood of a certain outcome. The probability that some harmful outcome (for instance, injury, death, environmental damage, or economic loss) will result from a given action, event, or substance expresses the risk posed by that phenomenon.

B. Our perception of risk may not match reality.

C. Risk assessment analyzes risk quantitatively.

1. The quantitative measurement of risk and the comparison of risks involved in different activities or substances together are termed risk assessment.

2. Assessing risk for a chemical substance involves several steps.

D. Risk management combines science and other social factors.

1. Accurate risk assessment is a vital step toward effective risk management, which consists of decisions and strategies to minimize risk.

2. In environmental health and toxicology, comparing costs and benefits can be difficult because the benefits are often economic, whereas the costs often pertain to health.

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VII.

Philosophical and Policy Approaches 1. There are two basic philosophical approaches to categorizing substances as safe or dangerous. a. One approach is to assume that substances are harmless until shown to be harmful—the “innocent until proven guilty” approach. b. The other approach is to assume that substances are harmful until shown to be harmless. This approach follows the precautionary principle.

A. Philosophical approaches are reflected in policy.

1. This choice of philosophical approach has direct implications for policy, and nations vary in how they blend the two approaches when it comes to regulating synthetic substances.

B. The EPA regulates industrial chemicals.

1. The Toxic Substances Control Act (TSCA) directs the EPA to monitor thousands of industrial chemicals manufactured in or imported into the United States.

2. Because the registration process takes economic considerations into account, critics say it allows hazardous chemicals to be approved if the economic benefits are judged to outweigh the hazards.

3. The Frank R. Lautenberg Chemical Safety for the 21st Century Act was passed in 2016. The act improves upon the TSCA by directing the EPA to review the potential toxicity of all industrial chemicals currently in use and by subjecting new chemicals to rigorous safety testing before they are used in products.

C. Toxicants are regulated internationally.

1. In 2007, the European Union’s REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals) program went into effect. The burden of proof for chemical safety shifted from governments to industries.

2. The world’s nations have also sought to address chemical pollution with international treaties.

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Key Terms acute exposure allergens asbestos asbestosis bioaccumulation biological hazards biomagnification breakdown products carcinogens case history chemical hazards chronic exposure cultural hazards dose response dose-response analysis dose-response curve ED50 endocrine disruptors environmental health environmental toxicology epidemiological studies infectious disease LD50 lead

lead poisoning mutagens neurotoxins noninfectious disease pathway inhibitors phthalates physical hazards polybrominated diphenyl ethers (PBDEs) probability radon REACH risk risk assessment risk management synergistic effects teratogens threshold dose Toxic Substances Control Act toxicant toxicity toxicology toxins vectors

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Teaching Tips 1. Assign students to read selections from Our Stolen Future (Colburn, Dumanoski, and Myers, Dutton Publishing, 1996) and/or Silent Spring (Rachel Carson, 1962). There is a website that accompanies Our Stolen Future at www.ourstolenfuture.com, which provides links to current research on the effects of endocrine disruptors. The Online Ethics Center for Engineering and Science at Case Western Reserve University (onlineethics.org) provides information about Rachel Carson and a summary of her book.

2. Certain facilities in the United States are required to report their releases of toxic substances to the state and the EPA. These data are reported in the Toxic Releases Inventory (TRI) Public Data Release Report, and are made available to the public via the Internet. Ask students to find information about toxic releases in their neighborhoods by accessing the TRI Explorer at www.epa.gov/triexplorer. The TRI Explorer is a searchable online database that lets users quickly get information about releases and transfers of toxic chemicals. Have your students check their ZIP code or their county, or have each group choose a county near you.

3. An issue that has generated a good deal of controversy is contaminants in children’s candy. In April 2004, the Orange County Register conducted an investigation and published a six-part story about lead in candy, imported mostly from Mexico. The story includes a number of candies that you might not think are imported, and some candies that are manufactured in the United States by major companies. The story, sidebars, and news reports since the initial story are all available at the newspaper’s website (www.ocregister.com) and include coverage of environmental contaminants, local and international laws and regulations, risk assessment, and the pitting of manufacturers against health officials. Divide your students into groups and have each group take one aspect of the story.

• How lead gets into candy • Allowable levels of lead • Effects of lead in the body (in children, in adults, and during pregnancy) • Current estimates of numbers of people affected • Treatments for lead poisoning • Regulations on lead in Mexico and their enforcement • Regulations on lead in the United States and their enforcement • What some states and cities are doing • What is being done in your area

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4. Have each group make a poster or PowerPoint presentation on a specific category of contaminant to show the class. Hang the posters or PowerPoint printouts in school hallways, place them on a class website, or give a public presentation of the information.

5. It’s approaching the middle of the semester and you are thinking of giving a midterm exam, or at least a midterm grade so that students know where they stand. What about having students give the course some midterm feedback as well? The website for the Office of Educational Development at the University of California–Berkeley (teaching.berkeley.edu/news/because-squeaky-wheelshould-not-always-get-grease-different-way-conduct-mid-semester) has a link to a Standard Midsemester Evaluation form and a second link to Responding to Midsemester Evaluations.

The students spend five minutes in class writing an anonymous evaluation of the course and their progress, which can help you fine-tune your planning for the rest of the semester. The second evaluation form includes tips on dividing student responses into things you might change this semester, things you might change in future semesters, and things that either are structural or that you cannot change.

Additional Resources Websites 1. EXTOXNET, a cooperative effort of the University of California–Davis, Oregon State University, Michigan State University, Cornell University, and the University of Idaho (extoxnet.orst.edu) This website provides information for the public about pesticides, including pesticide information profiles (PIPs), toxicology information briefs (TIBs), and toxicology issues of concern (TICs).

2. Indoor Air Quality, US Environmental Protection Agency (www.epa.gov/indoor-air-quality-iaq) This resource provides information about indoor air pollutants, their potential effects, and ways to minimize pollutant concentrations.

3. Report on Carcinogens, 2016, US Department of Health and Human Services, Public Health Service, National Toxicology Program (ntp.niehs.nih.gov/whatwestudy/assessments/cancer/roc/index.html?utm_ source=direct&utm_medium=prod&utm_campaign=ntpgolinks&utm_term=ro c14) This report is an informational scientific and public health document that identifies and discusses substances that may pose a carcinogenic hazard to human health.

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4. Toxicology Tutor, National Library of Medicine, National Institutes of Health (toxtutor.nlm.nih.gov/) This online tutorial introduces the basics of toxicology written at the introductory college level.

5. Environmental Working Group (EWG) (ewg.org) Public interest research and information center on health and toxicology, personal care products and their effects, and on the impact of farm bill legislation vis-á-vis agricultural chemicals and public health.

6. Science and Environmental Health Network (sehn.org) The website contains information about the “Precautionary Principle” and other topics related to human health issues and the presence of environmental toxins.

7. Agency for Toxic Substances and Disease Registry, Centers for Disease Control, US Department of Health and Human Services (www.atsdr.cdc.gov) This website contains summaries of various toxic materials in documents called ToxFAQs.

Audiovisual Materials 1. Drumbeat for Mother Earth, 2002, video produced by the Indigenous Environmental Network and Greenpeace and distributed by Bullfrog Films (www.bullfrogfilms.com) This video describes how toxic chemicals are the greatest threat to the survival of indigenous peoples.

2. Bhopal: The Second Tragedy, 1995, video distributed by Films for the Humanities & Sciences (www.films.com) This video program describes the Union Carbide methyl isocyanate disaster outside Bhopal, India, in 1984 and details its protracted consequences.

3. American Experience: Rachel Carson & Silent Spring, 2010, Public Broadcasting Service (www.pbs.org/wgbh/americanexperience/films/rachelcarson/) This video provides a contemporary reflection on Carson’s pivotal book, Silent Spring.

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Weighing the Issues A Circle of Poison?

Facts to consider: This question requires an individual response. The selling of DDT to other countries does not lessen the harmful effects of the pesticide. Perhaps products should not be exported if they are banned domestically. Synthetic chemicals can travel great distances in the environment—far from their place of application—so exporting these chemicals to one country may cause harmful effects in other countries that did not agree to their use. However, other countries might have different priorities. In a developing country, DDT may be the pesticide of choice because it is effective and inexpensive, maximizing needed income. Tropical countries may deem the problem for which they will use the chemical (malaria or the Zika virus, for example) greater than the effects of the chemical on humans or the rest of the ecosystems. However, because pesticide sales are permitted from the United States to other countries, all available information the United States has about the negative effects of such substances, and how to minimize those effects, should be disseminated publicly in the countries to which these substances are sold.

How Much Safety Testing Should Chemicals Undergo?

Facts to consider: Responses may vary about whether proof of safety should be required and whether manufacturers should bear the burden of this proof. Many students may argue that if substances are permitted to go to market without proof of safety, some dangerous chemicals may do great harm before their effects are discovered. Others will argue that the cost of these chemicals will increase due to the additional research needed prior to their commercial release. Some students may point out that the public can’t access the research that is being done by chemical manufacturers, as has been the case with nicotine research done by some of the major US tobacco companies. Adopting the precautionary principle would certainly reduce the number of chemicals on the market. In the long run, manufacturers might develop new chemicals that have fewer toxic effects or consumers may buy more of the chemicals that remain available, reducing or eliminating the loss of revenue to manufacturers.

The Science behind the Story Are Endocrine Disruptors Lurking in Your Fast Food?

Question: Do people who have recently eaten fast food have higher levels of BPA and phthalates in their bodies than people who have not recently eaten fast food?

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Study: Dr. Ami Zota and her team from George Washington University used the National Health and Nutrition Examination Survey (NHANES) to investigate this question. The NHANES survey is conducted every two years by the Centers for Disease Control and Prevention (CDC) and collects information from people across the United States by asking participants to undergo a physical examination by a medical professional, providing blood and urine samples, and completing a detailed questionnaire about their lifestyle, including a description of the foods they have recently consumed. Dr. Zota used this data to look for relationships in the subjects’ reported consumption of fast food and their urinary concentrations for BPA and two types of phthalates used in food packaging and processing: di(2ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DiNP).

Results: Dr. Zota’s team found a positive correlation between the consumption of fast food and urinary concentrations of both types of phthalates. The quantity of fast food eaten was also related to concentrations of the two phthalates in subjects.

People who consumed less than 35% of their calories from fast food (“low consumers”) had DEHP levels 15% higher than people who had not eaten fast food (“nonconsumers”), while those who consumed more than 35% of their calories from fast food (“high consumers”) had DEHP levels 23% higher than people who had not eaten fast food. Similar results were observed for DiNP, where low consumers and high consumers had urinary concentrations 24% and 39% higher, respectively, than nonconsumers. Unlike phthalates, BPA did not show a statistically significant correlation with fast-food consumption.

What Role Do Pesticides Play in the Collapse of Bee Colonies?

Question: How do the multitude of pesticides in the environment affect honeybee colonies?

Experiment: Dr. Dennis vanEngelsdorp and his team from the University of Maryland surveyed 91 bee colonies from March 2007 to January 2008. Pesticides can become concentrated in beehives because bees forage over a wide area for pollen, some of which may contain pesticides. To assess the colony’s cumulative pesticide exposure, the researchers collected samples of beebread (a pollen-rich substance consumed by bees) throughout the season, and took samples of honeycomb wax (in which larvae were brooded and honey and beebread were stored) at the beginning and end of the season. The samples were then sent to a laboratory and screened for the presence of 171 common agricultural pesticides.

At the end of the season, the researchers noted which hives survived the entire season, as well as those that experienced a “queen event”—the death of the queen bee. As the number of queen events increases in a hive, so does the likelihood of the hive dying. For each of the samples collected, the researchers determined the 228 ..

total number of pesticides detected, the number of those pesticides that exceeded accepted toxicity levels, and the colony’s hazard quotient (HQ), a measure of the cumulative toxicity the hive experienced from all the detected pesticides.

Results: In all, 93 different pesticides were detected in the colonies over the course of the season. More than half of the bee colonies perished during the study period, with hive mortality rates increasing as the season progressed. Correlation analysis revealed that the likelihood of a colony dying was positively correlated with the total number of pesticides in beebread and honeycomb wax but not with the concentration of the pesticides, as measured by HQ. Hives experiencing a queen event contained more total pesticides in their beebread and wax and had a higher HQ in wax than hives that maintained their queen throughout the season.

Local Connections As shown in a SCIENCE BEHIND THE STORY feature in the chapter, the consumption of fast food can lead to elevated exposure to phthalates. It follows that states that have the most fast-food locations per capita may have higher percapita exposure to phthalates. How does your state stack up versus others when it comes to fast food? How do the various regions of the United States compare in the number of fast-food restaurants per capita?

Class time: This activity could be completed during class or as a homework assignment.

Direct students to Datafiniti (datafiniti.co/fast-food-restaurants-america/) to read their report Ranking Cities With the Most and Least Fast Food Restaurants. The list compiled on this website includes some types of fast food restaurants that were not included in the study discussed in the SCIENCE BEHIND THE STORY feature in the chapter, but it is a great place to start. Students may also find additional information by doing an Internet search of their own.

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Calculating Ecological Footprints Consumer

Pesticide active ingredients (lb)

United States

1.18 billion

World (total)

5.82 billion

Your share of U.S. total

3.76

Your share of world total

1.21

1. See table above. Answers will vary.

2. Ecological footprint ratio of US/world: 3.76 lbs per capita/1.21 lbs per capita = 2.96. Pesticide use in the United States is about three times higher than global pesticide use. Answers will vary, but students should take into consideration that the aggregate use data do not tell you which pesticides are being used, where they are being used, what their fate in the environment is (Are they persistent? Are they bioaccumulated? Are they mobile?), what the likelihood of exposure is, nor what the toxicity is to humans. These are important factors in realistically assessing the risk posed by those few pounds of pesticides used per person, per year.

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15 Freshwater Systems and Resources Chapter Objectives This chapter will help students: Describe the distribution of fresh water on Earth and the major types of freshwater systems Discuss how humans use water and alter fresh water systems Assess problems of water supply and propose solutions to address the depletion of fresh water Describe the major classes of water pollution and propose solutions to address water pollution Explain how we treat drinking water and wastewater

Lecture Outline I.

Central Case Study: Reaching the Tipping Point: Fracking and Fresh Water in West Texas A. Conflicts over water are common in the American West, where water is scarce. These conflicts are likely to get worse as climate change leads to more long-term droughts.

B. Many Western communities are also situated in areas with extensive crude oil and natural gas “unconventional” fossil fuel reserves. In these reserves, petroleum (shale oil) and natural gas (shale gas) are locked up within non-porous shale, but can be freed through the process of hydraulic fracturing (fracking).

C. Hydraulic fracturing involves drilling deep into the Earth and then angling the drill horizontally once a shale formation is reached. An electric charge sets off targeted explosions that perforate the drilling 231 ..

pipe and create fractures in the shale. Drillers then pump a slurry of water, sand, and chemicals down the pipe under great pressure. The sand lodges in the fractures and holds them open, while some of the liquids return to the surface as wastewater. Oil and natural gas trapped in the shale migrate into the fractures and are carried through the drilling pipe to the surface, where they are collected in tanks.

D. Fracking requires a great deal of water and many of the formations are in areas that are already experiencing water stress.

E. Three-fourths of the fracking wells drilled in the United States from 2011–2014 were in water-scarce areas and more than half were in areas suffering from drought.

F. The fracking industry is working to develop new techniques for fracking that require less water or use briny groundwater that is unsuitable for other uses.

II.

Freshwater Systems 1. Of all the water on Earth, only 2.5% is considered fresh water, water that is relatively pure with few dissolved salts. Most of that is tied up in glaciers, ice caps, and underground aquifers.

2. Water is renewed and recycled as it moves through the water cycle.

A. Groundwater plays key roles in the hydrologic cycle.

1. Surface water is water located atop Earth’s surface and groundwater is water beneath the surface that resides within pores in soil or rock.

2. Groundwater is contained within aquifers: porous, spongelike formations of rock, sand, or gravel that can hold water. An aquifer’s upper layer contains pore spaces partly filled with water.

In the lower layer, the spaces are completely filled with water. The boundary between these two zones is the water table. Any area where water infiltrates Earth’s surface and reaches an aquifer below is known as a recharge zone.

3. When a porous, water-bearing layer of rock, sand, or gravel is trapped between upper and lower layers of less permeable substrate (often clay), we have a confined aquifer, or artesian aquifer. In such a situation, the water is under great pressure. In contrast, an unconfined aquifer has no impermeable upper layer to confine it, so its water is under less pressure and can be readily recharged by surface water.

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B. Surface water converges in river and stream ecosystems.

1. Water that falls from the sky as rain, emerges from springs, or melts from snow or a glacier and then flows over the land surface is called runoff. The area of land drained by a river system—a river and all its tributaries—is that river’s watershed, also called a drainage basin.

2. Landscapes determine where rivers flow, but rivers shape the landscapes through which they run.

3. Areas nearest a river’s course that are flooded periodically are said to be within the river’s floodplain.

4. Rivers and streams host diverse ecological communities.

C. Lakes and ponds are ecologically diverse systems.

1. Lakes and ponds are bodies of standing surface water.

2. There are four zones in lakes or ponds. a. The region ringing the edge of a water body is the littoral zone. b. The bottom of a lake or pond is the benthic zone. c. The shallow waters away from shore are termed the limnetic zone, where light enters and supports phytoplankton, which in turn support zooplankton. d. Deeper in open water, where the sunlight does not reach, is the profundal zone, which lacks plant life.

3. Ponds and lakes change over time as streams and runoff bring them sediment and nutrients. Oligotrophic lakes and ponds, which are low in nutrients and high in oxygen, may slowly transition to the high-nutrient, low-oxygen conditions of eutrophic water bodies.

D. Freshwater wetlands include marshes, swamps, bogs, and vernal pools.

1. Wetlands are systems in which the soil is saturated with water and which generally feature shallow standing water with ample vegetation.

2. Some wetlands are seasonal, being wet only at some times of the year.

3. Wetlands are extremely valuable habitats for wildlife and also provide important ecosystem services.

4. Despite the vital roles played by wetlands, people have drained and filled them, especially for agriculture.

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5. Wetlands and other aquatic systems are affected by people when they modify the flow of rivers and introduce pollutants that alter water’s chemical, biological, and physical properties.

III.

Human activities affect waterways A. Fresh water and human populations are unevenly distributed across Earth.

B. Water supplies households, industry, and agriculture.

1. Globally, we allot about 70% of our annual fresh water to agriculture. Industry accounts for roughly 20%, and residential and municipal uses for only 10%.

2. When we remove water from an aquifer or surface water body and do not return it, this is called consumptive use. In contrast, nonconsumptive use of water does not remove, or only temporarily removes, water from an aquifer or surface water body.

C. Excessive water withdrawals can drain rivers and lakes.

D. Groundwater can also be depleted.

1. Groundwater is more easily depleted than surface water because most aquifers recharge very slowly.

2. As aquifers are mined, water tables drop.

3. When groundwater is overextracted in coastal areas, salt water from the ocean can intrude into inland aquifers, making well water undrinkable.

4. Sometimes land subsides suddenly, creating sinkholes, areas where the ground gives way with little warning, occasionally swallowing homes and businesses.

E. Groundwater supplies our bottled water.

1. Bottled water also exerts substantial ecological impact.

2. Roughly three of four plastic water bottles are not recycled after use in the United States, generating close to 1.5 million tons of plastic waste annually.

F. People build levees along rivers to control floods.

1. Flooding is a normal, natural process that occurs when snowmelt or heavy rain swells the volume of water in a river so that water spills over the river’s banks.

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2. To protect against floods, communities and governments have built levees (also called dikes) along banks of rivers to hold water in main channels.

G. We divert surface water to suit our needs.

H. Most of Earth’s major rivers are dammed.

1. A dam is any obstruction placed in a river or stream to block its flow. Dams create reservoirs, artificial lakes that store water for human use.

I. Some dams are being removed.

1. By removing dams and letting rivers flow free, we can restore riparian ecosystems, reestablish economically valuable fisheries, and revive river recreation.

IV.

Solutions to Depletion of Fresh Water A. Increasing water supplies for humans carries ecological costs.

1. Constructing large dams was a common solution to water shortages in the past. However, large dams have already been placed at nearly all sites suitable for them. Therefore, building dams is not a viable solution.

2. A supply strategy with some potential for sustainability is to generate fresh water by desalination, or desalinization, the removal of salt from seawater or other water of marginal quality. a. One method of desalination mimics the hydrologic cycle by heating and evaporating ocean water and then condensing the vapor—essentially distilling fresh water. b. Another method forces water through membranes with tiny pores to filter out salts; the most common such process is reverse osmosis.

3. Desalination is expensive, requires large inputs of fossil fuel energy, kills aquatic life at water intakes, and generates concentrated salty waste.

B. We can decrease our demand for water by using it more efficiently.

1. Agricultural demand can be reduced. a. Farmers can improve efficiency by lining irrigation canals to prevent leaks, leveling fields to minimize runoff, and adopting efficient irrigation methods. b. Choosing crops to match the land and climate in which they are farmed can also save huge amounts of water.

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c. Selective breeding and genetic modification can create crop varieties that produce high yields with less water.

2. We can lower residential and industrial water use. a. Xeriscaping, landscaping using plants adapted to arid conditions, has become increasingly popular in the US Southwest.

3. Industry and municipalities can take water-saving steps as well. a. Industries are shifting to processes that use less water. b. Some municipalities are adopting water-saving measures, including Las Vegas, which is recycling treated municipal wastewater for irrigation and industrial uses.

C. Market-based approaches to water conservation are being debated.

1. Economists who want to use market-based strategies to achieve sustainable water use have suggested ending government subsidies of inefficient practices and instead letting water become a commodity whose price reflects the true costs of its extraction. a. Others worry that making water a fully priced commodity would make it less available to the world’s poor and increase income disparity. b. Because the industrial use of water can be 70 times more profitable than agricultural use, market forces alone might favor uses that would benefit wealthy and industrialized people, companies, and nations at the expense of the rural poor.

2. The privatization of water supplies has been tried in hopes of increasing efficiency, but many people worry that firms have little incentive to allow equitable access to water for rich and poor alike.

3. Decentralization of control over water, from the national level to the local level, can help conserve water.

4. Regardless of how demand is addressed, the shift from supply-side to demand-side solutions is paying dividends.

D. Nations often cooperate to resolve water disputes.

V.

Fresh Water Pollution and Its Control A. Water pollution comes from point sources and nonpoint sources.

1. Water pollution—changes in the chemical, physical, or biological properties of waters caused by human activities—comes in many forms and can have diverse impacts on aquatic ecosystems and human health.

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2. Some water pollution is emitted from point sources—discrete locations such as a factory or sewer pipe. In contrast, pollution from nonpoint sources is cumulative, arising from multiple inputs over larger areas such as farms, city streets, and residential neighborhoods.

B. Water pollution takes many forms.

1. Toxic and endocrine-disrupting chemicals a. Our waterways are polluted with many toxic substances including pesticides, industrial chemicals, petroleum products, fracking fluids, heavy metals, and radioactive substances. b. Endocrine disruptors—chemicals that mimic the hormones that regulate physiology and stimulate growth, development, and sexual maturity—are of particular concern.

2. Pathogens and waterborne diseases a. Disease-causing organisms (pathogenic viruses, protists, and bacteria) can enter drinking water supplies that become contaminated with human waste from inadequately treated sewage or with animal waste from feedlots, chicken farms, or hog farms. b. Biological pollution by pathogens causes more human health problems than any other type of water pollution. c. We reduce the risks posed by waterborne pathogens by using chemicals or other means to disinfect drinking water and by treating wastewater to prevent fecal contamination of waterways.

3. Nutrient pollution a. When excess nitrogen and/or phosphorus enters a water body, it fertilizes algae and aquatic plants, boosting their growth. As the crowded algae die off and settle on the bottom, bacteria consume them. Because this decomposition requires oxygen, dissolved oxygen levels in the water decline. These levels can drop too low to support fish and shellfish, leading to hypoxic conditions and dead zones.

4. Biodegradable wastes a. Wastewater is water affected by human activities and can be a source of biodegradable wastes.

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5. Sediment a. Eroded soils, called sediments, can be carried to rivers by runoff and transported long distances by river currents.

6. Plastic debris a. Surface water and groundwater can be contaminated with small pieces of plastic, called microplastics. Microplastics form when discarded plastics in the environment are broken down by factors such as heat or ultraviolet light. Microplastics can also come from microbeads, small pieces of plastic that are added to some cosmetics, soaps, and toothpastes.

7. Thermal pollution a. Water’s ability to hold dissolved oxygen decreases as temperature rises, so some aquatic organisms may not survive when human activities raise water temperatures. b. When dam operators release water from the depths of a reservoir, downstream water temperatures drop suddenly due to the influx of cold water. In some river systems, these pulses of cold water have favored cold-loving invasive fish species over native species adapted to normal river temperatures.

C. Groundwater pollution is a significant problem.

1. Some chemicals that are toxic at high concentrations, including aluminum, fluoride, nitrates, and sulfates, occur naturally in groundwater.

2. Industrial, agricultural, and urban wastes—from heavy metals to petroleum products to solvents to pesticides—can leach through soil and seep into aquifers. Pathogens and other pollutants can also enter groundwater through improperly designed wells and from the pumping of liquid hazardous waste below ground.

3. The leakage of carcinogenic pollutants (such as chlorinated solvents and gasoline) from underground tanks of oil as well as industrial chemicals also poses a threat to groundwater.

4. The leaking of radioactive compounds from underground tanks is also a source of groundwater pollution.

5. Agriculture contributes to groundwater pollution in several ways. a. Pesticides b. Nitrate from fertilizers D. Legislative and regulatory efforts have helped to reduce pollution.

E. We treat our drinking water.

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F. We treat our wastewater.

1. Wastewater includes water that carries sewage; water from showers, sinks, washing machines, and dishwashers; water used in manufacturing or industrial cleaning processes; and storm water runoff.

2. In rural areas, septic systems are the most popular method of wastewater disposal. In a septic system, wastewater runs from the house to an underground septic tank, inside which solids and oils separate from water. The clarified water proceeds downhill to a drain field of perforated pipes laid horizontally in gravel-filled trenches underground. Microbes decompose pollutants in the wastewater these pipes emit. Periodically, solid waste from the septic tank is pumped out and taken to a landfill.

3. In more densely populated areas, municipal sewer systems carry wastewater from homes and businesses to centralized treatment locations. There, pollutants are removed by physical, chemical, and biological means. a. At a treatment facility, primary treatment, the physical removal of contaminants in settling tanks or clarifiers, removes about 60% of suspended solids. b. Wastewater then proceeds to secondary treatment, in which water is stirred and aerated so that aerobic bacteria degrade organic pollutants. Roughly 90% of suspended solids may be removed after secondary treatment. c. Finally, the clarified water is treated with chlorine and sometimes ultraviolet light to kill bacteria.

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Key Terms aquifers artesian aquifer confined aquifer consumptive use dam desalination desalinization eutrophic flooding floodplain fresh water groundwater nonconsumptive use nonpoint source oligotrophic point source

primary treatment recharge zone reservoirs runoff secondary treatment septic systems sinkholes surface water unconfined aquifer wastewater water pollution water table watershed wetlands xeriscaping

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Teaching Tips 1. Use the EPA website “Surf Your Watershed” (cfpub.epa.gov/surf/locate/ index.cfm) to retrieve information about water quality in your area.

2. Use activities from “Water on the Web” (waterontheweb.org) to teach the ecology of lakes and streams. The site contains online lessons designed for entry-level college students that use actual data to explore basic science concepts. Topics covered include the chemistry and physics of waterways, the ecological principles involved, human influences, and waterway management.

3. To find out how to conserve water, go to the Virtual House Tour at www.h2ouse.org. Have students look at the ways they can save money in their own homes. Ask them to bring in their water bills for a 12-month period and click on the Water Budget Calculator. By entering details about their living situations, along with their ZIP codes, students can obtain an assessment comparing their actual water use and actual cost against estimated allocations and costs if water conservation methods were used.

4. Organizing a Research Project or a Problem/Case Study When having students do research projects or problem-solving/brainstorming activities in groups, have them use the four-column method. In a small class, give each group two large sheets of paper to write on, then let them post the sheets on the wall for their small group discussion or for presentation to the whole class. In a large class, have students work on notebook paper or 11"14" paper in their small groups. a. Draw a line down the center of the paper lengthwise and a second line across the top of the paper, about 2 inches from the top. This forms a “T-chart.” b. Label the first column of the first sheet “Facts” and the second column “Hypotheses.” On the second sheet, label the first column “Want to Know” and the second column “Learning Topics.” c. In the “Facts” column, have students write all the facts they already know about the issue, either from the text, class lectures, their own background knowledge, or other resources. d. In the second column, have the students hypothesize about possible causes or possible solutions, depending on the initial problem you gave them. e. In the third column, have them keep track of the items they need to know to resolve the issue. f. Finally, in the last column, have the students organize a list of items that they need to do further research on, with each student taking on an item to research.

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Additional Resources Websites 1. Freshwater Ecosystems, Missouri Botanical Garden (mbgnet.mobot.org/fresh) This online resource provides information about rivers, streams, ponds, lakes, and wetlands. For each ecosystem type, there are photographs and diagrams illustrating basic concepts.

2. Water on the Web, University of Minnesota and National Science Foundation (waterontheweb.org) Water on the Web provides water quality data in real-time and archived formats through Remote Underwater Sampling Stations (RUSS). There are hands-on science lessons for high school and undergraduate students.

3. Water Resources of the United States, US Geological Survey (www2.usgs.gov/water) This resource serves as a link to data, information, and lessons about water science.

4. Water, US Environmental Protection Agency (www.epa.gov/aboutepa/aboutoffice-water) This online site from the EPA provides information about water quality across the United States.

5. Killing the Colorado: The Water Crisis in the West, 2016, ProPublica (www.propublica.org/series/killing-the-colorado) This multi-part series investigates the causes and effects of the use of the Colorado River in the Western United States.

Audiovisual Materials 1. American Experience: Hoover Dam, 2006, PBS Home Video (www.pbs.org/wgbh/americanexperience/films/hoover/) This PBS program shows the story of the building of the Hoover Dam on the Colorado River.

2. Crapshoot: The Gamble with Our Wastes, 2003, National Film Board of Canada Production, distributed by Bullfrog Films (www.bullfrogfilms.com) This program examines the failure of our current sewage disposal system and presents alternatives to existing processes.

3. Thirst, 2004, PBS, from the innovative P.O.V. (Point of View) documentary series, available through Bullfrog Films (www.pbs.org/pov/watch/thirst/)

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This raises questions about whether water is a human “rights” issue or a commodity sold from the global commons for profit. It follows several communities in their struggle to determine the fate of water distribution in their area.

4. Killing the Colorado, 2016, Discovery Channel, available through Amazon or Netflix.

Investigates the causes and consequences of water use in the American West.

Weighing the Issues Reaching for Water Facts to consider: These desert cities might get water from areas with more precipitation—that is, states and countries either significantly above or below the 30th parallel. They also might get water from areas with deeper aquifers such as the Ogallala Aquifer. Or, because these three cities are part of the Colorado River watershed, they may demand a larger share of the Colorado River water. In reality, these areas don’t have water resources that are not already committed economically or environmentally.

Even if desert cities could contract for such water, there would be significant obstacles, such as the high cost of the water contract, the high cost of the water transportation and distribution systems, the limited availability of water in dry years or under other circumstances, and the competition with other water-poor areas. People living in the more water-rich areas and agencies responsible for their environment would likely also raise objections that such a water transfer would harm the economy and the environment of the source region. Alternatives for obtaining new water sources include water conservation, increased use of water-efficient devices and procedures, desalinization, municipal water recycling, and economic incentives that promote demand-side reduction of water.

Sludge on the Farm Facts to consider: The use of treated solid sludge as a soil amendment has been practiced for at least 30 years. When applied correctly, the process poses minimal risk due to chemical toxins, biological toxins and pathogens, insects, and odor. Through the Clean Water Act, the Environmental Protection Agency developed standards to regulate the levels of toxins and pathogens present in biosolids, including heavy metals and pathogens. It also deemed the use of unprocessed sludge illegal because processing kills almost all pathogens and removes heavy metals (www.epa.gov/agriculture/tfer.html).

However successful the program of sludge use in agriculture may be, there are still scientists who believe that caution and long-term studies are needed to determine the true consequences. There have been a somewhat large number of anecdotal accounts blaming sludge on ailments associated with exposure to heavy metals or pathogens found in raw sewage (http://cwmi.css.cornell.edu/sewagesludge.htm).

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The Science behind the Story Are We Destined for a Future of “Megadroughts” in the United States?

Observation: California is facing continued drought.

Hypothesis: This pattern will also appear in the American Southwest and Great Plains.

Experiment: Climate scientists compared the climate of the Southwest and Central Plains over the past 1,000 years, gleaned from natural archives of climate such as tree rings, with predictions of their climates over the next 100 years based on computer simulations. To predict the future climate of the southwestern United States and the Central Plains, the researchers used 17 climate models and ran simulations based on a “business-as-usual” scenario, in which the growth in greenhouse gas emissions followed current trends, or based on a “moderatereduction” scenario, in which growth in greenhouse gas emissions was more modest.

Results: When the researchers combined data from the past, present, and future, the results were stunning—and troubling. The climate models predicted unprecedented levels of drought in both regions through 2100, with high levels of agreement between the 17 climate models and the three measures of soil moisture.

The models also concluded that human-induced climate change, and not natural variability in climate, would be the driving force for drier soils in the Southwest and Central Plains.

Implications: If greenhouse gases are reduced, the chance of a multidecade drought drops to 60% to 70% for the Central Plains but remains above 80% for the Southwest, providing yet another incentive for combating global climate change.

What’s Killing Smallmouth Bass in the Potomac River Watershed?

Observation: In 2002, a large fish kill of smallmouth bass (Micropterus dolomieu) occurred in the Shenandoah and South Branch Potomac rivers.

Study: Vicki Blazer, a researcher with the U.S. Geological Survey (USGS) in West Virginia, noticed that a large percentage of male fish contained oocytes— immature eggs in their testes. Although this intersex condition is not unheard of, the rates in the South Branch Potomac River were drastically higher than normal, with 50–75% of male fish displaying intersex characteristics. Blazer hypothesized that smallmouth bass in the river were being exposed to endocrine-disrupting 244 ..

chemicals, causing males to develop eggs. The USGS attempted to identify possible sources of endocrine disruptors by correlating the rate of the intersex condition in fish collected from the Potomac Basin with the characteristics of the section of the river in which they were found.

Results: Fish showed the highest rates of intersex condition at collection sites where human population density was highest and agriculture was the most intensive, providing leads on the possible origins of the endocrine disruptors affecting smallmouth bass. In addition, researchers determined that exposure to endocrine-disrupting chemicals that mimic estrogen adversely affected the functioning of the immune system in fish and led to increased susceptibility to pathogenic bacteria, fungi, and viruses, which led to the fish kills. Researchers continue to search for the source of the endocrine-disrupting chemicals.

Local Connections Fracking is undertaken only in areas where the local geology contains a great deal of shale rock that holds significant reserves of natural gas or petroleum. Where are the closest fossil-fuel-bearing shale deposits in your region? Are those areas waterstressed? Do special economic considerations or ecological considerations exist that would affect any decisions to allow hydraulic fracturing there?

Class time: 30 minutes— one class.

To begin, have students study the map in Figure 15.2. After they have identified the closest location and the degree of water stress, allow them to use the Internet to investigate the ecological and economic considerations that may affect decisions related to fracking in the area.

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Calculating Ecological Footprints Annual water use with standard showerheads (gallons)

Annual water use with low-flow showerheads (gallons)

Annual water savings with lowflow showerheads (gallons)

14,600

7,300

7,300

Your class

Answers will vary

Answers will vary

Answers will vary

Your state

Answers will vary

Answers will vary

Answers will vary

United States

4.8  1012

2.4  1012

2.4  1012

You

1. You would save 1460 gallons.

2. You would save 1825 gallons.

3. You save more water by shortening your shower with a 2.5 gpm showerhead.

4. Answers will vary, but should be along the lines of: Are there any leaking pipes? Are you sure you are taking a shower for the prescribed amount of time?

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16 Marine and Coastal Systems and Resources Chapter Objectives This chapter will help students: Identify physical, geographic, and chemical aspects of the marine environment Explain how the oceans influence and are influenced by climate Describe major types of marine ecosystems Assess impacts from marine pollution Describe the state of ocean fisheries and the reasons for their decline Evaluate marine protected areas and reserves as solutions for conserving biodiversity

Lecture Outline I.

Central Case Study: A Sea of Plastic in the Middle of the Ocean A. In 1997, Captain Charles Moore, of the oceanographic research vessel the Alguita, discovered a large collection of plastic debris in the Pacific Ocean.

We now call this the Great Pacific Garbage Patch.

B. The Great Pacific Garbage Patch is a 1.6 million km2 aggregation of floating debris and plastics in the North Pacific Gyre.

C. The North Pacific Gyre has two garbage patches: one at the eastern edge of the gyre and one at the western edge.

D. Plastic can harm marine creatures when they become entangled and drown or when they ingest plastic pieces.

E. Plastic is designed to not break down and can drift for centuries before degrading, settling to the bottom, or washing up on beaches.

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F. When plastic does degrade, it breaks into smaller pieces (called microplastics). The oceans are now filled with trillions of tiny plastic particles.

G. Organisms can mistake the small pieces of plastic for plankton or fish eggs, ingest them, and suffer injury or death.

H. Plastics that sink to the bottom encounter low temperature and low light conditions that are not favorable for degradation.

I.

Floating pieces of plastic can serve as rafts and transport species over long distances. Some of these transported species can become invasive in their new ecosystems.

J. Plastics can also have toxic effects on organisms.

1. Some plastics contain toxic substances, such as bisphenol A or phthalates, that can leach into the ocean water or the digestive tracts of animals.

2. Plastics can also “grab” and concentrate persistent organic pollutants (POPs) such as DDT and PCBs, thereby contaminating the plastic and increasing its toxicity to any organism that ingests it.

K. Because plastics take 50 to 600 years to degrade at sea, there is no viable way to collect the small bits of plastics in the ocean. Preventing their entry into the ocean is the key to remedying the oceanic plastic pollution.

L. Oceans are accumulating plastic wastes at a high rate. Every year, approximately 8 million metric tons of plastic are added to the 200 million metric tons already in the ocean.

M. Reducing single-use plastic and preventing its entry into the ocean is the key to solving this environmental issue.

II.

The Oceans 1. The world’s five oceans—the Pacific, Atlantic, Indian, Arctic, and Southern—are all connected, making up a single vast body of water. This “world ocean” covers 71% of the Earth’s surface and contains 97.5% of its water.

A. Seafloor topography can be rugged.

1. Stylized maps that reflect bathymetry (the measurement of ocean depths) and topography (physical geography, or the shape and arrangement of landforms) illustrate underwater geographic features. a. In a bathymetric profile, gently sloping continental shelves sit beneath the shallow waters bordering the continents.

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2. Wherever reefs, volcanism, or other processes create physical structures underwater, life thrives.

B. Ocean water contains high concentrations of dissolved salts.

1. Ocean water contains approximately 96.5% H2O by mass. Most of the remainder consists of ions from dissolved salts. a. Ocean water is salty primarily because ocean basins are the final repositories for runoff, which collects salts from weathered rocks and carries them, along with sediment, to the ocean. b. The water in the ocean evaporates but the salts do not, and they accumulate in ocean basins.

2. The salinity of ocean water generally ranges from 33,000 to 37,000 parts per million, varying from place to place because of differences in evaporation, precipitation, and freshwater runoff from land and glaciers.

3. Besides dissolved salts, nutrients such as nitrogen and phosphorus occur in seawater in trace amounts (well under 1 part per million) and play essential roles in nutrient cycling in marine ecosystems.

C. Solar energy stratifies ocean water.

1. Warmer water is less dense than cooler water, but water also becomes denser as it gets saltier. a. Waters of the surface zone are heated by sunlight and are stirred by wind such that they are of similar density down to a depth of about 150 m (490 ft). b. Below this zone lies the pycnocline, a region in which density increases rapidly with depth. The pycnocline contains about 18% of ocean water by volume, compared with the surface zone’s 2%. c. The remaining 80% lies in the deep zone beneath the pycnocline. The dense water in this deep zone is sluggish and unaffected by winds, storms, sunlight, and temperature fluctuations.

2. Despite the daily heating and cooling of surface waters, ocean temperatures are much more stable than temperatures on land. The reason for this stability is that water has a high heat capacity, a measure of the heat required to increase temperature by a given amount.

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D. Surface water flows horizontally in currents.

1. Earth’s ocean is composed of currents—vast, riverlike flows driven by density differences, heating and cooling, gravity, and wind.

2. Besides influencing climate, ocean currents have aided navigation and shaped human history.

E. Water also flows vertically in the oceans.

1. Where horizontal surface currents diverge from one another, cold, deep waters are pulled to the surface in a process called upwelling.

2. In areas where surface currents converge, or come together, surface water sinks—a process called downwelling.

F. Ocean currents affect Earth’s climate.

1. Thermohaline circulation is a worldwide current system in which warmer, lower-salinity water moves along the surface and colder, saltier water (which is denser) moves horizontally deep beneath the surface. The now cooler water becomes saltier through evaporation and thus becomes denser and sinks, creating a region of downwelling known as the North Atlantic Deep Water (NADW).

2. Scientists hypothesize that interrupting thermohaline circulation could trigger rapid climate change.

3. Another interaction between ocean currents and the atmosphere that influences climate is the El Niño–Southern Oscillation (ENSO), a systematic shift in atmospheric pressure, sea surface temperature, and ocean circulation in the tropical Pacific Ocean.

4. El Niño conditions are triggered when air pressure decreases in the eastern Pacific and increases in the western Pacific, weakening the equatorial winds and allowing the warm water to flow eastward.

5. La Niña events are the opposite of El Niño events; in a La Niña event, unusually cold waters rise to the surface and extend westward in the equatorial Pacific when winds blowing to the west strengthen, and weather patterns are affected in opposite ways.

III.

Marine and Coastal Ecosystems A. Intertidal zones undergo constant change.

1. Where the ocean meets the land, intertidal, or littoral, ecosystems spread between the uppermost reach of the high tide and the lowest limit of the low tide.

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a. Tides are the periodic rising and falling of the ocean’s height at a given location, caused by the gravitational pull of the moon and sun.

2. The intertidal environment is a tough place to make a living, but it is home to a remarkable diversity of organisms.

3. The rocky intertidal zone is so diverse because environmental conditions change dramatically from the high to low reaches.

B. Salt marshes line temperate shorelines.

1. Along many of the world’s coasts at temperate latitudes, salt marshes occur where the tides wash over gently sloping sandy or silty substrates.

2. Salt marshes boast very high primary productivity and provide critical habitat for shorebirds, waterfowl, and many commercially important fish and shellfish species.

C. Mangrove forests line coasts in the tropics and subtropics.

1. Mangroves are among the few types of trees that are salt tolerant, and they have rather unique roots. Some of their roots curve upward like snorkels to get oxygen from the air while others curve downward like stilts to support the tree in changing water levels.

2. When mangroves are removed, coastal areas lose the ability to slow runoff, filter pollutants, and retain soil.

D. Fresh water meets saltwater in estuaries.

1. Many salt marshes and mangrove forests occur in or near estuaries, water bodies where rivers flow into the ocean, mixing fresh water with saltwater.

2. Estuaries everywhere have been affected by coastal development, water pollution, habitat alteration, and overfishing.

E. Kelp forests harbor many organisms.

1. Kelp is a large, brown algae.

F. Coral reefs are treasure troves of biodiversity.

1. A coral reef is a mass of calcium carbonate composed of the shells of tiny marine animals known as corals.

2. Corals are tiny invertebrate animals related to sea anemones and jellyfish. Corals also derive nourishment from symbiotic algae known as zooxanthellae, which inhabit their bodies and produce food through photosynthesis (and provide the diversity of vibrant colors in reefs).

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3. Like kelp forests, coral reefs protect shorelines by absorbing wave energy.

4. Coral reefs are experiencing alarming declines worldwide as a result of coral bleaching caused by pollution and increased sea surface temperature.

5. A few coral species thrive in waters outside the tropics and build reefs on the ocean floor at depths of 200–500 m (650–1650 ft).

G. Open-ocean ecosystems vary in their biodiversity.

1. Regions of ocean water differ greatly, and some zones support more life than others. a. The uppermost 10 m (33 ft) of water absorbs 80% of solar energy, so nearly all of the oceans’ primary productivity occurs in the top layer, or photic zone. b. Habitats and ecosystems occurring between the ocean’s surface and floor are termed pelagic. c. Those that occur on the ocean floor are called benthic.

2. Primary production and animal life are concentrated in regions of nutrient-rich upwelling.

3. In the little-known deep-water ecosystems, animals have adapted to tolerate extreme water pressures and to live in the dark without food from autotrophs.

4. Ecosystems form around hydrothermal vents on the bottom of the deep ocean, where heated water spurts from the seafloor, carrying minerals that precipitate to form rocky structures.

IV.

Marine Pollution A. Plastics are long-lived in marine environments.

1. Organisms can become entangled and drown in large pieces of plastic debris, or they may die as a result of ingesting material that they cannot digest or expel.

2. Because plastic is designed not to break down, it can drift for decades before degrading or washing up on beaches.

3. Up to 30% of the plastics entering the ocean are carried there by rivers and 90% comes from 10 rivers in East Asia, South Asia, and Africa. a. Inadequate sanitation in these areas allows plastics in open-air dumps to be blown or washed into waterways.

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B. Oil pollution comes from spills of all sizes.

1. Much of the oil entering the ocean from sources other than seeps accumulates in waters from innumerable, widely spread, small nonpoint sources.

2. In 2010, the Deepwater Horizon offshore drilling platform exploded and sank into the Gulf of Mexico off the Louisiana coast.

Hundreds of miles of coastal areas along the Gulf Coast were affected.

3. Over the past three decades, the amount of oil spilled by tankers worldwide has decreased, in part because of an increased emphasis on spill prevention and response.

C. Toxic pollutants can contaminate seafood.

1. Mercury is a toxic heavy metal released into the environment from coal combustion, mine tailings, and other sources.

2. Because seafood is an important part of a healthy diet, nutritionists do not advocate avoiding seafood entirely. However, people in at-risk groups should avoid fish high in mercury (such as swordfish, shark, and albacore tuna) while continuing to eat seafood low in mercury (such as catfish, salmon, and canned light tuna).

D. Excess nutrients cause eutrophication and algal blooms.

1. Excessive nutrient concentrations sometimes give rise to population explosions among some species of marine algae. These dinoflagellate algae produce powerful toxins that attack the nervous systems of vertebrates. Blooms of these algae are known as harmful algal blooms. a. Some dinoflagellate species produce reddish pigments that discolor surface waters, and blooms of these species are nicknamed red tides.

E. Light and sound pollution can disorient marine organisms.

1. Many organisms use light as a cue to guide their behavior, and artificial lights have been found to alter the behavior of marine invertebrates, reptiles, fish, and birds.

2. Loud underwater sounds, such as sonar used by the military to detect submarines, can damage the sensitive echolocation organs in whales and dolphins. This can cause the animals to dangerously flee an area and can sometimes result in mass strandings.

F. Climate change is altering ocean chemistry.

1. The first concern with this is that the ocean’s surface water may soon become saturated with as much CO2 as it can hold. Once it 253 ..

reaches this limit, then climate change will accelerate because the oceans will no longer remove large amounts of carbon dioxide from the atmosphere.

2. The second concern is that as ocean water soaks up CO2, it becomes more acidic. As ocean acidification proceeds, sea creatures such as corals, snails, and mussels have difficulty forming shells because the carbonate ions (CO32–) they need to create them become less available with increasing acidity, and elevated acidity levels can cause the shells of sea creatures to even begin dissolving.

V.

Emptying the Oceans 1. Most scientists agree that overharvesting of fish is the largest environmental issue related to the marine environment.

2. Around 60% of the world’s wild fisheries are fully exploited. More than 30% of wild marine fish populations are overexploited. Only 10% of the world’s marine fish populations can yield more than they are already yielding.

A. Industrialized fishing facilitates overharvesting.

1. Today’s industrialized commercial fishing fleets employ massive ships and powerful new technologies to find and capture fish in great volume.

2. The modern fishing industry uses several methods to capture fish at sea that are highly efficient but also environmentally damaging. a. In purse seining, vessels deploy large nets, some as long as a kilometer, around schools of fish near the surface. The nets are suspended in the upper water column by floating buoys on the net top and weights on the net bottom. Once the school of fish is encircled, the net is drawn shut like a laundry bag (or the hood on a sweatshirt) by the purse line, a rope running through the top of the net. b. Some vessels set out long driftnets that span large expanses of water. Drift netting usually targets species that traverse open water in immense schools, such as herring, sardines, and mackerel. c. Longline fishing involves setting out extremely long lines (up to 80 km [50 mi] long) with up to several thousand baited hooks spaced along their lengths. d. Trawling entails dragging immense cone-shaped nets through the water, with weights at the bottom and floats at the top.

Trawling in open water captures pelagic fish, whereas bottom 254 ..

trawling involves dragging weighted nets across the floor of the continental shelf to catch groundfish and other benthic organisms, such as scallops.

B. Wild fisheries collapse quickly under intensive harvest.

1. The oceans today contain only one-tenth of the large-bodied animals they once did.

2. An example of the consequences of overfishing can be seen in the Atlantic cod fishery. a. For centuries, the Grand Banks provided ample fish. b. By the 1960s, massive industrial trawlers began harvesting fish in record numbers. c. Catches dwindled in the 1970s because too many fish had been harvested and because bottom trawling had destroyed huge expanses of the cod’s habitat. d. In the 1990s, a moratorium on fishing was instituted to allow the fishery to rebound. e. Today, the fishery seems to be recovering.

C. The growth of aquaculture—as well as other factors—has masked the collapse of large fisheries.

1. The growth of aquaculture—the raising of fish, seafood, and other forms of marine life for human consumption—has allowed the supply of seafood to remain relatively stable.

D. We are “fishing down the food chain.”

1. Analyses of fishery data reveal that as fishing increases, the size and age of the fish caught decline.

2. In addition, as particular species become too rare to fish profitably, fleets begin targeting other species that are more abundant.

3. Some of these species were undesirable ones that fishermen formerly threw back when fishing for more marketable species, but underwent “image makeovers” to aid their sale to consumers.

E. Industrialized fishing kills nontarget animals and damages ecosystems.

1. Bycatch, the accidental capture of animals, accounts for the deaths of millions of fish, sharks, marine mammals, and birds each year.

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VI.

Marine Conservation A. Loss of marine biodiversity erodes ecosystem services.

B. We can protect unique and biodiverse areas in the ocean.

1. Hundreds of marine protected areas (MPAs) have been established, mostly along coastlines of developed countries. Nearly all MPAs allow fishing or other extractive activities.

2. Because of the lack of true refuges from fishing pressure, many scientists want to establish areas where fishing is prohibited. Such no-take areas have come to be called marine reserves. a. Data from marine reserves around the world have indicated that reserves can work as win-win solutions that benefit ecosystems, fish populations, and fishing economies.

Key Terms benthic continental shelves coral reef corals currents downwelling El Niño El Niño–Southern Oscillation (ENSO) estuaries Great Pacific Garbage Patch harmful algal blooms heat capacity intertidal kelp La Niña

mangroves marine protected areas (MPAs) marine reserves North Atlantic Deep Water (NADW) ocean acidification pelagic photic zone pycnocline red tides salt marshes thermohaline circulation tides upwelling zooxanthellae

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Teaching Tips 1. Provide students with information about a marine sanctuary found in or near your region. There are a growing number of sanctuaries in the United States and information about them can be found at sanctuaries.noaa.gov.

2. This chapter introduces several ocean habitats such as mangroves and seagrass beds, kelp forests and coral reefs, and tidepools and salt marshes. Emphasize that these ecosystems serve as nurseries for many juvenile fish and invertebrates. Assign groups of students to study various ocean habitats (all of the above, plus barrier islands and barrier reefs, polar ice caps, pelagic and deep-water habitats, and ocean vents, for instance) and have each group create a poster or presentation on the locations around the world, the food webs, major threats to the area posed by humans, and the area’s importance to our way of life.

3. Use tide tables to teach the concept of tides. Tide tables that show predicted high and low tides at sites across the country can be accessed from NOAA at tidesandcurrents.noaa.gov. The site has both tables and graphs that can be displayed in a variety of ways.

One suggestion is to create a tidal graph for the period from Aug. 24 through Sept. 10, 2005, for the East Bank 1, Norco—the measuring station at the southwestern edge of Lake Ponchartrain, Louisiana. This includes the time periods before, during, and after Hurricane Katrina.

For further information about Hurricane Katrina’s effects on the Gulf Coast, read the levee research at http://soundwaves.usgs.gov/2006/01/ and the offshore research at soundwaves.usgs.gov/2006/01/fieldwork3.html.

4. The text discusses overfishing and bycatch in the world’s oceans as well as some of the issues with fish farms. Show students the Monterey Bay Aquarium’s Seafood Watch Web page (www.seafoodwatch.org/), which helps consumers make choices that help keep oceans healthy. The website explains the aquarium’s seafood guides and lists fish and shellfish—domestic, foreign, domestic farmed, and foreign farmed—with recommendations for or against purchase based on the sustainability of the methods used to catch or to raise the organisms. (The only information on mercury contamination is a pocket guide that shows a red asterisk next to those species listed in a mercury advisory from the United States Food and Drug Administration and the Environmental Protection Agency.)

5. Questions are an important tool for instructors, both in classroom interactions and in written materials such as labs, quizzes, and exams. Benjamin Bloom created a Taxonomy of Educational Objectives, which organizes questions into six categories based on the level of thinking involved.

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The first two categories, Knowledge and Comprehension, are informational.

When you ask for a definition or give a set of matching questions on an exam, you are having students recall knowledge, possibly verbatim. You have no way of gauging whether they understand the information; you only know that they have memorized it.

The next two categories, Application and Analysis, involve asking students to apply information to solve a problem or use what they have learned to analyze a new situation. Application may still be at the level of rote memorization (when given a problem of type x, use method y to solve it). Analysis, however, is the beginning of the higher-order thinking skills that we would like to foster in students.

The final two categories, Synthesis and Evaluation, require students to use multiple resources to create new information, develop new ways of looking at current information, or generate appropriate criteria to assess a situation.

In an entry-level course, many of the questions will necessarily be at the Knowledge and Comprehension levels as students learn the terminology and basic concepts. However, it is important to move beyond those levels so students can analyze, synthesize, and evaluate both in-class discussions and written work. This is where the course truly begins to be relevant and applicable to the students’ lives—to the issues that affect their own communities and families.

Bloom’s Taxonomy is also useful as you plan a course. You will want to ensure that some of your course objectives are drawn from the higher levels of thinking.

Additional Resources Websites 1. National Marine Sanctuaries, National Oceanic and Atmospheric Administration, US Department of Commerce (sanctuaries.noaa.gov) This is the official home page for the National Marine Sanctuaries Program, with information about the history and current management of US marine sanctuaries.

2. Secrets of the Ocean Realm, PBS Online (http://www.pbs.org/oceanrealm) This website provides information and classroom activities about unique and fascinating creatures that inhabit the ocean’s depths.

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3. Office of Wetlands, Oceans, and Watersheds, US Environmental Protection Agency (EPA) (www.epa.gov/aboutepa/about-office-water#wetlands) This website provides information about projects and programs that are managed by the EPA’s Office of Wetlands, Oceans, and Watersheds.

4. Ocean Conservancy (www.oceanconservancy.org) Ocean Conservancy promotes healthy and diverse ocean ecosystems and opposes practices that threaten ocean life and human life. Through research, education, and science-based advocacy, Ocean Conservancy informs, inspires, and empowers people to speak and act on behalf of the oceans. In all its work, Ocean Conservancy strives to be the world’s foremost advocate for the oceans.

Projects include restoring sustainable North American fisheries, protecting wildlife from human impact, conserving special ocean places, and reforming government for better ocean stewardship.

Audiovisual Materials 1. Oceans, 2008, produced and distributed by BBC Earth (www.bbcearth.com/oceans/) Oceans is an eight-part BBC series that seeks to provide a better understanding of the state of the Earth’s oceans today; their role in the past, present, and future; and their significance in global terms.

2. The Blue Planet, 2001, produced by the BBC (www.bbc.co.uk/programmes/b008044n) Described as “the first-ever comprehensive series on the natural history of the world’s oceans,” each of the eight 50-minute episodes examines a different aspect of marine life. The underwater photography includes creatures and behavior that had previously never been filmed.

3. Coral Reef Adventure, 2003, video produced and distributed by MacGillivray Freeman Films (www.coralfilm.com) This IMAX film follows two divers as they explore South Pacific reefs, documenting problems with overfishing, sedimentation, and coral bleaching.

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Weighing the Issues Coastal Development Facts to consider: Students will respond individually to this question. However, there are factors to take into account. Regarding real estate, people desire to live and do business along coasts, so this property initially will be valuable, but less so as it becomes more developed. Also, salt marshes stabilize shorelines against storm surges. Removing them leaves the area less sheltered for new buyers.

Regarding wildlife, salt marshes boast very high primary productivity and provide critical habitat for shorebirds, waterfowl, and many commercially important fish and shellfish. On a larger scale, salt marshes filter pollution, affecting water quality in the region to be developed. These factors should be taken into effect as students formulate their responses.

Eating Seafood Facts to consider: This is a controversial topic, as altering one’s diet can be a big lifestyle change. Therefore, each student might give a slightly different answer.

After being presented with the information in this chapter on the accumulation of toxins, such as mercury, by biomagnification and bioaccumulation in fish and other wildlife, students should view this as a real threat to what ends up on their plates. Also, after reading that fish are not sustainably harvested, students should know how to make informed purchases. Surely, consumer input could influence fishing practices—if there is no market to sell the product, no profit will be made.

But mercury contamination is a different story, as one is not just making a lifestyle change in cutting out the contaminated source, but also the products that created the contamination to begin with.

Preservation at Sea Facts to consider: This question requires an individual response. We humans are more likely to notice changes in land ecosystems than in marine ecosystems simply because we live on land. It is more challenging for us to observe the oceans, especially deep-water ecosystems. For most of human existence, people’s sense of marine ecosystem health has been based on the abundance of food resources—as long as we have found new ways to harvest from the sea, the general sense has been that such resources are boundless. In addition, the oceans seem to absorb maltreatment without apparent harm, such as when untreated garbage and wastewater are dumped into offshore areas. Interestingly, our response to garbage and other waste being washed up on shorelines has been to dump the waste farther offshore, regardless of its effect on deep-water ecosystems and deep-water currents.

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The Science behind the Story Can We Predict the Oceans’ “Garbage Patches?”

Observation: Captain Charles Moore encountered a huge floating mass of debris he described as a “soupy” collection of items including tires, plastics, chemical drums, coat hangers, fishing nets, and other items. This was the first recorded visual confirmation of what is now called the “Great Pacific Garbage Patch” and brought firmly into the public eye the issue of plastic pollution in the oceans.

Question: Is there any way to know where to look for them?

Study: Since 1979, more than 12,000 buoys have been deployed in the world’s oceans and researchers have tracked their movements to determine patterns in ocean currents. In 2008, Maximenko partnered with Peter Niiler of the Scripps Institution of Oceanography to use data from the Global Drifter program to produce a more detailed map of surface ocean currents. He also partnered with his colleague, Jan Hafner, and created a computer model that predicted the movements of drifters over long time periods in the world’s oceans. He then ran a simulation in which he uniformly distributed drifters in the oceans and saw where drifters concentrated over time.

Results: The simulation’s results, published in 2012 in Marine Pollution Bulletin, revealed that oceanic debris was likely to accumulate in portions of five subtropical gyres.

Inventorying the Great Pacific Garbage Patch Questions: Is most marine plastic debris from land-based or marine-based sources? How does the open ocean affect plastic degradation?

Experiment: Oceanographer Julia Reisser and her team from the Ocean Cleanup Foundation surveyed the Great Pacific Garbage Patch (GPGP) by conducting more than 650 trawls and by surveying the GPGP from the air. They inventoried the items collected in the trawls and detected in the aerial surveys. Then, they worked with Laurent Lebreton to process the data and generate a model that explains the nature of the debris in the GPGP, changes in debris concentrations over time, and the relative size of the GPGP over time.

Results: The model estimated that the total mass of floating plastics in the patch— 79,000 metric tons—was 4–16 times higher than other estimates. More than 75% of the total mass of the debris in the GPGP was from large pieces of debris. Nearly half (46%) of the debris was discarded fishing nets. Microplastics made up only 8% of the mass of the debris collected, but represented 94% of the 1.8 trillion 261 ..

pieces of debris estimated to be floating in the GPGP. The study found products from 12 different nations, with 30% from Japan and 30% from China. Most of the plastics were produced since 2000, but they found items dating back to 1977.

Rigid plastics were found in high quantities, but film plastics were not. The researchers hypothesized that films, with their high surface-to-volume ratios, likely do not persist for long in the marine environment.

Local Connections Six U.S. states have banned the use of plastic bags, and others add taxes to plastic bags to discourage their use or actively support programs that promote the recycling and reuse of plastic bags. On the other end of the spectrum, 10 states have passed legislation that prevents cities within those states from enacting local restrictions on the use of plastic bags. Where does your state stand on the issue?

Where do you think your state should stand?

Class time: 10 minutes – one class period This activity could be completed as a homework assignment or as a class exercise.

If it were completed during class time, it could be an interesting topic for a class debate. After allowing students time to research how their state stands on this issue, the class could be divided into two groups: one supporting the bag ban and one opposing the bag ban. Give the two groups 30 minutes to develop their argument and then hold a short debate over the merits of a bag ban. Encourage the students to think about how the ban would affect the environment, the economy, and the consumers of their state.

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Calculating Ecological Footprints Consumer group

Annual consumption North America (21.6 kg per person)

China (41.0 kg per person)

World (20.2 kg per person)

21.6 kg

41.0 kg

20.2 kg

Your class

Answers will vary

Answers will vary

Answers will vary

Your state

Answers will vary

Answers will vary

Answers will vary

United States

7.07  10 kg

1.34  10 kg

6.61  109 kg

World

1.67  1011 kg

3.16  1011 kg

1.56  1011 kg

You

9

10

1. North American versus world fish consumption: 21.6 kg/20.2 kg = 1.07. North American versus world ecological footprints: three-nation average of ~6.1 hectares/2.7 hectares ~2.26. Regarding fish consumption, North America is not as far above the world average as compared to its ecological footprint as a whole. This may be because seafood is more prevalent in many other cuisines around the world. We are, however, still above the world average.

2. China’s large population already has an ecological footprint that exceeds the land area of its country. To feed that population, they must either import food from other countries, or harvest food from a common area that is part of no country (i.e., Earth’s oceans).

3. Answers will vary, but globally, fisheries are already suffering from overexploitation. The total human impact on those fisheries is the product of our population size and our per capita consumption rates, so if both are increasing, their product will increase even more quickly. The ecological consequences of such overexploitation may not be reversible, and numerous marine species could be driven to extinction. Possible solutions include removing fish from the diet or eating only sustainably farmed or caught fish species.

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17 The Atmosphere, Air Quality, and Pollution Control Chapter Objectives This chapter will help students: Describe the composition, structure, and function of Earth’s atmosphere Relate weather and climate to atmospheric conditions Identify major outdoor air pollutants, and outline the scope of air pollution Assess strategies and solutions for control of outdoor air pollution Explain stratospheric ozone depletion and identify steps taken to address it Define acid deposition, discuss its consequences, and explain how we are addressing it Characterize the scope of indoor air pollution, and assess solutions

Lecture Outline I.

Central Case Study: Clearing the Air in Los Angeles and Mexico City A. For Americans, Los Angeles has long symbolized air pollution.

B. One city that looked to Los Angeles’s efforts as it planned its own responses to smog was Mexico City, the capital of Mexico and one of the world’s largest metropolises.

C. Not long ago, Mexico City suffered the most polluted air in the world.

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D. As in Los Angeles, traffic generates most of the pollution in Mexico City, where motorists in nearly 7 million cars sputter across miles of urban sprawl. And like L.A., Mexico City lies in a valley surrounded by mountains, making it vulnerable to temperature inversions that trap pollutants over the city.

E. Despite the challenges facing the world’s sixth-largest metropolis, Mexico City’s 21 million people fought back and made notable improvements in air quality.

F. By 2010–2015, most pollutants had been slashed by more than 75%, and the air was meeting health standards on one of every two days.

G. Plenty of hurdles remain.

H. L.A. and Mexico City typify cities of developed and developing nations today.

II.

The Atmosphere 1. The atmosphere is the layer of gases that envelops our planet.

2. Earth’s atmosphere consists of 78% nitrogen (N2) and 21% oxygen (O2) by volume of dry air. The remaining 1% is composed of argon (Ar) and minute concentrations of water vapor and other gases.

3. Over our planet’s long history, the atmosphere’s composition has changed.

A. The atmosphere is layered.

1. The atmosphere consists of four layers that differ in temperature, density, and composition.

2. The bottommost layer, the troposphere, blankets Earth’s surface and provides us the air we breathe.

3. The stratosphere extends 11–50 km above sea level, its temperature rising gradually with altitude. Most of the atmosphere’s ozone concentrates in a portion of the stratosphere roughly 17–30 km above sea level, a region we call the ozone layer. The ozone layer greatly reduces the amount of ultraviolet (UV) radiation that reaches Earth’s surface.

4. Above the stratosphere lies the mesosphere, where temperatures decrease with altitude and where incoming meteors burn up. Above this, the thermosphere extends upward to an altitude of 500 km.

Still higher, the atmosphere merges into space in a region called the exosphere.

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B. Pressure, humidity, and temperature vary within the atmosphere.

1. Atmospheric pressure measures the force per unit area produced by a column of air and decreases with altitude, because at higher altitudes there are fewer molecules being pulled down by gravity.

2. Relative humidity is the ratio of water vapor that air contains at a given temperature to the maximum amount it could contain at that temperature.

3. The temperature of air varies with location and time.

C. The sun’s energy influences weather and climate.

1. Of this solar energy, about 70% is absorbed by the atmosphere and planetary surface while the rest is reflected back into space.

2. The spatial relationship between Earth and the sun determines how much solar radiation strikes each point on Earth’s surface.

3. Because Earth is tilted on its axis (an imaginary line connecting the poles, running perpendicular to the equator) by about 23.5 degrees, the Northern and Southern Hemispheres end up being tilted toward the sun for half of each year, resulting in the seasons.

4. On the surface of our planet, land and water absorb solar energy and then emit thermal infrared radiation, which warms the air and causes some water to evaporate. The difference in air temperatures at different altitudes sets into motion a process of convective circulation as warm air rises, cools, and descends past other warm air that is rising.

5. Weather specifies atmospheric conditions in a location over short time periods, typically minutes, hours, days, or weeks. Climate, in contrast, describes typical patterns of atmospheric conditions in a location over long periods of time.

D. Inversions affect air quality.

1. Under most conditions, air in the troposphere becomes cooler as altitude increases. Because warm air rises, vertical mixing results.

Occasionally, however, a layer of cool air may form beneath a layer of warmer air. a. This departure from the normal temperature profile is known as a temperature inversion, or thermal inversion. b. The band of air in which temperature rises with altitude is called an inversion layer.

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E. Large-scale circulation systems produce global climate patterns.

1. Near the equator, solar radiation sets in motion a pair of convective cells known as Hadley cells. Two additional pairs of convective cells, Ferrel cells and polar cells, lift air and create precipitation around 60 degrees latitude north and south and cause air to descend at 30 degrees latitude and in the polar regions.

2. The Hadley, Ferrel, and polar cells interact with Earth’s rotation to produce global wind patterns. a. As Earth rotates on its axis, regions of the planet’s surface near the equator move west to east more quickly than regions near the poles. As a result, from the perspective of an Earth-bound observer, air currents of the convective cells that flow north or south appear to be deflected from a straight path. This deflection is called the Coriolis effect.

3. The atmosphere interacts with the oceans to affect weather, climate, and the distribution of biomes.

F. Storms pose hazards.

1. Hurricanes form when warm, moisture-laden air over tropical oceans rises and winds rush into these areas of low pressure.

2. Tornadoes form when a mass of warm air meets a mass of cold air and the warm air rises quickly, setting a powerful convective current in motion.

III.

Outdoor Air Quality 1. Whether from simple wood fires or modern coal-burning power plants, we have generated air pollutants, gases and particulate material added to the atmosphere that can affect climate or harm people or other living things. Air pollution refers to the release of air pollutants.

2. In recent decades, public policy and improved technologies have helped reduce most types of outdoor air pollution (often called ambient air pollution) in industrialized nations.

A. Some pollution is from natural sources.

1. Natural processes also pollute the air.

2. Fires from burning vegetation emit soot and gases.

3. Volcanic eruptions release large quantities of particulate matter as well as sulfur dioxide and other gases into the troposphere.

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4. Winds sweeping over arid terrain can send huge amounts of dust aloft.

B. We create outdoor air pollution.

1. Air pollution can emanate from point sources or nonpoint sources.

2. Pollutants released directly from a source are termed primary pollutants. Ash from a volcano, sulfur dioxide from a power plant, and carbon monoxide from an engine are all primary pollutants.

Often primary pollutants react with one another or with constituents of the atmosphere and form other pollutants; the resulting compounds are called secondary pollutants.

3. Pollutants differ in their residence time, the amount of time a pollutant spends in the atmosphere.

C. The Clean Air Act addresses pollution.

1. To address air pollution in the United States, Congress has passed a series of laws, most notably the Clean Air Act. 2. Under the Clean Air Act, the US Environmental Protection Agency (EPA) sets nationwide standards for: (1) emissions of several key pollutants, and (2) concentrations of major pollutants in ambient air.

D. Agencies monitor emissions.

1. State and local agencies monitor and report to the EPA the emissions of six major pollutants. a. Carbon monoxide (CO) is a colorless, odorless gas produced primarily by the incomplete combustion of fuel. b. Sulfur dioxide (SO2) is a colorless gas with a pungent odor that is released when coal is burned. c. Nitrogen oxides are a family of compounds that include nitric oxide (NO) and nitrogen dioxide (NO2). Nitrogen oxides result when atmospheric nitrogen and oxygen react at high temperatures. d. Volatile organic compounds (VOCs) are carbon-containing chemicals emitted by vehicle engines and a wide variety of solvents, industrial processes, household chemicals, and consumer items. e. Particulate matter is composed of solid or liquid particles small enough to be suspended in the atmosphere and able to damage respiratory tissues when inhaled.

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f. Lead is a heavy metal that enters the atmosphere as a particulate pollutant, released by industrial processes and fuel combustion.

E. We have reduced emissions.

1. Dramatic reductions in emissions have occurred despite significant increases in the nation’s population, energy consumption, miles traveled by vehicle, and gross domestic product.

2. Scrubbers have been installed to chemically convert or physically remove airborne pollutants before they are emitted from smokestacks. Meanwhile, cleaner-burning motor vehicle engines and automotive technologies such as catalytic converters have cut down on pollution from automobile exhaust. In a catalytic converter, engine exhaust reacts with metals that convert hydrocarbons, CO, and NOx into carbon dioxide, water vapor, and nitrogen gas.

F. Air quality has improved.

1. In the United States, the EPA and the states monitor outdoor air quality by measuring the concentrations of six criteria pollutants, pollutants judged to pose substantial risks to human health. For each of these, the EPA has established national ambient air quality standards (NAAQS), which are the maximum concentrations allowable in ambient outdoor air.

2. Nitrogen dioxide is a highly reactive, reddish-brown, foul-smelling gas that contributes to smog and acid deposition.

3. Tropospheric ozone (also called ground-level ozone) is a secondary pollutant, created by the reaction of nitrogen oxides and volatile carbon-containing chemicals in the presence of sunlight.

G. Toxic pollutants pose health risks.

1. Toxic air pollutants are substances known to cause cancer, reproductive defects, or neurological, developmental, immune system, or respiratory problems in people and other organisms.

H. Rural areas also confront pollution challenges.

I. Air pollution remains severe in industrializing nations.

1. Currently, people in the vast sprawling cities of India, China, and other Asian nations suffer the world’s worst air quality.

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J. Smog poses health risks.

1. Smog is a general term for a mixture of air pollutants that can accumulate as a result of fossil fuel combustion, generally over industrial regions or urban areas with heavy automobile traffic.

2. Since the onset of the Industrial Revolution, cities have suffered a type of smog known as industrial smog.

3. Photochemical smog is formed when sunlight drives chemical reactions between primary pollutants and atmospheric compounds, producing a mix of more than 100 different chemicals, tropospheric ozone often being the most abundant.

K. We can take steps to reduce smog.

L. Should we regulate greenhouse gases as air pollutants?

IV.

Ozone Depletion and Recovery 1. Years of dynamic research by hundreds of scientists revealed that certain airborne chemicals destroy ozone, and that most of these ozone-depleting substances are human-made.

A. Synthetic chemicals deplete stratospheric ozone.

1. Researchers identifying ozone-depleting substances pinpointed primarily halocarbons—human-made compounds derived from simple hydrocarbons, in which hydrogen atoms are replaced by halogen atoms such as chlorine, bromine, or fluorine. a. Industry was mass-producing more than 1 million tons per year of one type of halocarbon, chlorofluorocarbons (CFCs).

2. CFCs reach the stratosphere unchanged and can linger there for a century or more.

B. The ozone hole appears each year.

1. In 1985, researchers shocked the world when they announced that stratospheric ozone levels over Antarctica in the southern hemisphere’s springtime had declined by nearly half during just the previous decade, leaving a thinned ozone concentration that was soon named the ozone hole.

2. During the dark and frigid Antarctic winter (June to August), temperatures in the stratosphere dip below –80°C (–112°F), enabling unusual high-altitude polar stratospheric clouds to form.

Many of these icy clouds contain condensed nitric acid, which splits chlorine atoms off from compounds such as CFCs.

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3. In the Antarctic spring (starting in September), sunshine returns and dissipates the clouds, releasing chlorine atoms that begin destroying ozone. The ozone hole lingers over Antarctica until December.

C. We addressed ozone depletion with the Montreal Protocol.

1. Policymakers responded to the scientific concerns, and international efforts to restrict production of CFCs bore fruit in 1987 with the Montreal Protocol. In this treaty, the world’s nations agreed to cut CFC production in half by 1998.

2. Earth’s ozone layer is not expected to recover completely until after 2060.

3. Environmental scientists have attributed the success of the Montreal Protocol to several factors. a. Informative scientific research developed rapidly, facilitated by new and evolving technologies. b. Policymakers engaged industry in helping to solve the problem. c. Implementation of the Montreal Protocol after 1987 followed an adaptive management approach, adjusting strategies in response to new scientific information, technological advances, and economic data.

V.

Addressing Acid Deposition 1. Acid deposition is the deposition of acidic or acid-forming pollutants from the atmosphere onto Earth’s surface.

A. Fossil fuel combustion spreads acidic pollutants far and wide.

1. Acid deposition often takes place by precipitation (commonly referred to as acid rain) but also may occur by fog, gases, or the deposition of dry particles. Acid deposition is one type of atmospheric deposition, which is the wet or dry deposition on land of a wide variety of pollutants.

B. Acid deposition has many impacts.

1. Acids leach nutrients such as calcium, magnesium, and potassium ions out of the topsoil, altering soil chemistry and harming plants and soil organisms.

2. Acid precipitation also “mobilizes” toxic metal ions such as aluminum, zinc, mercury, and copper by chemically converting them from insoluble forms to soluble forms.

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3. When acidic water runs off from land, it affects streams, rivers, and lakes.

4. Besides altering natural ecosystems, acid precipitation damages crops, erodes stone buildings, and corrodes vehicles, causing billions of dollars in damage.

5. Because the pollutants leading to acid deposition can travel long distances, their effects may be felt far from their sources.

C. We are addressing acid deposition.

VI.

Indoor Air Quality 1. Indoor air generally contains higher concentrations of pollutants than outdoor air. As a result, the health impacts from indoor air pollution in workplaces, schools, and homes outweigh those from outdoor air pollution.

A. Burning fuel causes indoor air pollution in the developing world.

B. Cigarette smoke and radon are the primary indoor pollutants in industrialized nations.

1. Secondhand smoke has been found to cause many of the same problems as directly inhaled cigarette smoke.

2. After cigarette smoke, radon gas is the second leading cause of lung cancer in the developed world.

C. Many VOCs pollute indoor air.

1. VOCs are emitted in very small amounts.

2. The implications for human health of chronic exposure to VOCs are far from clear.

D. Living organisms can pollute.

1. The most widespread source of indoor air pollution in the developed world may be living organisms.

2. Microbes that induce allergic responses are thought to be a major cause of building-related illness, a sickness produced by indoor air pollution. a. When the cause of such an illness is a mystery, and when symptoms are general and nonspecific, the illness is often called sick-building syndrome.

E. We can enhance indoor air quality.

1. Using low-toxicity materials, monitoring air quality, keeping rooms 272 ..

clean, and providing adequate ventilation are the keys to alleviating indoor air pollution in most situations.

2. In the industrialized world, we can try to avoid cigarette smoke, limit our exposure to new plastics and treated wood, and restrict our contact with pesticides, cleaning fluids, and other toxic substances by keeping them in garages or outdoor sheds.

Key Terms acid deposition acid rain aerosols air pollutants air pollution atmosphere atmospheric deposition atmospheric pressure carbon monoxide catalytic converter chlorofluorocarbons (CFCs) Clean Air Act climate cold front convective circulation Coriolis effect criteria pollutant front halocarbons high-pressure system hurricanes indoor air pollution industrial smog inversion layer lead low-pressure system Montreal Protocol

nitrogen dioxide nitrogen oxides outdoor air pollution ozone-depleting substances ozone hole ozone layer particulate matter photochemical smog primary pollutant relative humidity residence time scrubbers secondary pollutant sick-building syndrome smog stratosphere sulfur dioxide temperature inversion tornadoes toxic air pollutant troposphere tropospheric ozone volatile organic compounds (VOCs) warm front weather

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Teaching Tips 1. The AirData website of the US Environmental Protection Agency (www.epa.gov/outdoor-air-quality-data) provides air pollution data for the entire United States and produces reports and maps using criteria that you specify. Air data are acquired from two EPA databases: Air Quality System (AQS) and National Emission Inventory (NEI).

Present students with air data from your region or ask them to retrieve data themselves. The database will generate tables showing the facilities within a state or a county that emit various particulates in the order of total amount of emissions.

2. Assign students to read papers about air pollution and environmental justice at the University of Michigan’s website (www.umich.edu/~snre492/cases.html).

You can have groups of students each choose a paper from the website that relates to air pollution. Have them read the paper and then do follow-up research to find out the current status of the problem. The groups can write reports, do poster projects, or do PowerPoint presentations to the class or an invited assembly.

Ask students to consider the following questions.

• What was the initial discovery?

• What was the source of the problem?

• What lawsuits have been filed? What were the outcomes?

• What health effects have been documented?

• What do you think can be done to prevent similar problems?

3. As a classroom demonstration or student assignment, go to Smog City at www.smogcity.com, developed by the Sacramento Metropolitan Air Quality Management District. Smog City is an interactive air pollution simulator that shows how population, environmental factors, and land use contribute to air pollution. Smog City allows the user to adjust these factors to see the effect on ground-level ozone formation. Ask students to consider the following questions: • Does one factor seem to affect smog formation more than others?

• How do weather variables affect smog formation?

• How does population affect smog formation?

• What can you do as an individual to reduce smog?

4. To find out about pollution in your community, go to Scorecard: The Pollution Information Site (www.scorecard.goodguide.com). Have students enter their ZIP codes to learn about toxic chemicals released into the air by local sources.

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5. Provide white or light-colored cotton squares to students for an outdoor activity that will answer this question: “Is there particulate matter in the atmosphere around campus that I am unable to see?” Be sure that all swatches are the same size. Ask students if they can predict where there might be higher levels of air quality impact. If in urban areas, regions near the ground that are subject to diesel fumes provide interesting collecting sites. If possible, leave the swatches outdoors secured to trees, posts, or even the building. Retrieve the material after 24 hours and examine the swatches against a control swatch kept inside the classroom in an airtight container. Ask students if any of their predictions match the visual results.

Additional Resources Websites 1. AIRNow, US Environmental Protection Agency (www.airnow.gov) This interagency and international website provides air quality forecasts, information, and reports on air quality to the general public.

2. Air topics, US Environmental Protection Agency (www.epa.gov/environmental-topics/air-topics) This resource has general information about air quality and regulation, including criteria on air pollutants, air quality trends, and toxic air pollution.

3. The Hubbard Brook Ecosystem Study, Hubbard Brook Research Station (www.hubbardbrook.org) The home page of the Hubbard Brook Ecosystem Study (HBES) provides access to its three main resources: Research and Data, Hubbard Brook Research Foundation, and Educational Resources.

Audiovisual Materials 1. Atmospheric Hole: The History of the Ozone Layer, 2006, distributed by Films for the Humanities and Sciences (www.films.com) This program shows how the ozone layer is depleted and how its depletion is stunting, mutating, and destroying life.

2. What’s Up with the Weather?, 2007, NOVA video, distributed by WGBH (Available on Amazon.com) This video examines today’s extreme weather patterns, such as flooding, hurricanes, and high temperatures. It explores whether these are natural phenomena or whether they are indicators of global warming.

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3. Heat, 2008, Frontline, PBS (www.pbs.org/wgbh/pages/frontline/heat) This video discusses air pollution in the context of ambient air pollution and greenhouse gases.

Weighing the Issues Smog-busting Solutions Facts to consider: This question most definitely requires a personal response, as each student’s local air quality is affected by some form of air pollution, no matter how minute. First, the student should address the issue from a personal perspective—has the student ever gotten an emissions test? Do they know where to get one? Could the student consume less fuel? If not, could subsidies help in this regard? Would the student consider a new, more environmentally responsible vehicle? Second, pursue the city’s approach to tackling air pollution. Start first with public transportation—is it available? Like Mexico City, are there restricted fuel types? How does one become aware of the city’s pollution level? Is this publicized? How? Then the student can address recommendations and the benefits and drawbacks to those recommendations.

How Safe Is Your Indoor Environment?

Facts to consider: This question requires an individual response, but responses should consider a wide range of potential sources of air pollution, as designated by the EPA. These sources include asbestos; biological pollutants such as mold, mildew, or pollen; carbon monoxide from gas appliances or woodstoves; formaldehyde used in building materials; organic chemicals used in cleaning products, dry cleaning, or hobbies; lead from old paint; nitrogen dioxide from gas or kerosene heaters; pesticides to control indoor insects or microorganisms; naturally occurring radon gas; combustion products from fireplaces or woodstoves; and secondhand smoke. General ways to make indoor spaces safer from pollution include limiting the use of plastics and treated wood where possible, increasing ventilation, having the space tested for radon gas, and storing cleansers and other household products in a garage or shed.

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The Science behind the Story Does Air Pollution Affect the Brain, as Well as the Lungs and the Heart?

Observation: Specifically, in Mexico City, metal-rich particulates from trash incinerators were peaking in the morning, whereas smoke from fires outside the city blew in during the afternoon. Most health impacts of urban pollution affect the respiratory system. Many studies have confirmed that Mexico City residents show reduced lung function in comparison with people from less-polluted areas and that respiratory problems become worse and emergency room visits become more numerous when pollution is severe.

Study: A research team led by Isabelle Romieu of Mexico’s National Institute of Public Health examined the effects of growing up amid polluted air. Her team measured lung function in 3,170 8-year-old children from 39 Mexico City schools across 3 years and correlated this with their exposure to tropospheric ozone, nitrogen dioxide, and particulate matter.

Another Mexican researcher, Lilian Calderón-Garcidueñas, has led several studies comparing chest x-ray films and medical records of Mexico City children with those of similar children from nonpolluted locations.

One Mexican research team analyzed the hearts of 21 people from Mexico City who had died at an early age.

Results: Romieu and her colleagues showed in a series of studies that the city’s pollution worsens asthma in children, particularly those with certain genetic profiles.

Calderón-Garcidueñas’s team found hyperinflation and other problems with the lungs of the Mexico City youth.

In hearts, scientists found that pollution exacts a toll before age 18.

Recent research shows that it can damage children’s brain tissue in ways similar to Alzheimer’s disease.

In one study using brain scans, Calderón-Garcidueñas and her colleagues found that 56% of Mexico City youth had lesions on the brain’s prefrontal cortex, whereas fewer than 8% did in a region with clean air.

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How Did Scientists Discover Ozone Depletion and Its Causes?

Observation: In 1974, American chemist F. Sherwood Rowland and his Mexican postdoctoral associate Mario Molina took note of all the preceding research and realized that CFCs were rising into the stratosphere, being broken down by UV radiation, and releasing chlorine atoms that ravaged the ozone layer.

Hypothesis: CFCs and other halocarbons were indeed depleting ozone.

Experiment: But why should an “ozone hole” be localized over Antarctica, of all places? And why only in the southern hemisphere’s spring? To determine what was causing this odd phenomenon, atmospheric chemists Susan Solomon, James Anderson, Paul Crutzen, and others mounted expeditions in 1986 and 1987 to analyze atmospheric gases using ground stations and high-altitude balloons and aircraft.

Results: From their data, they figured out that the region’s polar stratospheric clouds and circulating winds provided ideal conditions for chlorine from CFCs and other chemicals to set into motion the destruction of massive amounts of ozone.

Impacts: By 1987, the mass of scientific evidence helped convince the world’s nations to agree on the Montreal Protocol, which aimed to cut CFC production in half by 1998. Within 2 years, further scientific evidence and computer modeling showed that more drastic measures were needed. In 1990, the Montreal Protocol was strengthened to include a complete phase-out of CFCs by 2000, in the first of several follow-up agreements. Today, amounts of ozone-depleting substances in the stratosphere are beginning to level off. If all goes well, scientists expect full recovery at midlatitudes by midcentury, followed by full recovery in the polar regions one or two decades later.

Local Connections Go online and examine the maps and resources available at the EPA’s “AirNow” website at www.airnow.gov. What is the current status of the Air Quality Index in the place you live? How does it compare with the AQI in other regions in North America? Why do you think your region may be better or worse than others in its air quality? Now go to the EPA’s “AirCompare” website at https://www3.epa.gov/aircompare/, and compare your county with some other county that you think you might like to live in or visit. Describe one way in which pollution or health data for the two counties differs. Taking into account all you’ve learned in this chapter about sources of air pollutants and the conditions under which pollutants can drift or concentrate, what would you say are some reasons your region experiences certain kinds of pollution? Why might it avoid some types of pollution that other regions suffer?

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Class time: one class period or could be completed as a homework assignment.

This activity could be completed during class or as a homework assignment. After completing the assignment, the students could participate in a short discussion summarizing the information they collected.

Calculating Ecological Footprints Total NOx emissions (lb)

NOx emissions from vehicles (lb)

65.4

39.1

Your class

Answers will vary

Answers will vary

Your state

Answers will vary

Answers will vary

United States

21.4 billion

12.8 billion

You

1. The US population increase from 2014 to 2040 is projected to be 21.6%. NOx emissions have decreased during the past decade, even as the population has grown, largely the result of improved technology. Unless unexpected technological breakthroughs occur, or unless fuel demand surges, we may expect these trends to continue.

2. The average American driver emits 39.1 pounds of NOx from their vehicle. By cutting the miles you drive in half, 19.55 pounds of NOx emissions could be avoided, which would be a 29.9% reduction in your total NOx emissions.

3. Answers will vary. Anything that would reduce your combustion of fossil fuels would also reduce your amount of NOx emissions (e.g., setting your thermostat lower in the winter and higher in the summer; turning off unnecessary lights; taking cooler, shorter showers). Reducing the per capita share of vehicle miles traveled is as easy as carpooling, combining several errands into one trip, or walking/biking when possible.

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18 Global Climate Change Chapter Objectives This chapter will help students: Describe Earth’s climate system and explain the factors that influence the global climate Identify greenhouse gases and characterize human influences on the atmosphere and on climate Summarize how researchers study climate Outline current and expected future trends and impacts of climate change in the United States and around the world Suggest and assess ways in which we may respond to climate change

Lecture Outline I.

Central Case Study: Rising Seas Threaten South Florida A. By 2030, flooding is predicted to strike Miami and Miami Beach about 45 times per year—becoming no longer a curious inconvenience but an existential threat.

B. Rising sea levels are driven by global climate change.

C. The world’s oceans rose 20 cm (8 inches) in the 20th century as warming temperatures expanded the volume of seawater and caused glaciers and ice sheets to melt, discharging water into the oceans. These processes are accelerating today, and scientists predict that the sea level will rise another 26–98 cm (10–39 inches) or more in this century as climate change intensifies.

D. As sea levels rise, coastal cities across the globe—from Venice to Amsterdam to New York to San Francisco—are facing challenges.

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E. South Florida is highly sensitive to sea-level change because its landscape is exceptionally flat; just 1 meter of sea-level rise would inundate more than a third of the region. A 4-m (13-ft) rise in sea level would submerge Miami and reduce the region to a handful of small islands.

F. The porous limestone bedrock that underlies South Florida also poses a challenge.

G. Moreover, as salt water moves inland, it contaminates the fresh drinking water of South Florida’s Biscayne Aquifer.

II.

Our Dynamic Climate A. What is climate change?

1. Climate describes an area’s long-term atmospheric conditions, including temperature, precipitation, wind, humidity, barometric pressure, solar radiation, and other characteristics.

2. Global climate change—generally referred to simply as climate change—describes an array of changes in aspects of Earth’s climate, such as temperature, precipitation, and the frequency and intensity of storms. People often use the term global warming synonymously in casual conversation, but global warming refers specifically to an increase in Earth’s average surface temperature.

B. Three factors influence climate.

1. The first is the sun, the second is the atmosphere, and the third is the oceans.

C. Greenhouse gases warm the lower atmosphere.

1. As Earth’s surface absorbs solar radiation, the surface increases in temperature and emits infrared radiation. Some atmospheric gases absorb infrared radiation and are known as greenhouse gases.

After absorbing radiation emitted from the Earth’s surface, greenhouse gases reemit infrared radiation. Some of this reemitted energy is lost to space, but much of it travels back downward, warming the lower atmosphere and the surface in a phenomenon known as the greenhouse effect.

D. Greenhouse gas concentrations are rising fast.

1. The greenhouse effect is a natural phenomenon, and greenhouse gases have been present in our atmosphere throughout Earth’s history.

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2. We have boosted Earth’s atmospheric concentration of carbon dioxide from roughly 278 parts per million (ppm) in the late 1700s to more than 400 ppm today.

3. The sudden influx of carbon from the lithosphere into the atmosphere is the main reason atmospheric carbon dioxide concentrations have increased so dramatically.

4. When we clear forests, we reduce the biosphere’s ability to remove carbon dioxide from the atmosphere.

5. Methane concentrations are 2.5 times higher than in 1750—and today’s atmospheric concentration is the highest by far in more than 800,000 years.

6. Human activities have also elevated the atmospheric concentrations of nitrous oxide.

7. Among other greenhouse gases, ozone concentrations in the troposphere have risen more than 40% since 1750, a result of photochemical smog.

8. Water vapor is the most abundant greenhouse gas in our atmosphere and contributes most to the natural greenhouse effect.

E. Various factors warm or cool the surface.

1. Aerosols are microscopic droplets and particles that can have either a warming or a cooling effect. Soot particles, or “black carbon aerosols,” generally cause warming by absorbing solar energy, but most other aerosols cool the atmosphere by reflecting the sun’s rays.

2. To measure the degree of impact that a given factor exerts on Earth’s temperature, scientists calculate its radiative forcing—the amount of change in thermal energy that the factor causes.

3. Feedback complicates our predictions.

F. Climate varies naturally for several reasons.

1. Over thousands of years, our planet wobbles on its axis, varies in the tilt of its axis, and experiences change in the shape of its orbit, all in regular long-term cycles of different lengths. These variations, known as Milankovitch cycles, alter the way solar radiation is distributed over Earth’s surface.

2. The sun varies in the amount of radiation it emits over short and long time scales. This is referred to as solar output.

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3. The oceans hold 50 times more carbon than the atmosphere holds.

4. Oceanic circulation also shapes climate.

III.

Studying Climate Change A. Direct measurements tell us about the present.

B. Proxy indicators tell us about the past.

1. Evidence about paleoclimate, climate in the ancient past, is vital for giving us a baseline against which we can measure changes happening in our climate today. Proxy indicators are types of indirect evidence that serve as proxies, or substitutes, for direct measurement.

2. Ice caps, ice sheets, and glaciers have preserved tiny bubbles of ancient atmosphere.

3. Sediment beds beneath bodies of water can be analyzed to learn about the ancient vegetation in an area and, by extension, what the climate was like at the time.

4. Other proxy indicators include tree rings, packrat middens, and coral reefs.

C. Models help us predict the future.

1. Climate models are programs that combine what is known about atmospheric circulation, ocean circulation, atmosphere-ocean interactions, and feedback cycles to simulate climate dynamics.

IV.

Impacts of Climate Change A. Scientific evidence for climate change is extensive.

1. The Intergovernmental Panel on Climate Change (IPCC), which consists of many hundreds of scientists and governmental representatives, makes growing research knowledge accessible to policymakers and the public.

2. In 2013 and 2014, the IPCC released its Fifth Assessment Report.

B. Temperatures continue to rise.

1. Average surface temperatures on Earth have risen by about 1.1°C (2.0°F) in the past 100 years.

2. Polar regions will continue to experience the most intense warming.

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C. Precipitation is changing.

1. Some areas are receiving more rain and snow than usual while others are receiving less.

2. Future changes in precipitation are predicted to intensify regional changes that have already occurred. Many wet regions will receive more rainfall, increasing the risk of flooding, whereas many dry regions will become drier, worsening water shortages.

D. Extreme weather is becoming “the new normal.”

1. Data summarized by the U.S. Climate Extremes Index confirm that the frequency of extreme weather events in the United States has tripled since 1970.

2. Warm water fuels hurricanes, so with ocean temperatures rising, hurricanes are able to draw more energy from the ocean.

E. Melting ice has far-reaching effects.

1. Between 1980 and 2018, the World Glacier Monitoring Service estimates that the world’s glaciers on average have each lost thickness equivalent to more than 26 m (85 ft) in vertical height of water.

2. Mountains accumulate snow in winter and release meltwater gradually during summer.

3. Warming temperatures are also melting vast amounts of polar ice.

4. One reason warming is accelerating in the Arctic is that as snow and ice melt, darker, less reflective surfaces (such as bare ground and pools of meltwater) are exposed, and Earth’s albedo, or capacity to reflect light, decreases.

5. As Arctic Sea ice disappears, new shipping lanes are opening for commerce, and governments and companies are rushing to exploit newly accessible underwater oil and mineral reserves.

6. Warmer temperatures in the Arctic are also causing permafrost (permanently frozen ground) to thaw.

F. Rising sea levels may affect hundreds of millions of people.

1. As glaciers and ice sheets melt, increased runoff into the oceans causes sea levels to rise.

2. Higher sea levels lead to beach erosion, coastal flooding, the intrusion of salt water into aquifers, and greater impacts from storm surges.

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3. Whether sea levels this century rise 26 cm, 1 meter, or more, hundreds of millions of people will be displaced or will need to invest in costly efforts to protect against high tides and storm surges.

G. Acidifying oceans imperil marine life.

1. So far, the oceans have absorbed roughly one-quarter of the CO2 we have added to the atmosphere. This is altering ocean chemistry, making seawater more acidic—a phenomenon referred to as ocean acidification.

H. Organisms and ecosystems are affected.

1. Organisms are adapted to their environments, so changes to those environments affect them.

2. The IPCC has estimated that climate change could threaten as many as 20–30% of all plant and animal species with extinction.

3. The effects on plant communities make up an important component of climate change because by drawing in CO2 for photosynthesis, plants act as reservoirs for carbon.

4. In regions where precipitation and stream flow increase, erosion and flooding could pollute and alter aquatic systems.

I. Farms and forests experience a mix of consequences.

1. Large-scale experiments are showing that extra CO2 can both augment and diminish plant growth.

J. Climate change affects our health, wealth, and security.

1. Health—A warmer climate exposes us to a variety of health risks including heat stress, respiratory ailments from photochemical smog, the expansion of tropical diseases, disease from overflowing sewers after flooding, and injuries and drowning from worsening storms.

2. Wealth—Economists have tried to quantify the damages from climate change by totaling up its various external costs. Their estimates for the social cost of carbon, the economic cost of damages resulting from each ton of carbon dioxide we emit, run the gamut from $10 to $350 per ton, depending on what costs are included and what discount rate is used.

3. National Security—The many costs and impacts of climate disruption are beginning to endanger the ability of nations to ensure social stability and protect their citizens from harm. The Pentagon, the White House, the U.S. Navy, the Council on Foreign Relations, and the Central Intelligence Agency have all concluded and 285 ..

publicly reported that climate change is contributing to political violence, war and revolution, humanitarian disasters, and refugee crises.

K. Impacts will be significant in the United States.

1. Temperatures have risen 1.0°C since 1901 and will rise by another 1.4°C by 2050.

2. Impacts will vary by region, with each region facing its own challenges.

L. What is behind the political debate over climate change?

1. Scientists agree that today’s global warming is a result of the welldocumented recent increase in greenhouse gas concentrations in our atmosphere.

2. Yet despite the overwhelming evidence for climate change and its impacts, many people, especially in the United States, have long tried to deny that it is happening.

3. The views of climate change deniers have long been amplified by the mainstream American news media, which traditionally have sought to present two sides to every issue, even when the arguments of the two sides were not equally supported by evidence.

V.

Responding to Climate Change A. Society can respond in two ways.

1. We can respond to climate change in two fundamental ways. a. One is to pursue actions that reduce greenhouse gas emissions to lessen the severity of climate change. This strategy is called mitigation because the aim is to mitigate the problem, that is, to alleviate it or reduce its severity. b. The second type of response is to pursue strategies to cushion ourselves from the impacts of climate change. This strategy is called adaptation because the goal is to adapt to change.

2. Both adaptation and mitigation are necessary.

B. What can each of us do?

1. How you get around—Transportation accounts for 35% of U.S. CO2 emissions. If you drive less or live without a car, you will cut down greatly on your carbon footprint.

2. How you power up—Electricity accounts for 35% of U.S. emissions. To save electricity, buy energy-saving products.

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3. What you eat—Scientists estimate that animal agriculture accounts for 14.5% of the world’s greenhouse gas emissions. Eating a vegetarian or vegan diet greatly reduces the emissions for which you are responsible.

4. What you do—There are many additional steps you can take to minimize your carbon footprint.

C. A new generation is pressing for action.

1. Many young people are finding their voices through a growing global protest movement sparked by Swedish teenager Greta Thunberg.

D. Multiple strategies can help us reduce emissions.

1. Conservation and efficiency 2. While our society begins to transition to clean and renewable alternatives, we are also trying to capture emissions before they leak to the atmosphere. i. Carbon capture and storage refers to technologies or approaches that remove carbon dioxide from emissions and then store it below ground under pressure in deep salt mines, depleted oil and gas deposits, or other underground reservoirs.

3. The Drawdown Project—This plan proposes 100 strategies that, if implemented, would bring us to a drawdown point at which atmospheric greenhouse gases peak and begin to decline.

E. What role should government play?

1. Should it mandate change through laws and regulations? Should it impose no policies at all and hope that private enterprise will develop solutions on its own? Should it take the middle ground and design policies that give private entities financial incentives to reduce emissions?

2. In 2009, the House of Representatives passed legislation to create a cap-and-trade system in which industries and utilities would compete to reduce emissions for financial gain.

F. We can put a price on carbon.

1. Carbon pricing strategies are intended to compensate the public for the external costs that we all suffer from fossil fuel emissions and climate change.

2. Carbon pricing lifts the burden of paying for these impacts off the shoulders of the public and shifts it to the entities responsible for emissions.

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3. Carbon emissions can be taxed. a. Critics of cap-and-trade systems would prefer that governments enact a carbon tax instead. A carbon tax is a type of green tax on the emission of carbon dioxide or on the carbon content of fossil fuels. b. The downside of a carbon tax is that polluters pass the cost along to consumers by charging higher prices for the products or services that they sell. Proponents of carbon taxes have responded by proposing an approach called carbon fee and dividend. In this approach, funds that the government receives from polluters through the carbon tax, or “fee,” are transferred as a tax refund, or “dividend,” to taxpayers. The carbon fee and dividend approach is a type of revenue-neutral carbon tax, because there is no net transfer of revenue from taxpayers to the government. For this reason, the approach is gaining broad political appeal.

4. Carbon trading uses markets. a. A carbon trading system is one in which permits are traded for the emission of carbon dioxide.

G. International climate negotiations have sought to limit emissions.

1. Reaching consensus among 200 nations through the treaty process is a daunting challenge.

2. In 1992, most of the world’s nations signed the United Nations Framework Convention on Climate Change (FCCC). This treaty outlined a plan for reducing greenhouse gas emissions to 1990 levels by the year 2000 through a voluntary approach.

3. Emissions kept rising, however, so nations forged a binding agreement to require emissions reductions. An outgrowth of the FCCC drafted in 1997 in Kyoto, Japan, the Kyoto Protocol mandated signatory nations, by the period 2008–2012, to reduce emissions of six greenhouse gases to levels below those of 1990.

4. The United States was the only developed nation not to ratify the Kyoto Protocol.

H. The Paris Agreement produced global consensus.

1. In the Paris Agreement, 197 nations declared a joint goal to limit global temperature rise to 2.0°C (3.6°F) above pre-industrial levels and to attempt to keep the rise below 1.5°C (2.7°F).

2. In 2017, President Trump announced that his administration would withdraw the United States from the Paris Agreement.

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3. The Paris Agreement will ultimately be judged by how well nations live up to their pledges.

I. Will emissions cuts hurt the economy?

1. Many U.S. policymakers have opposed mandates to reduce emissions because of fears that this will hamper economic growth.

2. Because resource use and per capita emissions are high in the United States, policymakers and industries often assume that the United States has more to lose economically from restrictions on emissions than developing nations do.

3. Germany, Japan, and China have realized that instead they can gain from inventing and developing new technologies and are now leading the world in the production, deployment, and sales of solar energy technology.

J. States and cities are advancing climate change policy.

1. Mayors from more than 1,000 cities have signed on to the US Mayors Climate Protection Agreement, committing their cities to pursue policies to “meet or beat” Kyoto Protocol guidelines.

2. A number of US states have enacted targets or mandates for renewable energy production, seeking to boost cleaner alternatives to fossil fuels.

3. Carbon pricing programs generally allow emitters to buy carbon offsets, voluntary payments intended to enable another entity to help reduce the emissions that one entity is unable to reduce.

4. Carbon offsets are popular among utilities, businesses, universities, governments, and individuals trying to achieve carbon neutrality, a condition in which no net carbon is emitted.

K. Should we engineer the climate?

1. As climate disruption becomes more severe, some scientists and engineers are reluctantly considering drastic, assertive steps to alter Earth’s climate in a last-ditch attempt to reverse global warming— an approach called geoengineering.

L. We can all address climate change.

1. Just as we each have an ecological footprint, we each have a carbon footprint that expresses the amount of carbon we are responsible for emitting.

2. Global climate change may be the biggest challenge we face, but halting it would be our biggest victory.

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Key Terms adaptation aerosols cap and trade carbon capture and storage carbon footprint carbon neutrality carbon offsets carbon pricing carbon tax carbon trading climate climate change climate models fee and dividend geoengineering global climate change

global warming greenhouse effect greenhouse gases Intergovernmental Panel on Climate Change (IPCC) Kyoto Protocol Milankovitch cycles mitigation ocean acidification paleoclimate proxy indicators radiative forcing revenue-neutral carbon tax social cost of carbon United Nations Framework Convention on Climate Change (FCCC)

Teaching Tips 1. Provide students with detailed information about paleoclimate proxy data by visiting the National Oceanic and Atmospheric Administration (NOAA) Paleoclimatology Program website (www.ncdc.noaa.gov/paleo/slides.html).

There are online slide sets with photographs of field research, important datasets, and descriptive diagrams appropriate for college-level courses. The available slide sets for paleoclimatology are The Ice Ages, Climate and the Classic Maya Civilization, Coral Paleoclimatology, Polar Ice Cores, Packrat Middens, Tree Rings, Heinrich Events, and Low Latitude Ice Cores. A ninth set, Rock Varnish, is available only as 35-mm slides at this time, but may be online in the near future. Have groups of students create either a poster or a PowerPoint presentation about the above topics. You may want to include the study of fossil pollen from core samples. NOAA’s website (www.ncdc.noaa.gov/paleo/ctl/glossary.html) provides an excellent glossary of climate terms as well as an overview of a climate timeline.

2. Energy Star (www.energystar.gov) is a government-backed program helping businesses and individuals protect the environment through superior energy efficiency.

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There are home and business products in more than 40 categories eligible for the Energy Star designation. In general, these products use less energy, cost less money to operate, and protect the environment. Ask students to choose a product. Assign them to search the Energy Star website for the criteria required for that product, and ask them to share that information with the class.

3. Have students learn more about how tree-ring research helps us to understand ancient climates, fire ecology, the activities and impacts of early humans, global warming, and many other topics. The Laboratory of Tree-Ring Research (www.ltrr.arizona.edu) has online lessons about tree-ring basics and a tutorial called Try Crossdating Yourself, which teaches students how scientists match and crossdate tree rings from samples in both local and wideranging areas to gather information about small events (for example, a local insect infestation) and large ones (such as a severe drought). There are a series of online exercises that can be printed out and used as homework or as lab exercises. There are also numerous links to research publications and subtopics such as dendroecology and dendroclimatology.

4. Ask students to examine statements from their power company, surveying several months of data, if possible. Answer the following questions.

• Is there a difference in the kilowatt hours used from one month to the next?

• If there is a difference, what are some reasons for the differences?

• Ask students to predict which appliance, system, or activity in their homes accounts for the most power use.

Invite a representative from a local utility to visit the classroom if that utility offers a free home energy audit. Have the guest speaker explain the benefits of a home energy audit and allow students to ask questions and perhaps schedule an audit for their dorm, home, or apartment.

5. A common decision instructors face is how much material to present to students for a particular course. When faced with a wide range of possible topics, instructors can be tempted to include as many topics as possible in as much depth as possible, which may result in a low level of student understanding and retention, and hence, low exam grades.

Extensive research has investigated how people learn “chunks” of data in a discipline, examining the differences between learning while a novice and learning once a more expert status is attained, and how different types of learners make the mental connections to allow broader associations to form larger chunks of data. The research shows that it is possible for most people to take in somewhere between 3–7 new chunks of data at one time, with five usually being the optimal number. The size of these chunks differs greatly, however, between novices and experts. For example, a novice chunk might be a single new definition, whereas an expert chunk could be an entire concept 291 ..

built around that already well-understood definition plus three others.

The take-home message for instructors is to first determine the amount of information that forms a “chunk” for your students and then to prepare a lesson with about 3–5 of these chunks—certainly never more than seven–in a single day, with some way to review those bits of information before going on to the next lesson.

Additional Resources Websites 1. Climate Change Research, US Environmental Protection Agency (EPA) (www.epa.gov/climate-research ) This website has national and international information about climate, greenhouse emissions, potential impacts, actions, and links to other resources.

2. Global Warming, Earth Observatory, National Aeronautics and Space Administration (NASA) (earthobservatory.nasa.gov) This NASA web reference site gives basic information about global warming, summarizes the skeptics’ point of view, and describes NASA’s global climate change projects.

3. Intergovernmental Panel on Climate Change, The United Nations Environment Program (UNEP) and World Meteorological Organization (WMO) (www.ipcc.ch) The official IPCC website has information about IPCC and its activities, publications, press releases, and official documents.

4. Climate Prediction Center, The National Weather Service (NWS), NOAA, US Department of Commerce (www.cpc.ncep.noaa.gov) This part of the National Weather Service website is dedicated to presenting climate data, models, and statistical analyses to predict future climate trends.

Audiovisual Materials 1. Rising Waters: Global Warming and the Fate of the Pacific Islands, 2000, produced by the Independent Television Service and Pacific Islanders in Communications, distributed by Bullfrog Films (www.bullfrogfilms.com) This video examines the problem of global climate change by showcasing the personal stories of Pacific Islanders.

2. Be Prepared for Global Warming, 2003, distributed by Films for the Humanities & Sciences (www.films.com) 292 ..

This program examines how land and populations made vulnerable by rapidly rising worldwide temperatures are protected.

3. The Impact of Global Warming, 2000, distributed by Films for the Humanities & Sciences (www.films.com) This program travels the world to observe how global warming, accelerated and exacerbated by air pollution, is affecting society.

4. An Inconvenient Truth: A Global Warning, 2006, 96 minutes, PG. An Academy Award–winning film by former US Vice President Al Gore. (www.takepart.com/ait10) A compelling view of the future of planet Earth—and human civilization.

Touted as a wake-up call that cuts through the myths and misconceptions to show that global warming is a real and present danger, the film brings home Al Gore’s message that we must act now to save Earth. In end-of-term class surveys, after several terms of showing this film, students have rated it as one of the most important experiences they’ve taken away from the class. It is important to allow students to decompress and debrief after viewing this film.

5. Before the Flood, 2016, 96 minutes, Distributed by National Geographic (www.beforetheflood.com) This film explores the science and politics of climate change across the globe, including how average citizens can be a positive force for change.

Weighing the Issues Carbon Tax or Cap and Trade?

Facts to consider: Responses to these questions will vary. First, the definitions of cap and trade and carbon tax are important. In a cap-and-trade system, government first sets an overall cap on emissions. As polluting facilities respond, some will have better success reducing emissions than others. For example, Plant A succeeds in cutting its emissions well below the cap, whereas Plant B fails to cut its emissions at all. As a result, Plant B pays money to Plant A to purchase allowances that Plant A is no longer using. Plant A profits from this sale, and the government cap is met, reducing pollution overall. Over time, the cap can be progressively lowered to achieve further emissions cuts. With a carbon tax, governments charge polluters a fee for each unit of greenhouse gases they emit.

This gives polluters a financial incentive to reduce emissions. Also necessary is the definition of a fee-and-dividend program. In this approach, funds from the carbon tax, or “fee,” paid to government by polluters are transferred as a tax refund, or “dividend,” to taxpayers.

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Taking Climate Change to Court Facts to consider: This question will require an individual response. However, consideration must be given to the different approaches to righting environmental wrongs. One approach would be to be proactive—setting limits on greenhouse gases, for example, such as we limit the speeds on the roads we travel. Just as it is hoped that this limit will reduce the number of fatal crashes, a limit on greenhouse gases could help us avoid a long-term problem or reduce its potential severity. Or we could be reactive and penalize individuals, corporations, or governments once the wrong has been committed and identified and a party can be blamed. This seems more complex and does nothing to avoid the damaging situation. This is akin to a carbon tax—pollute what you want, but you will have to pay for it. In the case of a lawsuit, this is perhaps even more vague because the parties will only have to pay if it is proven that they are to blame. Also, how do you quantify the damages? Calculating external costs is difficult enough—it is unknown whether an adequate settlement could ever be reached.

The Science behind the Story What Can We Learn From the World’s Longest Ice Core?

Observation: The ice sheets of Antarctica and Greenland trap tiny air bubbles, dust particles, and other proxy indicators of past conditions. By drilling boreholes and extracting ice cores, researchers can tap into these priceless archives. From 2005 to 2008, five follow-up papers in the journals Science and Nature reported analyses of greenhouse gas concentrations from the European Project for Ice Coring in Antarctica (EPICA) ice core and extended the gas and temperature data back to cover the past 800,000 years.

Hypothesis: Researchers could quantify atmospheric concentrations of carbon dioxide and methane.

Results: These data show that our emission of these greenhouse gases since the Industrial Revolution has brought their atmospheric concentrations well above the highest levels that they had reached naturally at any time in the previous 800,000 years. The EPICA results also confirm that temperature swings in the past were tightly correlated with concentrations of greenhouse gases.

Implication: The clear relationship between greenhouse gases and temperature evident in the EPICA data suggests that if we want to prevent sudden global warming, we will need to reduce our society’s greenhouse emissions.

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Why and How Does Global Warming Lead to Extreme Weather Events?

Observation: As Earth has gotten hotter, extreme weather events have become more frequent and more severe.

Question: Is climate change causing this increase in extreme weather events? If so, what is the mechanism?

Study: High above Canada, a strong current of air that encircles the globe—a jet stream—blows through the upper troposphere and lower stratosphere, from west to east. Another jet stream blows across Mexico and the southern tier of U.S. states.

In North America, most weather systems move from west to east, influenced by the jet streams. A relatively straight and fast-blowing jet stream allows weather systems to move through quickly. A slower jet stream, however, bends widely to and fro, like a slow-moving river. As it meanders north and south, its looping curves can stall weather systems by blocking their movement in what is called an atmospheric blocking pattern. In 2012, Jennifer Francis and Stephen Vavrus proposed that this blocking pattern may be why global warming is leading to more extreme weather. They explained that when the jet stream moves slowly, it gets stuck in a north-south orientation for long periods of time, which prevents weather events from moving west to east as they normally would.

Results: Blocking patterns have been associated with numerous extreme weather events, including Superstorm Sandy, droughts, and even extreme cold events.

Local Connections How might your campus reduce its greenhouse gas emissions? Come up with three specific proposals for ways to reduce emissions on your campus that you feel would be effective and feasible. How would you present these proposals to campus administrators to gain their support?

Class time: one or more class periods.

This activity could be used as a larger project. Students could develop their proposals in class and, depending on your school, they could present them to the campus administrators or campus sustainability officers.

As students are working on this project, be sure they are considering the feasibility of their proposals. For example, how will it be funded? Does it require a significant systemic change? Does it require infrastructure change? Will it require buy-in from the entire campus community or a small fraction of it? Etc.

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Calculating Ecological Footprints Carbon footprint (tons per person per year) World average

4.5

US average

16

Your footprint

Answers will vary

Your footprint with three changes (see Question 3)

Answers will vary

1. Answers will vary. Students may have larger or smaller footprints than the average US resident, but most will have substantially larger footprints than the average person in the world. The consumption-intensive North American lifestyle accounts for this, particularly our auto transportation, electrical use, air travel, and industrialized agriculture.

2. Answers will vary. Changes in the choice of a place to live and auto and jet travel will make relatively large differences.

3. Answers will vary depending on the changes.

4. Answers will vary. The choice to purchase carbon offsets is up to the student.

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19 Fossil Fuels and Energy Efficiency Chapter Objectives This chapter will help students: Identify the energy sources we use Discuss the value of the EROI concept Describe the formation of major types of fossil fuels Explain how we extract, process, and use fossil fuels Assess concerns over the future decline of conventional oil supplies Outline ways in which we are extending our reach for fossil fuels Examine environmental impacts of fossil fuel use, and explore ways to minimize these impacts Assess the political, social, and economic aspects of fossil fuel use Discuss strategies for conserving energy and enhancing efficiency

Lecture Outline I.

Central Case Study: Alberta’s Oil Sands and the Keystone XL Pipeline A. Everything relating to Canada’s oil sands is huge.

B. Oil sands, also called tar sands, are layers of sand or clay saturated with a viscous, tarry type of petroleum called bitumen.

C. Extracting oil from oil sands is extremely detrimental to the environment.

D. Thanks to the oil sands, Canada boasts the world’s third-largest proven reserves of oil, after Venezuela and Saudi Arabia.

E. Canada looked for buyers south of its border first, and the TransCanada 297 ..

Corporation built the Keystone Pipeline to ship diluted bitumen into the United States.

F. The Keystone XL pipeline proposal soon met opposition from people living along the proposed route who were concerned about health, environmental protection, and property rights.

G. Pipeline proponents argued that the Keystone XL project would create jobs for workers in the US heartland and would guarantee a dependable oil supply for decades to come.

H. Opponents of the pipeline extension expressed dismay at the destruction of boreal forest and anxiety about transporting oil above the continent’s largest aquifer, where spills could contaminate drinking water for millions of people and irrigation water for America’s breadbasket.

I. In November 2015, President Obama decided against approving the Keystone XL pipeline and told the nation that his administration had judged that the pipeline “would not serve the national interest of the United States.”

J. Obama’s decision on Keystone XL did not end the broader debate over the role of fossil fuels in our economy.

II.

Sources of Energy A. Nature offers us a variety of energy sources.

1. Most of Earth’s energy comes from the sun. a. We can harness energy from the sun’s radiation directly. b. Solar radiation also helps drive wind and the water cycle, enabling us to harness wind power and hydroelectric power. c. Sunlight drives photosynthesis and the growth of plants. d. When plants and other organisms die and are buried in sediments under particular conditions, their stored chemical energy may eventually be incorporated into fossil fuels, which are highly combustible substances formed from the remains of organisms from past geological ages.

2. A great deal of energy emanates from Earth’s core, making geothermal power available for our use.

3. Energy sources such as sunlight, geothermal energy, and tidal energy are considered perpetually renewable because they are readily replenished, so we can keep using them without depleting them. In contrast, energy sources such as coal, oil, and natural gas are considered nonrenewable.

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B. We rely mostly on fossil fuels.

1. We have favored fossil fuels as an energy source because their high energy content makes them efficient to burn, ship, and store.

2. We use these fuels for transportation, manufacturing, heating, and cooking and also to generate electricity, a secondary form of energy that is convenient to transfer over long distances and apply to a variety of uses.

C. It takes energy to make energy.

1. Net energy expresses the difference between energy returned and energy invested.

2. When we assess energy sources, it is useful to use a ratio often denoted as EROI—energy returned on investment. EROI ratios are calculated as follows: EROI = Energy returned/Energy invested.

D. Where will we turn for energy?

III.

Fossil Fuels: Their Formation, Extraction, and Use A. Fossil fuels are formed from ancient organic matter.

1. The fuels we burn today in our vehicles, homes, industries, and power plants were formed from the tissues of organisms that lived 100–500 million years ago.

2. Fossil fuels are formed only when organic material is broken down in an anaerobic environment—one that has little or no oxygen.

3. Coal is a hard blackish substance formed from organic matter compressed under very high pressure, creating dense, solid carbon structures.

4. The thick blackish liquid we know as oil consists of many types of hydrocarbon molecules. The term crude oil refers specifically to oil extracted from the ground before it is refined. Natural gas is a gas consisting primarily of methane (CH4) and lesser, variable amounts of other volatile hydrocarbons. Oil is also known as petroleum, although this term is commonly used to refer to oil and natural gas collectively.

5. Oil sands consist of moist sand and clay containing 1–20% bitumen, a thick and heavy form of petroleum that is rich in carbon and poor in hydrogen.

6. Oil shale is sedimentary rock filled with organic matter that can be processed into a liquid form of petroleum called shale oil.

7. Methane hydrate is an ice-like solid consisting of molecules of methane embedded in a crystal lattice of water molecules.

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B. Economics determines how much will be extracted.

1. The amount of a fossil fuel that is technologically and economically feasible to remove under current conditions is termed its proven recoverable reserve.

C. Refining results in a diversity of fuels.

1. Through the process of refining, hydrocarbon molecules are separated by size and are chemically transformed to create specialized fuels for heating, cooking, and transportation, and to create lubricating oils, asphalts, and the precursors of plastics and other petrochemical products.

D. Fossil fuels have many uses.

1. Today, we burn coal largely to generate electricity.

2. Like coal, natural gas is used to generate electricity in power plants as well as to heat and cook in our homes, among many other uses.

3. Most oil is used as fuel for vehicles, including gasoline for cars, diesel for trucks, and jet fuel for airplanes. Fewer homes burn oil for heating these days, but industry and manufacturing continue to use a great deal.

E. We are depleting fossil fuel reserves.

1. To assess how long this remaining oil will last, analysts calculate the reserves-to-production ratio, or R/P ratio, by dividing the amount of total remaining reserves by the annual rate of “production” (i.e., extraction and processing).

2. Eventually, however, the extraction of any nonrenewable resource will come to a peak and then decline. In general, extraction tends to decline once reserves are depleted halfway. If demand for the resource holds steady or rises while extraction declines, a shortage will result. With oil, this scenario has come to be nicknamed peak oil.

F. Peak oil will pose challenges.

1. The peak in extraction came to be known as Hubbert’s peak.

2. Discovery or development of wholly new sources of oil can delay the peak by boosting our overall proven reserves.

3. Predicting an exact date for peak oil is difficult.

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IV.

Reaching Further for Fossil Fuels A. Mountaintop mining extends our reach for coal.

1. Coal mining has long been an economic mainstay of the Appalachian region, but mountaintop removal mining has brought coal extraction to a whole new level. In this method, entire mountaintops are blasted away to access coal seams running through them.

B. Secondary extraction yields additional fuel.

C. Directional drilling reaches more fuel with less impact.

1. Today’s directional drilling technology allows drillers to bore down vertically and then curve to drill horizontally.

D. Hydraulic fracturing expands our access to oil and gas.

1. Hydraulic fracturing (also called fracking) involves pumping chemically treated water under high pressure into deep layers of rock to crack them. Sand or small glass beads are injected to hold the cracks open as the water is withdrawn. Gas or oil then travels upward, with pressure and pumping, through the newly created system of fractures.

E. We are drilling farther offshore.

F. Melting ice is opening the Arctic.

G. We are exploiting new fossil fuel sources.

V.

Addressing Impacts of Fossil Fuel Use A. The extraction of fossil fuels has many environmental impacts.

1. The mining of coal has a substantial impact on natural systems and human well-being.

2. The extensive infrastructure needed to support a full-scale drilling operation typically includes access roads, transport pipelines, housing for workers, waste piles for excavated soil, and ponds to collect toxic sludge. These tend to pollute the soil, air, and water; fragment habitats; and disturb wildlife. These impacts can be readily seen at most drilling sites and have been particularly well documented on the Alaskan tundra, where policymakers continue to debate whether to open the Arctic National Wildlife Refuge to drilling.

3. Extracting oil or natural gas by means of hydraulic fracturing exerts all the impacts of conventional drilling while also posing additional concerns.

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4. Impacts from the extraction of oil sands surpass those of conventional fossil fuel extraction.

B. Fuels can leak during transport.

1. Once mined, coal is generally transported by rail in open cars, which releases coal dust into the air. Oil is also transported by rail, in pressurized tank cars.

2. Oil is commonly conveyed by pipelines, and pipelines are subject to corrosion, vandalism, and equipment malfunction, any of which can result in spills that contaminate soil and water.

3. Oil is transported in pressurized tank cars, which can explode if they derail.

4. Any time natural gas leaks into the air, its main component, methane, is added to the atmosphere. A great deal of methane also escapes to the atmosphere from oil drilling sites, where gas accompanying an oil deposit is released to the air because pipelines for the gas do not exist.

5. Of the many ways in which fossil fuels can pollute water, what comes to mind first for most people is how oil spilled from tanker ships or drilling platforms can foul coastal waters and beaches.

C. Fossil fuel emissions also pose health risks.

1. Besides modifying our climate, fossil fuel emissions affect human health.

D. Clean coal technologies aim to reduce air pollution from coal.

1. Clean coal technologies refer to an array of techniques, equipment, and approaches that aim to remove chemical contaminants during the generation of electricity from coal.

E. Carbon emissions drive climate change.

1. Carbon dioxide is a greenhouse gas, and CO2 released from fossil fuel combustion warms our planet and drives changes in the global climate.

2. Methane is also a potent greenhouse gas that drives climate warming.

F. Can we capture and store carbon?

1. Many current efforts focus on carbon capture and storage. This

approach involves capturing carbon dioxide emissions, converting the gas to a liquid form, and then sequestering (storing) it in the ocean or underground in a geologically stable rock formation.

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G. We all pay external costs.

H. Fossil fuel extraction has mixed consequences for local people.

1. Eminent domain is the policy by which courts set aside private property rights to make way for projects judged to be for the public good.

I. Dependence on foreign energy affects economic security.

1. This became clear in 1973, when the Organization of Petroleum Exporting Countries (OPEC) resolved to stop selling oil to the United States.

VI.

Energy Efficiency and Conservation 1. Energy efficiency describes the ability to obtain a given amount of output while using less energy input. Energy conservation describes the practice of reducing wasteful or unnecessary energy use.

A. Efficiency and conservation bring benefits.

1. The United States cut in half its energy intensity, or energy use per dollar of gross domestic product (GDP). Lower energy intensity indicates greater efficiency, and these data show that the United States now gets twice as much economic bang for its energy buck.

B. Personal actions and efficient technologies are two routes to conservation.

1. As individuals, we can make conscious choices to reduce our energy consumption.

2. As a society, we can conserve energy by developing technologies and strategies to make our energy-consuming devices and processes more efficient.

3. We can improve the efficiency of our power plants through cogeneration, in which excess heat produced during the generation of electricity is captured and used to heat nearby workplaces and homes and to produce other kinds of power.

4. In homes, offices, and public buildings, a significant amount of heat is needlessly lost in winter and gained in summer because of poor design and inadequate insulation. Improvements in design can reduce the energy required to heat and cool buildings.

5. Many consumer products, from lightbulbs to appliances, have been reengineered through the years to enhance efficiency.

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6. Automotive technology represents perhaps our best opportunity to conserve large amounts of fossil fuels fairly easily.

C. Automobile fuel efficiency is a key to conservation.

D. The rebound effect cuts into efficiency gains.

1. Energy efficiency is a vital pursuit, but it may not always save as much energy as we expect. This is because gains in efficiency from better technology may be partly offset if people engage in more energy-consuming behavior as a result.

E. We need both conservation and renewable energy.

Key Terms carbon capture and storage clean coal technologies coal cogeneration crude oil directional drilling electricity eminent domain energy conservation energy efficiency energy intensity EROI fossil fuels fracking hydraulic fracturing methane hydrate mountaintop removal mining

natural gas net energy oil oil sands oil shale Organization of Petroleum Exporting Countries (OPEC) peak oil petroleum proven recoverable reserve rebound effect refining reserves-to-production ratio (R/P ratio) shale oil tar sands

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Teaching Tips 1. Discuss the debate surrounding the Arctic National Wildlife Refuge issue by using the following resources: • Provide students with a visual reference by showing the video Arctic Quest: Our Search for Truth. This program, distributed by The Video Project (www.videoproject.com), follows a group of high school students as they travel to Alaska to talk to the people and see the habitat and wildlife of the ANWR for themselves. As your students are viewing the program, ask them to write down the pros and cons of oil exploration and drilling in the ANWR. • Search for policy updates on the issue at the US House of Representatives’ website (www.house.gov). Be aware that the results of a search are not listed chronologically.

• The views of the native people fall on both sides of the ANWR debate. Ask your students to search for information about the native people of the area— the Gwich’in Nation and Inupiat Eskimos. What are their views on the issue of oil exploration and drilling in the ANWR? How do they depend on the environment for their livelihoods? How do they think oil drilling would affect or improve their lives?

2. Discuss with your students how electricity is produced in your area, providing them with information about local power plants. Are they fueled by renewable or nonrenewable resources? Are there any documented environmental impacts, specific incidents, or political issues that have surrounded these power plants, their fuel sources, or their waste products? For instance, the Mohave Generating Station, south of Las Vegas, was cited repeatedly over the years for violating the Clean Air Act. Rather than spend the money to upgrade the plant, Southern California Edison closed it on Jan. 1, 2006. This closure also resulted in the closure of the Black Mesa coal mine on the Navajo reservation in Arizona, which supplied the plant with coal. Many people rejoiced that the environmental damage from both the station and the mine would stop, but workers at the mine complained of having no other source of nearby jobs and possibly having to leave the reservation, disrupting entire communities.

3. Have student groups (3–6 students per group) do presentations on power generation or make posters for display. Each group will be an “expert” on one power source (coal, nuclear, natural gas, solar, wind, hydropower, and so on).

The group should know basic information about the power source: how it is generated; how expensive it is to set up; how frequent and difficult is the maintenance; whether it saves or costs money in the current market; and what pollution, health hazards, or environmental hazards the manufacture of the equipment, the fuel, or the power generation will create. The rest of the class interacts with the experts by asking questions and debating which source is best 305 ..

for the environment.

4. Investigate the safety of mines in your state by visiting the US Department of Labor Mine Safety and Health Administration Web page (www.msha.gov/). If you have multiple mining sites nearby, you may want to have your students, either individually or in small groups, study each mine and prepare a short report on its history, ecology, and safety record.

Additional Resources Websites 1. Coalbed Methane Outreach Program (CMOP), US Environmental Protection Agency (EPA) (www.epa.gov/cmop) The EPA has provided a resource portal that examines the development and use of coalbed methane (CBM) and coal mine methane (CMM).

2. Fossil Fuels, Office of Fossil Energy, US Department of Energy (www.fossil.energy.gov/education) This student-oriented website is a primer on fossil fuel energy, with coverage of coal, oil, and natural gas.

3. What Coal Miners Do, United Mine Workers of America (www.umwa.org) The types of coal mines and mining processes are described at this website, along with images of coal miners at work.

4. OPEC, Organization of the Petroleum Exporting Countries (www.opec.org/opec_web/en) This web gateway provides access to publications and information produced by OPEC.

Audiovisual Materials 1. The Cost of Coal, NOW with Bill Moyers, 2002, PBS Home Video (www.pbs.org/now/science/coal.html) In this episode, Bill Moyers reports on the rescue of nine Pennsylvania miners, and goes on to discuss our reliance on coal and its environmental impact.

2. Arctic Quest: Our Search for Truth, 2000, produced by Jeff Barrie and Tyson Miller, and distributed by The Video Project (www.videoproject.com) This video follows five environmentally concerned high school students as they travel from a Youth Environmental Summit (YES) to find out for themselves about the issues surrounding oil drilling in the Alaskan national wilderness.

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3. Power Shift: Energy + Sustainability, 2003, produced by Kirk Bergstrom and distributed by The Video Project (www.videoproject.com) This four-part series explores how energy touches our daily lives and examines vital energy issues, suggesting ways that students can create a sustainable future. It is available in VHS and DVD formats.

4. The Curse of Oil, 2003, distributed by Films for the Humanities and Sciences (www.films.com) This program examines the promise of and problems caused by the discovery of oil in the developing countries of Ecuador and Angola. It is available in VHS and DVD formats.

5. Oil on Ice, 2005, Lightyear Studio production directed by Bo Boduart and Dale Djerassi (www.oilonice.org) Visually stunning tour through the Arctic National Wildlife Refuge with an introduction to its wildlife and people. Shows the politically controversial aspects of what is dubbed “America’s Last Wilderness” through discussions in the halls of Congress to interviews with First Nation people. It is available in DVD format.

Weighing the Issues Clean Coal and Carbon Capture Facts to consider: This answer will be at the discretion of each student. However, in the text it is clear that the drawbacks outweigh the potential benefits and that we cannot rely on this counteraction of burning fossil fuels alone. On the plus side, such facilities could enable us to keep on burning our cheapest and most abundant fossil fuel source in a way that does not contribute to climate change.

Energy experts are not ready to rely on carbon capture and storage quite yet, however. At this point, the technology is too unproven to be the central focus of a clean energy strategy. We do not know if we can ensure that carbon dioxide will stay underground once injected there, and we do not know whether these attempts might trigger earthquakes. Injection could, in some cases, contaminate groundwater supplies, and injecting carbon dioxide into the ocean would acidify its waters.

Finally, many renewable energy advocates fear the CCS approach takes the burden off emitters and prolongs our dependence on fossil fuels rather than facilitating a shift to renewables. This—in addition to all of the other side effects (referenced in the chapter) from extraction, purification, and utilization of fossil fuel usage— should sway the student towards renewable alternatives, even though this has yet to be covered in the text. However, the students’ personal experience with the subject matter will guide their answers.

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Drill, Baby, Drill?

Facts to consider: Student answers will vary according to their knowledge, background, priorities, and experience. Students may base their answers on past case studies, such as the impact of catastrophic events—such as the Gulf oil spill, or recent earthquakes triggered by hydraulic fracturing—and more widespread impacts of exploring for and extracting fossil fuels in the developing world.

Important to note would be how much recoverable fuel would be available in the exploited areas. Also important would be how soon the public would be able to access this fuel source and for how long. Students can access previous chapters for information about forming and enforcing environmental policy.

More Miles, Less Gas Facts to consider: The first questions require an individual response. If all US vehicles increased fuel efficiency by 10 mpg, Americans would conserve about 1.72 billion barrels of oil annually, assuming US total annual oil consumption of 7.7 billion barrels, of which 67% is used for transportation. This calculation does not take into account that the transportation portion of oil use presumably includes planes and railroads. It also does not account for the fact that 20.8 mpg is the average fuel efficiency for new vehicles, not all vehicles, and not commercial vehicles such as large trucks.

Other ways to conserve fossil fuels include improving the efficiency of fossil-fuelpowered plants, further developing renewable resource technologies for transportation and energy production, improving the energy efficiency of household and industrial appliances, and designing buildings in ways that use renewable forms of energy. While these conservation methods would help, probably none of them would have as much of an effect as would improving fossil fuel efficiency in vehicles.

The Science behind the Story How Do We Find and Estimate Fossil Fuel Deposits?

Observation: Drilling for oil or gas is a risky business.

Question: How much oil does Alaska’s North Slope hold?

Hypothesis: A substantial amount of recoverable oil is held on Alaska’s North Slope.

Experiment: Scientists collect data from seismometers at multiple surface locations and run the data through computer programs. By analyzing how long it takes all the waves to reach the various receiving stations, and how strong they are 308 ..

at each site, researchers can triangulate and infer the densities, thicknesses, and locations of underlying geologic layers. Using data from such techniques, geologists with the US Geological Survey (USGS) in 1998 assessed the subsurface geology of the Arctic National Wildlife Refuge on Alaska’s North Slope. Over three years, dozens of scientists conducted fieldwork and combined their results with a reanalysis of 2300 km (1400 mi) of seismic survey data that industry had collected in the 1980s.

Results: After studying their resulting subsurface maps, USGS scientists concluded, with 95% certainty, that between 11.6 and 31.5 billion barrels of oil lay underneath the region of the refuge that Congress has debated opening for drilling.

Implications: In its estimate for the Arctic Refuge, the USGS calculated that technically recoverable oil totaled 4.3–11.8 billion barrels, with a mean estimate of 7.7 billion barrels (just more than 1 year of US consumption).

What Were the Impacts of the Gulf Oil Spill Observation: During the Gulf oil spill, oil was leaking at a rate of up to 64,000 barrels a day.

Question: What has scientific research told us about the actual impacts of the Gulf oil spill?

Experiment: Using underwater imaging, aerial surveys, and shipboard water samples, researchers tracked the movement of oil up through the water column and across the Gulf. A team of researchers led by Charles Fisher of Penn State University embarked on a regular survey of deepwater coral across the Gulf of Mexico in late 2010 and continues monitoring these coral communities.

Outcome: The ecological damage caused by the spill had measurable consequences for people. The region’s mighty fisheries were shut down, forcing thousands of fishermen out of work. The government tested fish and shellfish for contamination and reopened fishing once the fish were found to be safe, but consumers still balked at buying Gulf seafood. Beach tourism remained low all summer because visitors avoided the region. Together, losses in fishing and tourism totaled billions of dollars.

Researchers found that oil did not penetrate to the roots of most plants and that oiled grasses were sending up new growth.

The impacts of the oil on birds, sea turtles, and marine mammals were less difficult to assess. Officially confirmed deaths numbered 6,104 birds, 605 turtles, and 97 mammals.

Finally, the ecological impacts of the spill had measurable impacts on people.

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Local Connections What are students, faculty, or administrators on your campus doing to encourage energy efficiency? What is being done on your campus to conserve energy or to reduce fossil fuel use? Is there a call for your college or university to divest its investment holdings from fossil fuel corporations? What is being done to encourage the use of renewable energy? What additional steps, if any, regarding fossil fuel use and policies do you think your institution should take, and why?

Class time: one class period or could be completed as a homework assignment.

For some schools, this information may be available on a campus sustainability website. For other schools, students may need to contact administrators or other campus officials to learn more about campus energy use. Students may need to learn more about alternative energies before completing the final questions in the prompt. Chapters 20 and 21 cover conventional energy alternatives and new renewable energy sources, respectively.

Calculating Ecological Footprints Hectares of land for fuel production You

1,649

Your class

Answers will vary

Your state

Answers will vary

United States

5.4  1011

1. This method yields an answer almost 290 times as large as that from the Wackernagel and Rees method. It illustrates the potential footprint if we tried to satisfy our energy use from present-day NPP, not fossil NPP accumulated over the past hundreds of millions of years. The fossilization process stores only a small fraction of 1% of the NPP. 2. The hectares of land for fuel production that the United States would require to meet its energy use from the present-day NPP is an amount that is multiple times the land area of Earth.

3. (1.5  1010 hectares) ÷ (1,649 hectares/person) = 9,096,422 people. This is only about 0.11% of the current world population. This pointedly illustrates how dependent the US standard of living is on energy consumption—far in excess of what could be grown renewably. It is not realistic to think that Earth’s population will shrink to 0.11% of what it is today, but neither is it realistic to think that Earth can support billions of people, each consuming energy like the average American.

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20 Conventional Energy Alternatives Chapter Objectives This chapter will help students: Discuss reasons for seeking alternatives to fossil fuels Summarize the contributions to world energy supplies of conventional alternatives to fossil fuels Describe nuclear energy and explain how we harness it for electrical power Assess the benefits and drawbacks of nuclear power, and discuss the societal debate over this energy source Describe established and emerging sources of, and techniques involved in, harnessing bioenergy, and assess bioenergy’s benefits and shortcomings Outline the scale, methods, and impacts of hydroelectric power

Lecture Outline I.

Central Case Study: Will Sweden Free Itself of Fossil Fuels?

A. In 1980, Sweden voted to phase out its nuclear power program, shutting down all nuclear plants by the year 2010.

B. As 2010 arrived, Sweden found itself relying on 10 nuclear reactors for more than 30% of its energy supply and more than 40% of its electricity.

C. Sweden does not favor expanding fossil fuel use, so to fill the gap the government has promoted the research and development of renewable energy sources.

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D. Sweden soon made itself an international leader in renewable energy alternatives and today gets nearly half its energy from renewable sources.

E. The Swedish government’s shifting policies have reflected changing public sentiments.

F. In 2015, Sweden’s new prime minister, Stefan Löfven, announced that his government would aim one day to make Sweden completely free of fossil fuels.

II.

Alternatives to Fossil Fuels A. Nuclear power, bioenergy, and hydropower are conventional alternatives.

B. Conventional alternatives provide much of our electricity.

1. Fuelwood and other bioenergy sources provide 10% of the world’s energy, nuclear power provides about 5%, and hydropower provides about 2%. The less-established “new renewable” energy sources together account for just over 1%.

III.

Nuclear Power 1. First developed commercially in the 1950s, nuclear power (the use of nuclear energy to generate electricity) experienced most of its growth during the 1970s and 1980s.

A. Fission releases nuclear energy in reactors to generate electricity.

1. Nuclear energy is the energy that holds together protons and neutrons in the nucleus of an atom. We harness this energy by converting it to thermal energy inside nuclear reactors, facilities contained within nuclear power plants.

2. The reaction that drives the release of nuclear energy inside nuclear reactors is nuclear fission, the splitting apart of atomic nuclei.

3. If not controlled, this chain reaction becomes a runaway process of positive feedback—the process that creates the explosive power of a nuclear bomb.

B. Nuclear energy comes from processed and enriched uranium.

1. Uranium is used for nuclear power because it is radioactive.

Radioactive isotopes, or radioisotopes, emit subatomic particles and high-energy radiation as they decay into lighter radioisotopes, until they become stable isotopes. Each radioisotope decays at a rate determined by that isotope’s half-life, the time it takes for half the atoms to give off radiation and decay.

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2. We obtain uranium from various minerals in naturally occurring ore.

Uranium-containing minerals are uncommon, and uranium ore is in finite supply, so nuclear power is generally considered a nonrenewable energy source.

3. More than 99% of the uranium in nature occurs as the isotope uranium-238. Uranium-235 (with three fewer neutrons) makes up less than 1% of the total. Because 238U does not emit enough neutrons to maintain a chain reaction when fissioned, we use 235U for commercial nuclear power. Therefore, we must process the ore we mine to enrich the concentration of 235U to at least 3%.

4. After several years in a reactor, the decayed uranium fuel no longer generates adequate energy, so it must be replaced with new fuel. In some countries, the spent fuel is reprocessed to recover the remaining energy. However, this process is costly relative to the market price of uranium, so most spent fuel is disposed of as radioactive waste.

C. Nuclear power delivers energy more cleanly than fossil fuels.

1. Fission enables nuclear power plants to generate electricity without creating air pollution from stack emissions.

2. Nuclear power has additional advantages over fossil fuels—coal in particular. For residents living downwind from power plants, scientists calculate that nuclear power poses far fewer chronic health risks from pollution.

3. Nuclear power also has drawbacks. a. One is that the waste it produces is radioactive, and arranging for safe disposal of this waste has proved challenging. b. The second main drawback is that if an accident occurs at a power plant, or if a plant is sabotaged, the consequences can potentially be catastrophic.

D. Fusion remains a dream.

1. Nuclear fusion—the process that drives our sun’s vast output of energy, and the force behind hydrogen bombs (thermonuclear bombs)—involves forcing together the small nuclei of lightweight elements under extremely high temperature and pressure. The hydrogen isotopes deuterium and tritium can be fused together to create helium, releasing a neutron and a tremendous amount of energy.

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2. Overcoming the mutually repulsive forces of protons in a controlled manner is difficult, and fusion requires temperatures of many millions of degrees Celsius. Despite billions of dollars in funding and decades of research, fusion experiments in the lab still require scientists to input more energy than they produce from the process.

3. If we could find a way to control fusion in a reactor, the potential payoffs would be immense. We could produce vast amounts of energy using water as a fuel, and the process would create only low-level radioactive wastes, without pollutant emissions or the risk of dangerous accidents, sabotage, or weapons proliferation.

E. Nuclear power poses small risks of large accidents.

1. Three events have been most influential in shaping public opinion about nuclear power. a. In Pennsylvania in 1979, a combination of mechanical failure and human error at the Three Mile Island plant caused coolant water to begin draining from the reactor vessel, temperatures to rise inside the reactor core, and metal surrounding the uranium fuel rods to start melting, releasing radiation. This process is termed a meltdown, and at Three Mile Island it proceeded through half of one reactor core. b. In 1986, an explosion at the Chernobyl power plant in Ukraine was the most severe nuclear power plant accident the world has yet seen. Human error, combined with unsafe reactor design, resulted in explosions that destroyed the reactor and sent clouds of radioactive debris billowing into the atmosphere. c. A 9.0 magnitude earthquake in 2011 affected the operation of several of Japan’s nuclear plants, most notably Fukushima Daiichi. Here, the earthquake shut down power and the tsunami flooded the plant’s emergency power generators.

F. We are managing risks from nuclear power and nuclear weapons with some success.

G. Waste disposal remains a challenge.

1. Even if nuclear power generation could be made completely safe, and even if we could recycle all weapons-grade fuel into fuel for power plants, we still would be left with the conundrum of what to do with spent fuel rods and other radioactive waste. This waste will continue emitting radiation for as long as our civilization exists.

2. Currently, nuclear waste from power generation is being held in temporary storage at nuclear power plants around the world.

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3. Because storing waste at many dispersed sites creates a large number of potential hazards, nuclear waste managers would prefer to send all waste to a single, central repository that can be heavily guarded.

H. Nuclear power’s growth has slowed.

1. Almost every nuclear plant has turned out to be more expensive than expected. Plants have also aged more quickly than expected because of problems that were underestimated. Finally, shutting down a plant can be more expensive than the original construction.

2. These issues make nuclear-power-generated electricity more expensive than electricity from other sources. Governments are still subsidizing nuclear power to keep electricity costs to ratepayers down.

3. Nonetheless, nuclear power remains one of the few currently viable alternatives to fossil fuels with which we can generate large amounts of electricity in short order.

4. With future growth for nuclear power uncertain, and with climate change worsening, our society must determine where we will turn for clean and sustainable energy. Increasingly, people are looking to renewable sources of energy: energy sources that are replenished naturally and cannot be depleted by our use.

I.

A new generation of reactors could transform and revitalize nuclear power.

1. Small modular reactors are built at factories and could be used individually or in combination at power plants.

2. Generation IV reactors use a diversity of novel fuels, coolants, and approaches that boost efficiency, reduce radioactive waste, enhance safety, and reduce cost.

IV.

Bioenergy 1. Bioenergy—also known as biomass energy—is energy obtained from biomass. Biomass consists of organic material derived from living or recently living organisms, and it contains chemical energy that originated with sunlight and photosynthesis.

A. We gain bioenergy from many sources.

1. Although fossil fuels and electricity are replacing traditional energy sources as developing nations industrialize, fuelwood, charcoal, and manure still account for one-third of energy use in these nations—and up to 90% in the poorest nations.

2. Biomass is renewable only if it is not overharvested.

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3. Some of these biomass sources can be burned in power plants to produce biopower, generating heat and electricity. Other sources can be converted into biofuels, liquid fuels used primarily to power automobiles.

B. We use biomass to generate electricity.

1. Some waste products can be used as sources for biopower.

2. We are beginning to grow certain types of plants as crops to generate biopower.

3. Power plants built to combust biomass operate like those fired by fossil fuels: combustion heats water, creating steam to turn turbines and generators, thereby generating electricity.

4. At small scales, farmers, ranchers, or villages can operate modular biopower systems that use livestock manure to generate electricity. At large scales, the forest products industry is using its waste to generate power and industrialized farmers are growing bioenergy crops.

5. Biomass power has both benefits and drawbacks.

C. Ethanol can power automobiles.

1. Ethanol is the alcohol in beer, wine, and liquor. It is produced by fermenting biomass.

2. Any vehicle with a gasoline engine runs well on gasoline blended with up to 10% ethanol, but automakers are also producing flexible-fuel vehicles that run on E-85, a mix of 85% ethanol and 15% gasoline.

D. Ethanol is not our most sustainable energy choice.

1. One reason is that growing corn to produce ethanol intensifies pesticide use, fertilizer use, fresh water depletion, and other impacts of industrialized agriculture. Corn ethanol crops take up millions of acres of land that might otherwise be left in a natural condition or developed for other purposes.

2. Even at our current level of production, ethanol already competes with food production and drives up food prices.

3. Growing corn for ethanol also requires substantial inputs of fossil fuel energy.

4. Moreover, corn ethanol yields only a modest amount of energy relative to the energy that needs to be input.

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E. Biodiesel powers diesel engines.

1. Biodiesel is a fuel produced from vegetable oil, used cooking grease, or animal fat. Traditional diesel engines can run on 100% biodiesel.

2. Replacing diesel with biodiesel cuts down on emissions.

3. Using waste oil as a biofuel is sustainable, but most biodiesel today, like most ethanol, comes from crops grown specifically for the purpose.

F. Novel biofuels are being developed.

1. One promising next-generation biofuel crop is algae.

2. Relying on any monocultural crop for energy may not be sustainable.

With this in mind, researchers are refining techniques to produce cellulosic ethanol by using enzymes to produce ethanol from cellulose, the substance that gives structure to all plant material.

G. Is bioenergy carbon-neutral?

1. In principle, energy from biomass is carbon-neutral, releasing no net carbon into the atmosphere. However, in practice things are not so simple.

2. International climate change policy so far has failed to encourage sustainable bioenergy approaches.

V.

Hydroelectric Power 1. In hydroelectric power, or hydropower, the kinetic energy of flowing river water is used to turn turbines and generate electricity.

A. Modern hydropower uses three approaches.

1. Most of our hydroelectric power today comes from impounding water in reservoirs behind concrete dams that block the flow of river water and then letting that water pass through the dam. Because water is stored behind dams, this is called the storage technique.

2. An alternative approach is the run-of-river technique, which generates electricity without greatly disrupting a river’s flow.

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3. To better control the timing of flow, pumped-storage hydropower can be used. In pumped storage, water is pumped from a lower reservoir to a higher reservoir during times when demand for power is weak and prices are low. When demand is strong and prices are high, water is allowed to flow downhill through a turbine, generating electricity.

B. Hydroelectric power is renewable yet has impacts.

1. Hydropower has three clear advantages over fossil fuels. First, it is renewable: as long as precipitation falls from the sky and fills rivers and reservoirs, we can use water to turn turbines.

2. Second, hydropower is efficient.

3. Third, no carbon compounds are burned in the production of hydropower, so no carbon dioxide (CO2) or other pollutants are emitted into the atmosphere, and this helps safeguard air quality, climate, and human health.

4. Although it is renewable, efficient, and produces little air pollution, hydropower does exert negative impacts. Damming rivers destroys habitat for wildlife as riparian areas above dam sites are submerged and those below dam sites often are starved of water. Because water discharge is regulated to optimize electricity generation, the natural flooding cycles of rivers are disrupted. Sediments become trapped behind dams, where they begin filling the reservoir.

5. Dams also cause thermal pollution because water downstream may become unusually warm if water levels are kept unnaturally shallow, then periodic flushes of cold water may occur from the release of reservoir water. Dams generally block the passage of fish and other aquatic creatures, effectively fragmenting the river and reducing biodiversity in each stretch.

C. Hydroelectric power is widely used, but it may not expand much more.

1. Hydropower accounts for one-sixth of the world’s electricity production.

2. Most of the world’s rivers that offer excellent opportunities for hydropower are already dammed.

3. Overall, hydroelectric power will likely continue to increase in developing nations that have yet to dam their rivers, but in developed nations hydropower growth will likely slow down.

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Key Terms biodiesel bioenergy biofuels biomass biomass energy biopower cellulosic ethanol Chernobyl ethanol Fukushima Daiichi hydroelectric power

hydropower meltdown nuclear energy nuclear fission nuclear fusion nuclear power nuclear reactors pumped storage run of river storage Three Mile Island

Teaching Tips 1. Dams provide many benefits but cause many problems. Have students research both sides of the issue and write position papers or, in groups, present the point of view of a particular group of stakeholders. Their papers can be focused on a local dam or a proposed dam, or can address the issue in general. Some good websites to get students started are: • National Hydropower Association (www.hydro.org). According to its website, “The National Hydropower Association is the only national trade association dedicated exclusively to representing the interests of the hydropower industry.

Its members span the breadth of the industry and all related fields.”

• The US Society on Dams (www.ussdams.org). This organization claims to be “the nation’s leading organization of professionals dedicated to advancing the role of dams for the benefit of society.”

• World Commission on Dams (WCD) (www.internationalrivers.org/ campaigns/the-world-commission-on-dams). The WCD released its report on Dams and Development (November 2000) and established a website containing the full report as well as the global studies and reviews that went into it.

2. Ask students to visit www.fueleconomy.gov to find the gas mileage, greenhouse gas emissions, and air pollution ratings for their car (or a family member’s car).

This government website also has information about gas mileage, hybrid electric vehicles, and hydrogen fuel cell vehicles. Ask your students how their cars compare to hybrid electric cars, or those that run on E85, and what kind of vehicle produces the most greenhouse gas emissions.

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3. The US Department of Energy’s Office of Nuclear Energy (energy.gov/ne/officenuclear-energy) has a variety of articles and programs. Divide your students into small groups and have them choose one of the “Program Overviews” to read and present to the class. Topics include Advanced Fuel Cycle Initiative, Isotope Programs, Nuclear Hydrogen Initiative, Proliferation Resistance, Space Radioisotope Power Systems, and many others.

4. Biomass energy has become a subject of much interest in the United States in recent years. The Biomass Energy Research Association, BERA (www.biomasscenter.org/), has some basic information from an industry viewpoint. It is an association of biofuel researchers, companies, and advocates that promotes education and research on renewable biomass energy and waste-toenergy systems.

5. An important issue in preparing your course material is to have some idea of your students’ backgrounds. Research into knowledge acquisition has shown that students’ prior knowledge and/or misconceptions have a great deal to do with their ability to take in, understand, and retain new information about a topic.

Course content that is too far removed from a student’s current knowledge base will be inaccessible. There is, however, a zone of proximal development (ZPD).

This is a zone of material proximal to, but just beyond, the student’s current level of knowledge, where information is new but accessible based on what they already know.

In science, we often forget that our discipline is heavily laden with terminology.

Even the simplest topic, when presented in a lecture filled with acronyms and terms, can overwhelm a nonscience major.

Start a new topic with a brief assessment of current student knowledge. Have small groups of students list facts and terms they think they know already, and then ask volunteers to enumerate some of the terms and concepts. If no one in the class knows the difference between the functions of the EPA and the CDC, for example, you may need to alter your first lessons accordingly. After doing this for a few semesters, you will have a good feel for the average level of knowledge your students have relating to each topic in the course and can be assured that you are starting your topic coverage within the ZPD for most of them.

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Additional Resources Websites 1. USNRC Home Page, US Nuclear Regulatory Commission (NRC) (www.nrc.gov) The NRC home page provides links to basic information on its website regarding nuclear energy facilities, fuel, and waste disposal. You can find information about waste facilities, including the proposed high-level waste repository at Yucca Mountain.

2. Frontline: Why Do Americans Fear Nuclear Power?, WGBH, PBS (www.pbs.org/wgbh/pages/frontline/shows/reaction) This web resource is a companion to an episode of the PBS series Frontline. The episode examines the attitudes of the general public toward nuclear energy.

3. Hydroelectric Energy, Environmental Literacy Council (www.enviroliteracy.org/energy/renewable-energy/hydroelectric-power) This web resource contains general information about how hydroelectric power is generated as well as many useful links to governmental, university, and public organization websites concerning hydroelectric power.

4. Public Transportation.org, provided by the American Public Transportation Association (www.publictransportation.org).

View public transportation options by state.

Audiovisual Materials 1. Chernobyl Heart: The Dark Side of Nuclear Power, 2003, distributed by Films for the Humanities & Sciences (www.films.com) This Academy Award–winning program reexamines what happened at the Ukrainian reactor and investigates subjects of public concern, such as the storage of radioactive material and the overall safety of the nuclear industry.

2. American Experience: The Hoover Dam, 2006, PBS Home Video (www.pbs.org/wgbh/americanexperience/films/hoover/) This PBS program shows the history of the Hoover Dam and its role in transforming the West by providing water and electricity.

3. Energy and Resources, 2006, produced by Cambridge Educational Productions and distributed by Films for the Humanities & Sciences (cambridge.films.com) This video explores the development of alternative energy resources that may someday completely replace fossil fuels as primary energy sources.

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Weighing the Issues Choose Your Risk Facts to consider: Answers will vary. One approach to answering this question would be to consider the possible long-term consequences that leaks of radioactive material from a reactor may have on the student, especially in terms of the longevity of risk. There may be some discussion about the partial meltdown at Three Mile Island and the tragedy at Chernobyl, and how toxic fallout may affect human health for generations. An alternative approach to responding to the question would be to look at the more short-term health effects, such as the myriad respiratory ailments that affect citizens living near coal-burning plants. These health problems can also have long-term effects.

How to Store Waste?

Facts to consider: There are pros and cons to storing nuclear waste at a central location or at dispersed sites. Transport of existing waste to a central location increases the chance of an accident and makes the shipment vulnerable to terrorist attack. Waste transport would be costly, with highways and roads blocked for security and safety reasons, placing a temporary strain on the transit systems of various localities. Having a single nuclear waste storage facility may make it easier for terrorists to attack and remove some of the waste for various nefarious purposes.

However, there is a logical counter to every con discussed so far. Placing the waste at a single location may make it easier to defend against terrorist attacks by concentrating the protective assets in that location. Transport of chemical hazardous waste has been accomplished for many years, so the transport of radioactive waste should not be a problem. Finally, having many dispersed sites decreases the chances of a terrorist attack or an accident that may release large amounts of radioactive material. Students will have a variety of responses.

More Nuclear Power?

Facts to consider: This question requires a personal response. Proponents of nuclear power may posit that the technology is already being used and that electricity generated by nuclear energy is more efficient and cleaner than burning coal, with a smaller ecological footprint than hydroelectrically-generated power. Opponents of nuclear power may counter with its drawbacks, including the cost of construction, maintenance, and decommissioning; the effort and expense of developing emergency plans and gathering equipment and supplies in the event of a nuclear disaster; and problems with waste transport, storage, and monitoring. Students who are opposed to nuclear energy may also point out that nuclear power plants are heavily subsidized by the government, and perhaps federal funds may be better spent on the research and development of alternative energy sources to fossil fuels.

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Biofuels Facts to consider: Student responses will vary, depending on how up to date they are on the issue or how willing they are to examine the issue in closer detail. This topic is a current issue in the alternative fuels debate. The scientific proponents are headed by a group of researchers at the University of California at Berkeley, whose findings were published in the Jan. 27, 2006, edition of Science (Vol. 311:5760, 506–508).

Alexander Farrell and his associates posit that a metaanalysis of past studies shows that obsolete and irrelevant data were used. When these errors are corrected, the calculations show that there is more energy in ethanol fuel than was expended to produce that fuel.

Opponents of using ethanol as an alternative fuel include David Pimentel of Cornell University and Tad Patzek of the University of California-Berkeley, whose study was published in Natural Resources Research (Vol. 14:1, 65–76) in 2005. These researchers argue that one must take into account the fuels necessary to construct and transport farm equipment to a farm, to fertilize fields, to apply pesticides to growing plants, to harvest the crop, etc., in order to get a true cost for producing ethanol as fuel. Students will need to review the data and make their own judgments.

Additional considerations to be discussed are ecological, social, and economic, as seen in Brazil, which grows sugarcane for fuels. On the ecological side, deforestation and degradation of soils would increase as farming plants for fuel becomes a lucrative business. Loss of forest would decrease biodiversity. The sugarcane is burned just prior to harvest to remove leaves and snakes from the fields. While previously the smoke from these fires would concentrate in cities, rural areas are now becoming heavily laden with air pollutants.

From a social perspective, Brazil is having problems with poor itinerant farm workers in rural areas who make low wages and have work only during the sugarcane harvest season—1–2 months a year. On the economic side, as fuel crops become more lucrative than food crops, there is the possibility that farmers will grow more crops for fuel and less for food, causing food shortages and inflated food prices. In addition, the question of continued government subsidies becomes important—how long will the government continue to subsidize corn and sugarcane farms for fuel crops? And, if the government subsidizes farms for fuel crops, with most of the farmland being owned by mega-agribusiness, who makes the profit?

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The Science behind the Story What Health Impacts Have Resulted from Chernobyl and Fukushima?

Question: What are the long-term health impacts that may have been caused by the Chernobyl incident and meltdowns at Japan’s Fukushima Daiichi nuclear power plant in 2011?

Study: In an effort to reach consensus, the World Health Organization (WHO) engaged 100 experts to review all studies through 2006 and issue a report summarizing what scientists had learned in the 20 years since the accident. In 2008, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) issued a comprehensive report as well.

In 2012, John Ten Hoeve and Mark Jacobson of Stanford University used a global atmospheric model together with data on radiation, population dispersion, and weather in the days following the Japanese event to estimate radiation levels people received.

Results: While the social and psychological effects on evacuated residents were substantial, there was very little evidence of any long-term physical health effects from the Chernobyl disaster. The exception to this finding was that thyroid cancer significantly increased in children, possibly because the thyroid, which concentrates iodine in the human body, is more active in children and because radioactive iodine was the most common radioactive isotope released into the air early in the disaster.

Rates of thyroid cancer also increased in adults.

In the journal Energy and Environmental Science, scientists predicted that Fukushima’s radiation would eventually produce 125 cancer-related deaths and 178 cases of nonfatal cancer. Large uncertainties attended both estimates; the projected number of total cases ranged from 39 to 2900.

Which Energy Sources Have the Best EROI Values?

Question: How do we make valid comparisons among the amounts of emissions released by all energy sources? What about the energy return on investment (EROI)?

Study: To fully and accurately measure the denominator in an EROI ratio, the researcher must conduct a thorough life-cycle analysis, summing up all the energy invested at each stage in the life cycle of the process. Charles Hall of SUNY College of Environmental Science and Forestry in Syracuse, New York, has been one of the pioneers in calculating EROI values. In 2014, he and students Jessica Lambert and Stephen Balogh surveyed recent research and compiled EROI estimates for major energy sources.

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Results: Hydroelectric power had the best EROI value, averaging 84. This means that for each unit of energy we invest in hydropower, we produce 84 units of energy.

At the other end of the spectrum were biodiesel, oil sands, and ethanol, with EROIs of only 2:1, 4:1, and 5:1, respectively.

Implications: The 2014 review by Hall and his students made clear that EROI values for fossil fuels were historically very high but have been dropping through the years.

This is because we have already extracted the easy deposits and now need to expend more and more energy to reach the less-accessible deposits that remain. Newer, unconventional fossil fuel resources such as oil sands and shale oil have low EROI values. This means that if we switch to these sources as conventional oil begins to run out, we will deplete them rapidly (while producing a great deal of pollution), because a great deal of energy will need to be devoted to extracting and processing them.

Local Connections Do some research to find out where your campus gets its energy. What percentage of total energy on your campus comes from fossil fuels? From nuclear power? From bioenergy? From hydropower? From other renewable sources such as wind or solar power? What about electricity: What percentages of electricity come from each of these sources? Are students on your campus making any attempts to urge a shift away from fossil fuels and toward alternative energy sources? If so, what is being done? What more do you think could be done or should be done?

Class time: one class period or could be completed as a homework assignment.

For some schools, this information may be available on a campus sustainability website. For other schools, students may need to contact administrators or other campus officials to learn more about campus energy use. For the second part of the question about advocacy, students may need to research beyond the school website.

Some schools have moved completely away from fossil fuels and their actions have been well-documented in the traditional press.

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Calculating Ecological Footprints Energy source

EROI

Coal (electricity)

12

Natural gas (electricity)

8

Nuclear power

14

Hydropower

84

Photovoltaic solar

10

Wind power

20

Ethanol

6

Biodiesel

2

1. Approximately 84. For nuclear, you would need to input approximately 6× that amount. For coal, you would need to input 7× that amount.

2. It is more efficient to obtain energy from wind than natural gas. Natural gas would have a larger footprint.

3. You would need to input 50 units. EROI = Energy returned / Energy invested.

Solve for energy invested: energy invested = energy returned/ EROI. Plug in numbers: energy invested = 100/2 = 50.

4. Answers will vary, but students should recognize that hydropower and wind have the highest EROIs while corn-based ethanol and biodiesel have the lowest EROIs.

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21 New Renewable Energy Alternatives Chapter Objectives This chapter will help students: Identify the major sources of renewable energy and assess their recent growth and future potential Describe solar energy and how we harness it, and evaluate its advantages and disadvantages Describe wind power and how we harness it, and evaluate its advantages and disadvantages Describe geothermal energy and how we harness it, and evaluate its advantages and disadvantages List ocean energy sources and describe their potential Survey approaches for energy storage, and discuss the potential role of hydrogen and fuel cells

Lecture Outline I.

Central Case Study: Harnessing Wind and Sun in Texas and Germany A. Texas and Germany have become global leaders in the transition from fossil fuels to new renewables.

1. Texas has encouraged wind power development by reducing

regulatory barriers to companies.

2. Germany has encouraged solar power development by enacting policies to incentivize companies to build solar.

B. In Texas, wind blows strongly across large regions of the western half of the state, while most of the population lives in the eastern half of the state.

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C. In 1999, the Texas state legislature passed a law that mandated utility companies to produce a quota of renewable energy.

1. In 2005, the quota was increased.

D. Minimal state regulation and tax credits at the federal level allowed thousands of wind turbines to be erected on land owned and leased from ranchers and farmers.

E. The western areas where wind is highest are far from the eastern areas, where most of the population resides. The government responded by expanding the transmission grid so that wind energy harnessed in the west could be transported to the east for use.

1. Under Texas Senate Bill 20 passed in 2005, the statewide grid manager, the Electric Reliability Council of Texas (ERCOT), and the Public Utility Commission of Texas designated “Competitive Renewable Energy Zones” in five western regions with the most power potential. Officials encouraged companies to develop wind farms in these regions, and then let them compete to sell power to ERCOT at the lowest prices.

F. By 2018, wind power had come to provide nearly 19% of Texas’ electricity.

G. Texans have some of the country’s cheapest electricity rates, thanks to wind power.

H. Germany now obtains more than 7% of its electricity from solar power— one of the highest rates in the world.

I. Germany has a feed-in tariff system whereby utilities are required to buy power from anyone who can generate power from renewable energy sources and feed it into the electrical grid. In response, German homeowners and businesses have rushed to install PV panels and are selling their excess solar power to utilities at a profit.

J. The feed-in tariffs apply to all forms of renewable energy.

K. Germany’s push for renewable energy dates back to 1990.

L. By 2050, Germany aims to obtain 80% of its electricity from renewable sources.

M. As Germany replaces fossil fuels with renewable energy, it is improving its air quality and helping to fight climate change.

N. The planned transition from fossil fuels in Germany has not been completely smooth, however. Following the Fukushima nuclear disaster in Japan in 2011, the German government shut down seven of its 15 nuclear power plants and promised to phase out the rest by 2022.

O. Germany’s experience is serving as an international model.

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II.

Shifting to Renewable Energy A. New renewable sources are growing fast.

1. As with other energy sources, the new renewables provide energy for three types of applications: (1) generating electricity, (2) heating air or water, and (3) fueling vehicles. Their potential is enormous, yet so far their contributions to our society’s overall energy budget remain small. Today, we obtain just under 2% of our global energy from the new renewable energy sources, whereas fossil fuels still provide 81% of the world’s energy.

2. The new renewable sources are making similarly small contributions to our global generation of electricity thus far.

3. Nations and regions vary in the renewable sources they use.

4. Although they currently make up a small proportion of our energy budget, the new renewable energy sources are growing quickly.

B. The new renewables offer advantages.

1. Use of new renewables has been expanding because of growing concerns over diminishing supplies of conventional fossil fuels and because of the many environmental and health impacts of fossil fuel combustion.

2. Shifting to renewable energy also creates new employment opportunities. The design, installation, maintenance, and management required to develop technologies and rebuild and operate our society’s energy infrastructure are becoming major sources of employment today, through green-collar jobs.

3. Whether we can—or even should—give up fossil fuels entirely and switch to 100% renewable energy remains a matter of some debate among energy experts.

C. Policy and investment can accelerate our transition from fossil fuels.

1. Rapid growth in renewable energy seems likely to continue as global population and consumption rise, easily accessible fossil fuel supplies decline, and people demand cleaner environments.

2. However, renewables can overcome technological and economic barriers if they are lent political support.

3. When a government boosts an industry with such policies, the private sector often responds with investment of its own, as private investors recognize an enhanced chance of success and profit.

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4. Yet the economics of renewable energy have been erratic.

5. There has never been a level playing field, nor a truly free market.

III.

Solar Energy 1. Each day, Earth receives enough solar energy, or energy from the sun, to power human consumption for a quarter of a century. On average, each square meter of Earth’s surface receives about 1 kilowatt of solar energy—17 times the energy of a lightbulb.

A. We can collect solar energy using passive or active methods.

1. In passive solar energy collection, buildings are designed to maximize the absorption of sunlight in winter yet keep the interior cool in the heat of summer.

2. Active solar energy collection makes use of devices to focus, move, or store solar energy.

B. Concentrating sunlight focuses energy.

1. We can intensify solar energy by gathering sunlight from a wide area and focusing it on a single point.

2. Concentrated solar power (CSP) is being harnessed by several methods. The dominant technology used so far is the parabolic trough approach, in which curved mirrors focus sunlight onto synthetic oil in pipes. The superheated oil is piped to an adjacent facility where it heats water, creating steam that drives turbines that in turn generate electricity.

3. CSP facilities need to be located in sunny areas, but they have great potential.

C. Photovoltaic cells generate electricity.

1. The most direct way to produce electricity from sunlight involves photovoltaic (PV) systems. Photovoltaic cells convert sunlight to electrical energy when light strikes one of a pair of plates made primarily of silicon, a semiconductor that conducts electricity. The light causes one plate to release electrons, which are attracted by electrostatic forces to the opposing plate. Connecting the two plates with wires enables the electrons to flow back to the original plate, creating an electrical current (direct current [DC]), which can be converted into alternating current (AC) and used for residential and commercial electrical power.

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2. Researchers are experimenting with variations on PV technology including thin-film solar cells, photovoltaic materials compressed into ultrathin sheets.

3. Photovoltaic cells of all types can be connected to batteries that store the accumulated charge until needed. Alternatively, producers of PV electricity can sell their power to their local utility if they are connected to the regional electric grid. a. In places where PV systems are connected to a power grid, homeowners can sell power to their utility in a process called net metering, in which the value of the power the consumer provides is subtracted from the consumer’s monthly utility bill.

D. Solar energy offers many benefits.

1. The fact that the sun will continue burning for another 4–5 billion years makes it inexhaustible as an energy source for human civilization.

2. Solar systems also allow for local, decentralized control over power.

3. Developing, manufacturing, and deploying solar technology also create new green-collar jobs.

4. A major advantage of solar power over fossil fuels is that it does not emit greenhouse gases and other air pollutants.

E. Location, timing, and cost of solar energy can be drawbacks.

1. Solar energy currently has three major disadvantages. One is that not all regions are equally sunny.

2. A second drawback is that solar energy is an intermittent resource.

3. The third disadvantage of current solar technology is the up-front cost of the equipment.

F. Solar energy is expanding.

IV.

Wind Power 1. We can harness wind power from air’s movement by using wind turbines, mechanical assemblies that convert wind’s kinetic energy, or energy of motion, into electrical energy.

A. Wind turbines convert kinetic energy to electrical energy.

1. Engineers design turbines to yaw, or rotate back and forth, in response to changes in wind direction, ensuring that the motor faces into the wind at all times.

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2. Turbines are often erected in groups; such a development is called a wind farm.

B. Wind power is growing fast.

C. Offshore sites are productive.

1. Wind speeds on average are roughly 20% greater over water than over land, and air is less turbulent over water.

D. Wind power has many benefits.

1. Like solar power, wind produces no emissions once the equipment is manufactured and installed.

2. Under optimal conditions, wind power appears efficient in its energy returned on investment.

3. Wind turbine technology can be used on many scales, from a single tower for local use to farms of hundreds that supply large regions.

4. Another benefit of wind power is that farmers and ranchers can lease their land for wind development.

5. Wind power involves up-front expenses to erect turbines and to expand infrastructure to transmit electricity, but over the lifetime of a project it requires only maintenance costs.

6. Wind power creates job opportunities.

E. Wind power has limitations.

1. Wind is an intermittent resource; we have no control over when it will occur.

2. Just as wind varies from time to time, it varies from place to place.

3. Although polls show wide public approval of existing wind projects and of the concept of wind power, newly proposed wind projects often elicit the not-in-my-backyard (NIMBY) syndrome among people living nearby.

4. Wind turbines also pose a threat to birds and bats, which are killed when they fly into the rotating blades.

V.

Geothermal Energy 1. Geothermal energy is thermal energy that arises from beneath Earth’s surface.

A. We harness geothermal energy for heating and electricity.

1. Geothermal energy can be harnessed directly from geysers at the surface, but most often wells must be drilled down hundreds or thousands of meters toward heated groundwater.

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2. Geothermal power plants harness the energy of naturally heated underground water and steam to generate electricity. Generally, a power plant brings water to temperatures of 150–370°C (300–700°F) or more to the surface and converts it to steam by lowering the pressure in specialized compartments. The steam turns turbines to generate electricity.

B. Heat pumps make use of temperatures differences.

1. Just several inches below the surface, temperatures are nearly constant year-round. Geothermal heat pumps, or ground-source heat pumps, make use of this phenomenon.

2. Ground-source heat pumps provide heating in the winter by transferring heat from the ground into buildings, and they provide cooling in the summer by transferring heat from buildings into the ground.

C. Geothermal power has pros and cons.

1. All forms of geothermal energy greatly reduce emissions relative to fossil fuel combustion.

2. In principle, geothermal energy is renewable because using it does not affect the amount of thermal energy produced underground. However, not every geothermal power plant will be able to operate indefinitely.

3. A second reason geothermal energy is not always renewable is that patterns of geothermal activity in Earth’s crust shift naturally over time.

4. The greatest limitation of geothermal power is that it is restricted to regions where we can tap energy from naturally heated groundwater.

D. Enhanced geothermal systems might widen our reach.

1. Engineers are now developing enhanced geothermal systems (EGS) in which we drill deeply into dry rock, fracture the rock, and pump in cold water. The water becomes heated deep underground and is then drawn back up and used to generate power. EGS thereby uses natural thermal energy underground but supplies the water, which can be reused repeatedly.

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VI.

Ocean Energy Sources A. We can harness energy from tides, waves, and currents.

1. Scientists and engineers are working to harness the motion of ocean waves and convert their energy into electricity. Many designs for machinery to harness wave energy have been created, but few have been thoroughly tested.

2. Wave energy is greatest on the open ocean, but transmitting electricity to shore is expensive.

3. Tidal energy can be harnessed by erecting dams across the outlets of tidal basins. The incoming tide flows through sluice gates and is trapped behind them. Then, as the outgoing tide passes through the gates, it turns turbines to generate electricity. Some designs generate electricity from water moving in both directions.

4. A third way to harness marine kinetic energy is to use the motion of ocean currents, such as the Gulf Stream. Underwater turbines have been erected in European waters to test this approach.

B. The ocean stores thermal energy.

1. The ocean’s sun-warmed surface is warmer than its deep water, and ocean thermal energy conversion (OTEC) relies on this gradient in temperature.

2. In the closed cycle approach, warm surface water is piped into a facility to evaporate chemicals, such as ammonia, that boil at low temperatures. These evaporated gases spin turbines to generate electricity. Cold water piped up from ocean depths then condenses the gases so they can be reused.

3. In the open cycle approach, warm surface water is evaporated in a vacuum and its steam turns turbines and then is condensed by cold water.

Because ocean water loses salts as it evaporates, the water can be recovered, condensed, and sold as desalinized fresh water for drinking or agriculture.

VII.

Energy Storage 1. Renewable energy can be used to generate electricity cleanly, but storing electricity cheaply and in large quantities is a challenge.

A. Batteries use chemical reactions to store energy.

1. Research and development into new and better types of batteries is active and the costs of batteries are rapidly falling.

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B. Pumped storage hydropower is our primary means of energy storage.

1. In pumped storage, water is pumped uphill from one reservoir to another when demand for electricity is low and prices are cheap, and then is allowed to flow downhill through turbines to generate electricity when demand is strong and prices are high.

C. We have a variety of other ways to store energy.

D. Hydrogen and fuel cells offer a promising avenue.

1. In such a system, electricity generated from intermittent renewable sources, such as wind or solar energy, could be used to produce hydrogen. Fuel cells—essentially hydrogen batteries—could then use hydrogen to produce electricity to power vehicles, computers, cell phones, home heating, and more.

2. Hydrogen fuel may be produced from water or from other matter.

3. Hydrogen atoms bind to other molecules, becoming incorporated in everything from water to organic molecules. In the process of electrolysis, electricity is input to split hydrogen atoms from the oxygen atoms of water molecules.

4. Once isolated, hydrogen gas can be used as a fuel to produce electricity within fuel cells. The chemical reaction involved in a fuel cell is simply the reverse of that for electrolysis.

E. Hydrogen gives us many thing to consider.

1. One major drawback of hydrogen is a lack of infrastructure to make use of it.

2. Another concern is that some research suggests that leakage of hydrogen from its production, transport, and use could potentially deplete stratospheric ozone and lengthen the atmospheric lifetime of the greenhouse gas methane.

3. Hydrogen’s benefits include the fact that we will never run out of it because it is the most abundant element in the universe.

4. Hydrogen fuel cells are energy efficient.

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Key Terms active solar energy collection concentrated solar power (CSP) electrolysis enhanced geothermal systems (EGS) feed-in tariff fuel cells geothermal energy green-collar jobs ground source heat pumps net metering not-in-my-backyard (NIMBY)

ocean thermal energy conversion (OTEC) passive solar energy collection photovoltaic (PV) cell solar energy thin-film solar cells tidal energy wave energy wind farm wind power wind turbines

Teaching Tips 1. The NEETF (National Environmental Education and Training Foundation [www.neefusa.org]) has excellent reports on the status of American knowledge about the environment, in Environmental Literacy in America: What 10 Years of NEETF/Roper Research and Related Studies Say About Environmental Literacy in the U.S. (November, 2005).

2. Discuss how electricity is generated in your region. The EPA has a “Power Profiler” program at www.epa.gov/energy that allows users to input a ZIP code to generate two charts related to energy production in their region.

3. The Database of State Incentives for Renewable Energy (DSIRE; www.dsireusa.org) is a comprehensive source of information on state, local, utility, and selected federal incentives that promote renewable energy. Have students use the website to investigate incentives that promote renewable energy in your area.

4. Discuss some actions that students can take at home, work, and school to reduce their daily energy consumption. The Department of Energy’s Office of Energy Efficiency and Renewable Energy has a web page (www.energy.gov/ eere/office-energy-efficiency-renewable-energy) with links to several pages offering energy efficiency tips.

5. Divide students into groups of no more than five members. Provide either original US Geological Survey topographic maps or downloaded maps, usually available at a state website or state geological survey office. Ask the students to do the following:

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•

Study the location of main population centers.

•

Locate major landform features such as waterways, mountains, forests, roads, population centers, and other salient features.

•

Assign students to develop a renewable energy plan for the area that takes into account the local environment, available technologies, and amenities desired by residents.

•

Have each group share their ideas with the rest of the class.

The main reason to work from topographic maps is to compel students to act with landscape “honesty,” that is, to look at the “big picture,” recognizing that decisions made in time and space should not be disconnected from the physical realities of the land.

Additional Resources Websites 1. Energy Information Administration—Renewable and Alternative Fuels, US Department of Energy (DOE) (www.eia.gov/renewable) This DOE website provides official energy statistics and information on biomass, hydro, solar, geothermal, and wind power.

2. Electricity from Nonhydroelectric Renewable Energy Sources, US Environmental Protection Agency (www.epa.gov/energy) This site features a summary of wind power, solar power, biomass, geothermal, and landfill gases in the United States as well as links to statistics about fossil fuels.

3. Energy Efficiency and Renewable Energy, US Department of Energy (www.energy.gov/eere/office-energy-efficiency-renewable-energy) A web-based energy information portal with links to many other websites and online documents about renewable energy.

4. Renewable Resource Data Center, National Renewable Energy Laboratory (www.nrel.gov/rredc) The RReDC provides information on several types of renewable energy resources in the United States through an extensive dictionary, publications, data, and maps.

5. Princeton’s Carbon Mitigation Initiative (cmi.princeton.edu) This research team presents affordable strategies for reducing carbon emissions.

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Audiovisual Materials 1. e2 Energy, 2007, distributed by PBS Distribution (www.pbs.org/e2/energy.html) Global in scope, this six-part series features viable policy and technology alternatives to the world's existing fossil fuel culture.

2. The Future Makers: Pioneering Sustainable Energy, 2009, distributed by Films Media Group (www.films.com) This program examines the work of engineering trailblazers who have made their country a world leader in green technology design. Several international case studies about the sustainable energy movement are featured in this DVD. 3. The Future of Energy, a film by Brett Mazurek, Missy Lahren, Maximilian DeArmon, and Theo Badashi, and distributed by The Video Project (www.videoproject.com) The Future of Energy illustrates that renewable power on a large scale is not just a dream, but rather a viable option already being implemented by many communities, cities, and businesses. The examples and solutions highlighted are designed to inspire others to consider adopting clean, renewable power as a smart choice with substantial economic, public health, and environmental benefits.

Weighing the Issues How to Transition to Renewable Energy?

Facts to consider: Reducing subsidies is one approach that can be taken to encourage the switch from fossil fuels to renewables. One positive aspect is that emissions would no longer be released into the environment from the extraction, refining, transportation, and use of fossil fuels. However, the cost of fossil fuels is likely to go up when the subsidies are removed. Increasing subsidies to renewable technology would be ideal, hopefully making renewables more mainstream. But who will pay for the subsidies? Carbon taxes or cap-and-trade programs will limit fossil fuel usage and put the onus of decreasing that use onto corporations or consumers.

The last method, perhaps, would be most realistic, as the country will need social buy-in to make this transition work. Additional ideas could be developed by the student, but answers will vary.

Wind and NIMBY Facts to consider: Responses will vary due to student preferences. The coal-fired plant provides a reliable source of electricity, but it burns a nonrenewable fossil fuel and pollutes the air. Wind turbines are pollution-free, but wind is an unreliable energy source that can be dangerous to migrating birds. Some people find their hardware to be aesthetically displeasing. Reaction to the erection of windmills within 338 ..

sight of houses will elicit various responses. The key to the location of a successful wind farm is to have it near constant, strong, and steady winds while at the same time minimizing the infrastructure needed to transport electricity to the regions of highest demand.

The Science behind the Story Can We Power the World with Renewable Energy?

Question: Can fossil fuels be fully replaced with renewable resources?

Study: Mark Jacobson, director of the Atmosphere/Energy Program at Stanford University, has been assessing energy sources for years with the goal of finding solutions to pollution, climate change, and energy insecurity. In 2009, he published a full lifecycle analysis of the social, health, and environmental impacts of all major energy sources and found that new renewable sources based on wind, water, and solar power were lower impact than biofuels, nuclear power, and fossil fuels.

Jacobson then teamed up with Mark Delucchi of the University of California–Davis to examine whether and how the world could meet 100% of its energy needs with clean renewable energy from the sun, wind, and water. In 2011, these researchers published a pair of scientific papers in the journal Energy Policy. In this research, Jacobson and Delucchi first calculated the likely global demand for energy in the years 2030 and 2050, using projections from the US Energy Information Administration. They then examined the current outputs and limitations of renewable energy technologies and selected those that were technically and commercially proven and established.

Results: Once all the math was done, Jacobson and Delucchi concluded that the world can, in fact, fully replace fossil fuels, nuclear power, and biofuels and meet all its energy demands with clean renewable sources alone. They proposed a quantitative breakdown of the various wind, water, and solar technologies needed to power the world in 2030. The researchers judged that a full transition was technically feasible by 2030—but because this seemed politically unlikely, they suggested producing all energy newly added between now and 2030 with renewable sources and then gradually replacing fossil fuel and nuclear power facilities with new renewables by 2050.

How Well Do Wind and Solar Complement One Another in Texas?

Observation: Wind power and solar power are intermittent energy sources.

Question: When are wind and solar energy sources available? Do they peak at different times and compensate for one another’s shortfalls?

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Study: Dr. Daniel Cohan and his undergraduate student Joanna Slusarewicz selected 12 sites across Texas (five sites with existing winds farms and seven sites with existing solar facilities). The scientists then compiled data collected by federal agencies from 2007 to 2013 on solar irradiance, wind strength, and other weather variables for the 12 sites. Cohan and Slusarewicz then analyzed how the generation of wind power and solar power varied throughout a typical 24-hour period. In addition, they analyzed seasonal patterns and reliability during peak energy demand periods.

Results: On a typical day, the two energy sources complemented one another well, with solar power peaking during the day and wind power peaking at night.

Seasonally, they found that wind sites averaged higher capacity than solar and this difference was greatest in winter and least in late summer. They also found that solar sites had high capacity factors at peak demand times in the summer, but low production in the winter. Wind sites showed the opposite pattern, with higher capacity factors at peak demand time in the winter. They concluded that in Texas, pairing wind and solar power gives quite good complementarity—when one resource goes down, the other goes up.

Local Connections Find out where your college or university gets its energy. What percentage of total energy comes from fossil fuels, and what percentages come from each type of renewable source? What percentage of electricity comes from fossil fuels, and what percentages come from each type of renewable source? Does your campus produce any solar power or wind power from panels or turbines on-site? Does it purchase renewable energy from the regional utility? Has your institution made any efforts to increase the proportion of renewable energy it buys or produces? If not, what steps do you think your school could be taking to do so?

Class time: one class period or could be completed as a homework assignment.

For some schools, this information may be available on a campus sustainability website. For other schools, students may need to contact administrators or other campus officials to learn more about campus energy use. After students research the school’s energy use, the instructor could facilitate a small group discussion or a class discussion.

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Calculating Ecological Footprints Area of photovoltaic cells

Cost of photovoltaic cells

Answers will vary depending on location

Answers will vary

A resident of Arizona

12.17 m2

$3,042

A resident of Alaska

20.86 m2

$5,214

You

1. One would need to know more details about the energy demands of that consumer and the characteristics of the roof (e.g., aspect, slope).

2. The Southwest clearly has the greatest amount of incident solar radiation per meter squared.

3. The system will eventually pay for itself in terms of avoided electricity costs. PV systems do not generate any greenhouse gases or cause other pollution during operation, and so those costs are avoided as well, even though they are hard to quantify.

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22 Managing Our Waste Chapter Objectives This chapter will help students: Summarize major approaches to managing waste, and compare and contrast the types of waste we generate Discuss the nature and scale of the waste dilemma Evaluate source reduction, reuse, composting, and recycling as approaches for reducing waste Describe landfills and incineration as conventional waste disposal methods Discuss industrial solid waste and principles of industrial ecology Assess issues in managing hazardous waste

Lecture Outline I.

Central Case Study: A Mania for Recycling on Campus A. Ed Newman of Ohio University, in Athens, Ohio, and Stacy Edmonds Wheeler of Miami University, across the state in Oxford, Ohio, challenged one another to see whose campus could recycle more in a 10-week competition. Come April, Miami University had taken the prize, recycling 41.2 pounds per student. Recyclemania was born.

B. Today, Recyclemania pits several hundred institutions against one another, involving several million students and staff across North America. The event has grown to have a board of directors and major corporate sponsors.

C. Each year, student leaders rouse their campuses to compete in two divisions and 11 different categories over eight weeks in February and March.

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D. Campuses also compete to see which can collect the most of certain types of items per person.

E. By encouraging all this recycling, Recyclemania cuts down on pollution from the mining of new resources and the manufacture of new goods.

Each year, students in the event help to prevent the release of more than 100,000 tons of carbon dioxide.

F. Recyclemania is the biggest of a growing number of campus competitions in the name of sustainability.

G. Thanks in part to Recyclemania, recycling is the most widespread activity among campus sustainability efforts.

II.

Approaches to Waste Management A. Waste refers to any unwanted material or substance that results from a human activity or process.

B. Municipal solid waste is nonliquid waste that comes from homes, institutions, and small businesses. Industrial solid waste includes waste from the production of consumer goods, mining, agriculture, and petroleum extraction and refining. Hazardous waste refers to solid or liquid waste that is toxic, chemically reactive, flammable, or corrosive.

C. There are three main components of waste management.

1. Minimizing the amount of waste we generate.

2. Recovering discarded materials and recycling them.

3. Disposing of waste safely and effectively.

D. We have several ways to reduce the amount of material in the waste stream, that is, the flow of waste as it moves from its sources toward disposal destinations. Minimizing waste at its source—called source reduction—is the preferred approach.

E. The next-best strategy in waste management is recovery, which consists of recovering, or removing, waste from the waste stream. Recovery includes recycling and composting.

1. Recycling is the process of collecting used goods and sending them to facilities that extract and reprocess raw materials that can then be used to manufacture new goods.

2. Composting is the practice of recovering organic waste (such as food and yard waste) by converting it to mulch or humus through natural biological processes of decomposition.

F. Regardless of how well we reduce our waste stream through source reduction and recovery, there will likely always be some waste left to

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dispose of. The modern waste manager attempts to follow a cradle-tocradle approach instead—one in which the materials from products are recovered and reused to create new products.

III.

Municipal Solid Waste A. Consumption leads to waste.

1. As we acquire more goods, we generate more waste. The average American generates 2.0 kg (4.4 lb) of trash per day—considerably more than people in most other industrialized nations.

2. Thanks to source reduction and reuse (especially by businesses looking to cut costs), Americans now generate slightly less waste per capita than they did in the late 1980s.

3. In developing nations, people consume fewer resources and goods, and, as a result, generate less waste.

4. Wealthier nations also can afford to invest more in waste collection and disposal, so they are often better able to manage their waste and minimize impacts on human health and the environment.

B. Reducing waste is our best option.

C. Reusing items helps reduce waste.

D. Composting recovers organic waste.

1. Composting is the conversion of organic waste into mulch or humus through natural decomposition.

E. Recycling consists of three steps.

1. The first step is to collect and process used goods and materials.

2. Items collected are taken to materials recovery facilities (MRFs), where workers and machines sort items, using automated processes including magnetic pulleys, optical sensors, water currents, and air classifiers that separate items by weight and size. The facilities clean the materials, shred them, and prepare them for reprocessing.

3. Once readied, these materials are used to manufacture new goods. If the recycling loop is to function, consumers and businesses must complete the cycle by purchasing ecolabeled products.

F. Recycling has grown rapidly.

G. The economics of recycling are complex.

1. Recycling’s growth thus far has been propelled in part by economic forces, as businesses see prospects to save money and as entrepreneurs see opportunities to start new businesses. It has also been driven by 344 ..

the desire of community and campus leaders to reduce waste and by the satisfaction people take in recycling.

2. The low commodity prices of recent years have also posed a challenge to recycling programs.

3. Recycling advocates, however, point out that market prices do not take into account external costs—in particular, the environmental and health impacts of not recycling.

4. As more manufacturers use recycled products and as more technologies and methods are developed to use recycled materials in new ways, markets should continue to expand, and new business opportunities may arise.

H. China’s new policy has upended recycling efforts.

1. In 2018, China cut back sharply on its imports of recyclable materials—particularly plastics—from other nations.

2. The main stated reason was that the materials contained so much contamination that China no longer found it economically viable to process the materials.

3. The United States does not have enough materials recovery facilities to process the recyclables, so many recyclables are being sent to the landfill.

I. Efforts to rebuild the recycling market are underway.

J. Financial incentives help address waste.

1. Waste managers offer consumers economic incentives to reduce the waste stream. In “pay-as-you-throw” garbage collection programs, municipalities charge residents for home trash pickup according to the amount of trash they put out.

2. Bottle bills are another approach hinging on financial incentives.

3. States with bottle bills now face two challenges. a. One is to amend these laws to include new kinds of containers. b. The second challenge is to adjust refunds for inflation.

K. Sanitary landfills are our main disposal method.

1. In modern sanitary landfills, waste is buried in the ground or piled up in large mounds engineered to prevent waste from contaminating the environment and threatening public health. Most municipal landfills in the United States are regulated locally or by the states, but they must meet national standards set by the EPA under the Resource Conservation and Recovery Act (RCRA), a major federal law enacted in 1976 and amended in 1984.

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2. In a sanitary landfill, waste is partially decomposed by bacteria and compresses under its own weight to take up less space. Soil is layered along with the waste to speed decomposition, reduce odor, and lessen infestation by pests. Some infiltration of rainwater into the landfill is good because it encourages biodegradation by bacteria—yet too much is not good because contaminants can escape if water carries them out.

3. Sanitary landfills also have systems of pipes, collection ponds, and treatment facilities to collect and treat leachate, liquid that results when substances from the trash dissolve in water as rainwater percolates downward.

4. Once a landfill is closed, it is capped with an engineered cover consisting of layers of plastic, gravel, and soil. Managers are required to maintain leachate collection systems for 30 years after a landfill has closed, and regulations require that groundwater be monitored regularly for contamination.

L. Incinerating trash reduces pressure on landfills.

1. Incineration, or combustion, is a controlled process in which garbage is burned at very high temperatures.

2. The ash remaining after trash is incinerated contains toxic components and therefore must be disposed of in hazardous waste landfills.

3. Most developed nations now regulate incinerator emissions, and some have banned incineration outright.

M. We can gain energy from trash.

1. Most incinerators are now waste-to-energy (WTE) facilities that use the heat produced by waste combustion to boil water, creating steam that drives electricity generation or that fuels heating systems.

2. Revenues from power generation, however, are usually not enough to offset the considerable financial cost of building and running incinerators.

3. Combustion in WTE plants is not the only way to gain energy from waste. Deep inside landfills, bacteria decompose waste in an oxygendeficient environment. This anaerobic decomposition produces landfill gas, a mix of gases roughly half of which is methane. Landfill gas can be collected, processed, and used in the same way as natural gas.

Today, hundreds of landfills are collecting landfill gas and selling it for energy.

N. We can recycle material from landfills.

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IV.

Industrial Solid Waste A. Regulation and economics each influence industrial waste generation.

1. Businesses that dispose of their own waste onsite must design and manage their landfills in ways that meet state, local, or tribal guidelines. Other businesses pay to have their waste disposed of at municipal disposal sites. Regulation varies greatly, but in most cases, state and local regulation of industrial solid waste is less strict than federal regulation of municipal solid waste.

2. The amount of waste generated by a manufacturing process is a good measure of its efficiency; the less waste produced per unit or volume of product, the more efficient that process is from a physical standpoint. However, physical efficiency is not always reflected in economic efficiency.

3. Rising costs of waste disposal enhance the financial incentive to decrease waste.

B. Industrial ecology seeks to make industry more sustainable.

1. A holistic approach that integrates principles from engineering, chemistry, ecology, and economics, industrial ecology seeks to redesign industrial systems to reduce resource inputs and to maximize both physical and economic efficiency.

2. The larger idea behind industrial ecology is that industrial systems should function more like ecological systems, in which organisms use almost everything that is produced.

3. Industrial ecologists pursue their goals in several ways: a. They examine the entire lifecycle of a given product and look for ways to make the process more efficient; this is called lifecycle analysis. b. They try to identify how waste products from one manufacturing process might be used as raw materials for another. c. They seek to eliminate environmentally harmful products and materials from industrial processes. d. They study the flow of materials through industrial systems to look for ways to create products that are more durable, recyclable, or reusable.

C. Businesses are adopting industrial ecology.

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V.

Hazardous Waste 1. By EPA definition, hazardous waste is waste that is one of the following: a. Ignitable. Likely to catch fire. b. Corrosive. Apt to corrode metals in storage tanks or equipment. c. Reactive. Chemically unstable and readily able to react with other compounds, often explosively or by producing noxious fumes. d. Toxic. Harmful to human health when inhaled, ingested, or touched.

A. Hazardous wastes are diverse.

B. Organic compounds and heavy metals pose hazards.

1. In our daily lives, we rely on synthetic organic compounds and petroleum-derived compounds to resist bacterial, fungal, and insect activity.

2. Heavy metals such as lead, chromium, mercury, arsenic, cadmium, tin, and copper are used widely in industry for wiring, electronics, metal plating, metal fabrication, pigments, and dyes.

C. E-waste has grown.

1. The amount of this electronic waste—often called e-waste—has grown rapidly and now makes up more than 1% of the US solid waste stream by weight.

2. Most electronic items we discard have ended up in conventional sanitary landfills and incinerators. However, electronic products contain heavy metals and toxic flame-retardants, and research suggests that e-waste should instead be treated as hazardous waste.

3. Increasingly, used electronics are collected by businesses, nonprofit organizations, or municipal services and are processed for reuse or recycling. There are serious concerns, however, about health risks that recycling may pose to workers doing the disassembly.

4. Another challenge is that the recent conversion of television and computer monitor technology from cathode ray tubes to LCD and plasma screens has meant that there is no longer much demand for recycled cathode ray tubes.

5. Besides keeping toxic substances out of our waste stream, e-waste recycling helps us recover rare and lucrative trace metals used in electronics. Every ounce of metal we can recycle from a manufactured item is an ounce of metal we don’t need to mine from the ground.

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D. We regulate the disposal of hazardous waste.

1. For many years, we discarded hazardous waste without special treatment. In many cases, people did not know that certain substances were harmful to human health. In other cases, it was assumed that the substances would disappear or be sufficiently diluted in the environment.

2. Many communities now designate sites or special collection days to gather household hazardous waste or designate facilities for the exchange and reuse of substances.

3. Under the Resource Conservation and Recovery Act, the EPA sets standards by which states manage hazardous waste.

4. Because current US laws make disposing of hazardous waste quite costly, irresponsible companies sometimes illegally dump waste, creating health risks for residents and financial headaches for local governments forced to deal with the mess.

5. High costs of disposal, however, have also encouraged conscientious businesses to invest in reducing their hazardous waste.

E. We use three disposal methods for hazardous waste.

1. We have developed three primary means of hazardous waste disposal: landfills, surface impoundments, and injection wells. Design and construction standards for landfills that receive hazardous waste are stricter than those for ordinary sanitary landfills.

2. Liquid hazardous waste, or waste in dissolved form, may be stored in surface impoundments, shallow depressions lined with plastic and an impervious material, such as clay.

3. In deep-well injection, a well is drilled deep beneath the water table into porous rock, and wastes are injected into it.

F. Radioactive waste is especially hazardous.

G. Contaminated sites are being cleaned up slowly.

1. Many thousands of former military and industrial sites remain contaminated with hazardous waste in the United States and virtually every other nation on Earth. Under the Superfund program administered by the EPA, experts identify sites polluted with hazardous chemicals, take action to protect groundwater near these sites, and clean up the pollution. Later laws also charged the EPA with cleaning up brownfields, lands whose reuse or development are complicated by the presence of hazardous materials.

2. Once a Superfund site has been identified, EPA scientists evaluate how near the site is to homes, whether wastes are confined or likely to 349 ..

spread, and whether the pollution threatens drinking water supplies.

Sites judged to be harmful are placed on the National Priorities List, ranked according to the risk to human health that they pose.

3. The objective of the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) was to charge the polluting parties for cleanup of their sites according to the polluterpays principle.

4. Many sites are contaminated with hazardous chemicals we have no effective way to deal with.

Key Terms bottle bills brownfields composting cradle-to-cradle deep-well injection electronic waste e-waste hazardous waste incineration industrial ecology industrial solid waste landfill gas leachate lifecycle analysis

materials recovery facilities (MRFs) municipal solid waste recovery recycling Resource Conservation and Recovery Act (RCRA) sanitary landfills source reduction Superfund surface impoundments waste waste management waste stream waste-to-energy (WTE) facility

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Teaching Tips 1. Ask students to collect household garbage (except food waste) for one week to be analyzed in class. During class time, have students separate their waste into paper, plastic, glass, metal, and other materials. What type of waste is the most abundant? What type of waste takes up the most space (i.e., has the largest volume)?

2. Use the Department of Health and Human Services’ Agency for Toxic Substances and Disease Registry (ATSDR) website (www.atsdr.cdc.gov/) to investigate the primary substances that humans were exposed to in 2005. Divide your students into groups and have them choose a substance and investigate its prevalence in your area as well as its possible effects at different exposure levels.

Have them do a poster project or a PowerPoint presentation outlining the results of their research.

3. Present the class with information about solid waste and recycling programs in your state, accessible from the EPA’s state data web page at www.epa.gov/learnissues/learn-about-waste. Have students answer these questions: How much waste is produced per person? How is the majority of waste managed? What recycling programs are in place? How successful are they?

4. Have your students set up a composting project either at your school or at a local K–12 school. Many of your students will have connections with local schools either because they attended the schools themselves or they have a family member or friend who attends or works at a school. Cornell University has guidelines for school projects at compost.css.cornell.edu/schools.html with links to articles covering the science and engineering of composting. It also has articles and videos relating to recycling and a variety of other useful links.

5. Interactions with our students are an important part of teaching that we seldom consider. Research over the past 40 years (e.g., Pygmalion in the Classroom: Teacher Expectation and Pupils’ Intellectual Development by Robert Rosenthal, 1968 and 1992; or Failing at Fairness: How Our Schools Cheat Girls by Myra and David Sadker, 1998) has looked at interactions between teachers and students at all levels, from kindergarten through law school, medical school, business school, and graduate schools in general, in all parts of the country. Some important findings noticeable at all levels were: • Male students receive attention more often and for longer periods than female students.

• Male students receive more—and more positive—feedback.

• Male students receive more specific feedback relating to their performance (e.g., a male might receive a comment about the effectiveness of his idea or an explanation that he proposed while a female student might receive a generic comment such as “good job,” or a comment about her neatness or organization).

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• The same few students are the ones asking and answering the questions for each session, and the instructor may believe, based on this small subsample, that all the students are engaged and are understanding the material.

• Students quickly pick up on negative feedback from an instructor, both verbal and nonverbal, and will refrain from further in-class interactions if they feel that they have been undervalued, disrespected, or embarrassed.

• Students quickly pick up on the tone the instructor sets for the class—whether the instructor appears accepting of a wide range of ideas or is sarcastic in remarks to some or all students. Students quickly learn whether the instructor is encouraging and willing to hear an entire idea without interruption or whether it is quickly dismissed. The students will interact with each other at or below the level set by the instructor.

• Instructors who call on students during class tend to utilize the “Teacher T”— almost exclusively calling on students who are sitting in the front row or in a central line extending perpendicularly from the first group toward the rear of the room.

The message is to be aware of your interactions with students, both verbal and nonverbal. Awareness is your first step toward improving the classroom environment.

Additional Resources Websites 1. Solid Waste, US Environmental Protection Agency (www.epa.gov/learnissues/learn-about-waste) This website provides the basic facts about the various types of solid waste (municipal, medical, hazardous, etc.) along with answers to frequently asked questions and information about types of waste, how to dispose of different types of waste, and state data on waste disposal.

2. Reduce, Reuse, Recycle, US Environmental Protection Agency (www.epa.gov/learn-issues/learn-about-waste) This EPA web page describes source reduction, ways to reuse, and recycling.

3. Solid Waste and Recycling Magazine, Business Information Group, Ontario, Canada (www.solidwastemag.com) This online Canadian bimonthly magazine provides articles about the collection, hauling, processing, and disposal of solid waste.

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4. Pollutants: Coastal Hazardous Waste Site Reports, Office of Response and Restoration, National Oceanic and Atmospheric Administration (response.restoration.noaa.gov/sitemap) This section of the NOAA Office of Response and Restoration is responsible for addressing and evaluating coastal contamination. Users have access to data sets, publications, and web portals.

5. Freecycle (www.freecycle.org) The Freecycle Network is made up of many individual groups around the world.

It is grassroots, nonprofit, and people are giving (and getting) items for free in their own areas. Each local group is moderated by a local volunteer. Membership is free. To sign up, find your community by entering it into the search box on the website.

Audiovisual Materials 1. The Clean Bin Project, 2010, a film by Grant Baldwin and Jenny Rustemeyer and distributed by The Video Project (available on Amazon.com) What would it take to live waste free? What would the impact be on the planet and on our lives? The Clean Bin Project follows a couple, Jen and Grant, as they go head to head in an uplifting and often-humorous competition to see who can produce the least amount of garbage in an entire year.

2. Here’s My Question: Where Does My Garbage Go?, 2000, produced by Middlemarch Productions and distributed by Bullfrog Films (www.bullfrogfilms.com) This film describes what happens to garbage and recyclable materials after they are collected for delivery to the landfill or to recycling centers.

3. Food Savers, 2013, distributed by Films Media Group (www.films.com) If politicians and society have already formulated a goal to stop food waste, why is it so hard to make this a reality? From a business perspective, throwing food away can pay off, despite environmental and hunger consequences. Three years after the international box office hit Taste the Waste, an investigative documentary about worldwide food waste, the same filmmaking team meets farmers, supermarket executives, cooks, design students, and citizens fighting to reduce food waste along the production and consumption chain. They also examine practical solutions and look at a diverse social movement toward a greater appreciation of food.

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Weighing the Issues Managing Waste on Campus Facts to consider: These questions require an individual response. Students will have to investigate the specific initiatives undertaken by their schools—some of which would be obvious such as placement of recycling bins or a compost bin in the cafeteria, others of which would be part of campus operations infrastructure. Major categories of waste on any college campus would be paper and electronic waste.

However, whether or not a campus is residential will dictate other major categories of waste.

Costs of Recycling and Not Recycling Facts to consider: Students should analyze many factors when answering these questions. One factor is that the recycling industry is in its infancy. As ways to utilize recycled materials are developed, markets will expand, resulting in more business opportunities as well as greater income to government recycling programs. Many lucrative businesses began as small companies or programs that ran at a loss for many years until a technological breakthrough allowed the company to prosper.

Because the world economy is just beginning to develop markets for recycled materials and products, it seems wise that governments invest in and subsidize recycling programs in order to encourage inventors to come up with more ways to utilize recycled resources.

For instance, if aluminum cans were not recycled, there would be significant economic, energy, and environmental costs in extracting, transporting, and processing bauxite (aluminum ore) to produce more new aluminum. The current consumption rate of this resource will lead to bauxite shortages in the immediate future. Another external cost that must be considered is maintaining the health of the environment. Wholesale removal of minerals from rock and soil may alter soil chemistry as well as water’s behavior in the soil, and the removal of forests will decrease the absorption of already overabundant greenhouse gases from the atmosphere.

Environmental Justice?

Facts to consider: These questions require an individual response. To answer them, students will need to gather information about their landfill locations and the demographics for neighborhoods near the landfills. Addresses for landfills and/or incinerators can be found by researching the city or county phone directories, offices, or websites. Once the students have the addresses, they will be able to use an EPA web page, the Environmental Justice Geographic Assessment Tool (www.epa.gov/environmentaljustice), to locate the facility. Demographic information, such as family income levels, is one layer that can be added on top of 354 ..

the map that shows the facility’s location. Unfortunately, the EPA mapping system does not have landfills and incinerators as part of its mapping database, so students must synthesize data from two or more sources.

The Science behind the Story Can Campus Research Help Reduce Waste?

Question: How can universities increase recycling rates on campus?

Study: Researchers in several universities across the United States have undertaken various investigations into recycling rates on their respective campuses. At the University of Washington, Dr. Jack Johnson, his students, and waste managers performed a waste audit. They sorted through the contents of trash cans, recycling bins, and compost receptacles to determine whether students were correctly sorting their waste. At Western Michigan University, Dr. Harold Glasser and his students investigated food waste in three campus dining halls. Each dining hall had a different serving strategy: one used a buffet, one used made-to-order servings, and one was trayless. Other researchers have changed the locations and signage on recycling bins and waste receptacles to investigate how to induce more people to recycle. Finally, researchers investigated whether recycling rates were affected by education (e.g., a recycling workshop).

Results: The waste audit revealed that 80% of the material thrown in the trash was actually recyclable. The food waste study showed that the trayless option resulted in the lowest rates of food waste and the buffet-style option resulted in the highest rates of food waste. Finally, researchers found that strategically locating bins can help increase recycling rates, especially if combined with an education strategy.

Local Connections On your campus, what efforts are being made to encourage recycling? Is there a composting program? How do the dining halls deal with food waste? Does the campus host any waste reduction events? Is there a student group helping address waste issues?

Consult several online sources, such as the ones discussed in this Connect and Continue section, to learn more about the wide range of activities and strategies that students, faculty, and staff are pursuing on many campuses to help reduce waste. What is being done on other campuses that your school is not doing? Describe at least three waste reduction strategies or activities you would like to see your campus pursue, and explain why. What would you need to get such an effort off the ground?

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Class time: one or more class periods or could be completed as a homework assignment.

This project could be completed individually or in small groups, although the final part might lend itself more toward small group work to allow for discussion. For some schools, campus waste management information may be available on a campus sustainability website. For other schools, students may need to contact administrators or other campus officials to learn more about campus waste management. The Connect and Continue section in the book (page 639) has resources that students can investigate to learn more about waste management on other campuses. For the last part, developing strategies for reducing waste on campus, make sure students are thinking about all aspects of their proposal (e.g., cost, logistics, school policies, etc.).

If the final products are sufficiently detailed, students could finally present their ideas to school administrators or waste management officials on campus.

Calculating Ecological Footprints Groups generating municipal solid waste

Per capita municipal solid waste generation rates US average (6.8 lb/day)

Missouri (4.50 lb/day)

Hawaii (15.5 lb/day)

Day

Year

Day

Year

Day

Year

6.8

2,482.0

4.5

1642.5

15.5

5657.5

Your class

Answers will vary

Answers will vary

Answers will vary

Answers will vary

Answers will vary

Answers will vary

Your state

Answers will vary

Answers will vary

Answers will vary

Answers will vary

Answers will vary

Answers will vary

United States

2.2 billion

812.0 billion

1.5 billion

537.0 billion

5.1 billion

1.9 trillion

World

52.4 billion

19.1 trillion

34.7 billion

13.0 trillion

119.4 billion

43.6 trillion

You

1. At the US average rate of waste production, the landfill will fill up in 16.1 years.

Missouri’s would fill up in 24.4 years.

2. 6.80/1.47 = 4.63. The average US citizen generates 4.63 times the average amount of waste of a world citizen.

3. Answers will vary.

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23 Minerals and Mining Chapter Objectives This chapter will help students: Describe the types of mineral resources and their uses Explain how minerals are processed prior to use Describe the major methods of mining Discuss the environmental and social impacts of mining Explain mine reclamation efforts and mining policy Evaluate ways to encourage sustainable use of mineral resources

Lecture Outline I.

Central Case Study: Mining for . . . Cell Phones?

A. We rely on tantalum for our cell phones, computer chips, DVD players, game consoles, and digital cameras. Tantalum powder is ideal for capacitors (the components that store energy and regulate current in miniature circuit boards) because it is highly heat-resistant and readily conducts electricity.

B. Tantalum comes from a dull blackish mineral called tantalite, which often occurs with a mineral called columbite—so the ore is referred to as columbite-tantalite, or coltan for short.

C. As information technology boomed in the late 1990s, global demand for tantalum rose and market prices for the metal shot up.

D. Most miners ended up with little while rebels, soldiers, and bandits enriched themselves selling coltan to traders, who sold it to processing companies in Asia, Europe, and the United States.

E. In 2001, an expert panel commissioned by the United Nations concluded that coltan riches were fueling, financing, and prolonging war.

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F. A 2002 peace treaty led to the withdrawal of foreign troops from the Democratic Republic of the Congo, but conflict with rebel groups within the country continues, bankrolled by the mineral riches of the region.

G. Steps are now being taken to help support legitimate Congolese mines while preventing the exploitation that has defined mining there in the recent past.

H. These efforts and others provide an opportunity to significantly reduce trade in conflict minerals while promoting trade of minerals sourced from legitimate mines in poor nations such as the Democratic Republic of the Congo.

II.

Earth’s Mineral Resources A. Rocks provide the minerals we use.

1. A rock is a solid aggregation of minerals; a mineral is a naturally occurring solid chemical element or inorganic compound with a crystal structure, a specific chemical composition, and distinct physical properties.

2. In some cases, the rock itself is a resource, such as the gravel used to make concrete. In other cases, valuable mineral resources, such as iron or phosphate, are embedded within rocks. To secure these minerals, miners remove the mineral-containing rock and then separate the desired mineral from the surrounding rock.

B. We obtain minerals by mining.

1. Mining refers to the systematic removal of rock, soil, or other material for the purpose of extracting minerals of economic interest.

C. We use mined materials extensively.

D. Metals are extracted from ores.

1. A metal is a type of chemical element, or a mass of such an element, that typically is lustrous, opaque, and malleable, and can conduct heat and electricity. Most metals are not found in a pure state in Earth’s crust, but instead are present within ore, a mineral or grouping of minerals from which we extract metals.

E. We process metals after mining ore.

1. A process known as smelting heats ore beyond its melting point and combines it with other metals or chemicals. Sometimes we mix, melt, and fuse a metal with another metal or a nonmetal substance to form an alloy.

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2. Processing metals can exert substantial environmental impacts. a. Most methods are water-intensive and energy-intensive. b. Many chemical reactions and heating processes used for extracting metals from ore emit air pollution. Smelting plants in particular have long been hotspots of toxic air pollution. c. Soil and water commonly become polluted by tailings, portions of ore left over after metals have been extracted. d. Mining operations often pump a toxic slurry of tailings into large reservoirs called surface impoundments.

F. We also mine nonmetallic minerals and fuels.

1. Sand and gravel, the most commonly mined mineral resources, are used as fill and as construction materials for the manufacturing of products such as concrete.

2. Gemstones are treasured for their rarity and beauty.

3. We also mine substances we use for fuel.

III.

Mining Methods and Their Impacts A. Strip mining removes surface layers of soil and rock.

1. When a resource occurs in shallow horizontal deposits near the surface, the most effective mining method is often strip mining, whereby layers of surface soil and rock are removed from large areas to expose the resource.

2. Strip mining can be economically efficient, but it obliterates natural communities over large areas, and the soil in refilled areas can easily erode away. Strip mining also pollutes waterways through the process of acid mine drainage, which occurs when sulfide minerals in newly exposed rock surfaces react with oxygen and rainwater to produce sulfuric acid.

B. In subsurface mining, miners work underground.

1. When a resource occurs in concentrated pockets or seams deep underground, and the earth allows for safe tunneling, then mining companies pursue subsurface mining. In this approach, shafts are excavated deep into the ground, and networks of tunnels are dug or blasted out to follow deposits of the mineral.

2. We use subsurface mining for metals such as zinc, lead, nickel, tin, gold, copper, and uranium as well as for diamonds, phosphate, salt, and potash. In addition, a great deal of coal is mined using the subsurface technique.

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3. Subsurface mining is the most dangerous form of mining and indeed one of society’s most dangerous occupations.

4. Occasionally, subsurface mines can affect people for years after they are closed. Acidic drainage can contaminate surface water and groundwater, sometimes for centuries, after mining operations cease.

Natural disasters or accidents can lead to catastrophic releases of toxin-laden waters from abandoned mines.

5. Abandoned mines can cause structural issues at the surface as well.

C. Open pit mining can create immense holes in the ground.

1. When a mineral is spread widely and evenly throughout a rock formation, or when the earth is unsuitable for tunneling, the method of choice is open pit mining. This essentially involves digging a gigantic hole and removing the desired ore along with waste rock that surrounds the ore.

2. Open pit mining is used to extract copper, iron, gold, diamonds, and coal, among other resources. We also use this technique to extract clay, gravel, sand, and stone such as limestone, granite, marble, and slate, but in these cases, we generally call these pits and quarries.

3. The sheer size of these mines means that the degree of habitat loss and aesthetic degradation is considerable. Another impact is chemical contamination from acid drainage as water runs off the waste heaps or collects in the pit.

D. Mountaintop mining reshapes ridges and can fill valleys.

1. When a resource occurs in underground seams near the tops of ridges or mountains, mining companies may practice mountaintop removal mining, in which several hundred vertical feet of mountaintop may be blasted off to allow recovery of entire seams of the resource.

2. In mountaintop removal mining, a mountain’s forests are clearcut, the timber is sold, topsoil is removed, and then rock is repeatedly blasted away to expose coal for extraction.

3. Scientists are finding that dumping tons of debris into valleys degrades or destroys immense areas of habitat, clogs streams and rivers, and pollutes waterways with acid drainage.

4. People living in communities near the mining sites experience social and health impacts.

5. Critics of mountaintop removal mining argue that valley filling violates the Clean Water Act.

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E. Placer mining uses running water to isolate minerals.

1. To search for metals and gems, miners sift through material in modern or ancient riverbed deposits, generally using running water to separate lightweight mud and gravel from heavier minerals of value. This technique is called placer mining.

2. Besides the many social and political impacts of placer mining in places such as the Democratic Republic of the Congo, placer mining is environmentally destructive because most methods wash large amounts of debris into streams, making them uninhabitable for fish and other life for many miles downstream.

F. Solution mining dissolves and extracts underground resources.

1. When a deposit is especially deep and the resource can be dissolved in a liquid, miners may use a technique called solution mining. In this technique, a narrow borehole is drilled deep into the ground to reach the deposit, and water, acid, or another liquid is injected down the borehole to leach the resource from the surrounding rock and dissolve it in the liquid. The resulting solution is then sucked out, and the desired resource can be isolated.

2. Solution mining generally exerts less environmental impact than other mining techniques because less area at the surface is disturbed.

G. Some mining occurs in the ocean.

1. The oceans hold many minerals useful to our society. The logistical difficulty of mining them, however, has kept their extraction too expensive thus far.

2. As land resources become scarcer and as undersea mining technology develops, mining companies may turn increasingly to the seas.

3. Impacts of undersea mining are largely unknown, but increases in such mining would undoubtedly destroy marine habitats and organisms that have not yet been studied. It would also likely cause some metals to diffuse into the water column at toxic concentrations and enter the food chain.

H. Restoration helps to reclaim mine sites.

1. Because of the environmental impacts of mining, governments of the United States and other developed nations now require that mining companies restore or reclaim surface-mined sites following mining.

The aim of such restoration or reclamation is to restore the site to a condition similar to its condition before mining.

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2. Even on sites that are restored, impacts from mining (such as soil and water damage from acid drainage) can be severe and long-lasting. It is difficult to regain the same biotic communities that were naturally present before mining.

3. Water polluted by mining and acid drainage can also be reclaimed if pH can be moderated and if toxic heavy metals can be removed.

I. An 1872 law still guides US mining policy.

1. The General Mining Act of 1872 encourages people and companies to prospect for minerals on federally owned land by allowing any US citizen or any company with permission to do business in the United States to stake a claim on any plot of public land open to mining.

2. The law may have made good sense in 1872, but the United States has changed a great deal since then, and many question the law’s suitability for today’s nation.

3. Critics and some legislators have tried to amend the law many times over the years, mostly without success.

4. The General Mining Act of 1872 covers a wide variety of metals, gemstones, uranium, and minerals used for building materials.

IV.

Toward Sustainable Mineral Use A. Minerals are nonrenewable resources in limited supply.

1. As minerals become scarcer, demand for them increases and their prices rise.

2. Estimates of mineral resources may increase or decrease over time due to several reasons. a. Discovery of new reserves. b. New extraction technologies. c. Changing social and technological dynamics. d. Changing consumption patterns. e. Recycling.

B. We can make our mineral use more sustainable.

1. We can recycle metals, especially from e-waste.

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Key Terms acid mine drainage alloy General Mining Act of 1872 metal mineral mining mountaintop removal mining open pit mining ore

placer mining reclamation rock smelting solution mining strip mining subsurface mining surface impoundments tailings

Teaching Tips 1. Ask students to generate a list of environmental problems and write them on the board. As a group, analyze each problem to determine how extracting natural resources affects it. For example, water quality might be impacted by the process of mountaintop removal to extract coal. Allow students to use the textbook if they need more information.

2. Have students assemble a collection of the electronic devices that they have on them. Consider calculators, cell phones, laptops, and so on. Scan the classroom for similar devices. Inventory all devices. Begin a discussion on the positive effects of those devices in their lives and list these pros in one column on the board and then the cons in another column. Expand the list to include peripheral impacts of the products. Consider the wages paid to those who mined and produced the items, and also the potential harmful effects of these items on the lives of those individuals. Also have students consider the environmental costs in terms of e-waste, the toxic waste associated with the disposal of electronic materials. After this exercise, engage the students in an environmental ethics discussion covering anthropocentric through ecocentric worldviews.

3. Most states publish a guide to the state’s geology. Some areas of North America have experienced glacial sculpting as recently as 10,000 years ago, for instance.

Other regions experienced mountain building, as in the Appalachian or Rocky Mountain regions. Have students study the processes that produced the present landforms of their state. If there are different landform regions within the same state, divide students so that there is a representative group for each region.

Challenge them to work in their groups to construct a model that they will show their classmates.

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Additional Resources Websites 1. Office of Response and Restoration, Oceanic Service, NOAA (response.restoration.noaa.gov) This website is the gateway to the NOAA department that is involved in oceanic environmental disasters, including the Exxon Valdez oil spill in Prince William Sound.

2. USGS Rocks and Images, USGS Learning Web Explorer (education.usgs.gov/secondary.html) This web reference provides an introduction to geology and descriptions of rock types.

Audiovisual Materials 1. The Hole Story: The Real Cost of Mining in Canada, 2011, video distributed by Films Media Group (www.films.com/ecTitleDetail.aspx?TitleID=26915&r=SR) Richard Desjardins and Robert Monderie make a clear case in The Hole Story against the way mining has been done in Canada. This documentary sounds the alarm about mining.

2. Rock Cycle, Scott Resources, 2005 (www.amazon.com/Rock-Cycle-DVD-ScottResources/dp/B0015J5FH8) Spectacular examples of erosion, deposition, metamorphism, and volcanism were filmed on location in the Rocky Mountains and at other locations across North America. This Rock Cycle DVD is one of the DVDs in the Scott Resources’ Earth Science series that takes a contemporary look at planet Earth, its natural resources, and the human impact on our global environment. It comes with a complete teacher’s guide including program objectives, discussion points, class activities, and a glossary.

Weighing the Issues Restoring Mined Areas Facts to Consider: Responses to these questions will vary. To require no restoration from mining companies would result in a great deal of environmental contamination and degradation, and have social and economic impacts. It would essentially represent an immense public subsidy for private companies. However, it would also be unrealistic to expect that any restoration effort after mining would ever be able to restore a mined area to its pre-mining condition. The environmental impact to soil 364 ..

and vegetation is simply too great for any ecological community to recover fully and attain its pre-mining state. Thus, the question becomes where on the continuum between no restoration and full restoration students are most comfortable.

The Science behind the Story Mapping Mountaintop Mining’s “Footprint” in Appalachia Question: Does mountaintop removal mining affect human health?

Study: To determine whether mountaintop removal mining was affecting human health, the researchers first needed to map where the mining was occurring. Because the area involved is very large, the only way to map the mining activity was using satellite imagery. The team used Google Earth and its library of Landsat satellite images to determine the areas that were undergoing active mining, the areas that were recovering from mining, and the areas that were untouched by mining from 1985– 2015. To make these determinations, the team used the data collected by the satellite in the near-infrared region and the normalized difference vegetation index (NDVI) to identify areas with vegetation that was actively photosynthesizing.

Results: The team found that from 1985–2015, a total of 2900 km2 of land was disturbed by surface mining. The data also show that active mining increased yearly from 1985–2010, but has been declining since then. Unfortunately, in 2017, funding for the study was removed by the Department of the Interior and the researchers were unable to complete the health impacts portion of the study.

Local Connections The Democratic Republic of the Congo may produce a great deal of the tantalum used in cellular phones around the world, but how do residents of D.R. Congo compare to other nations with respect to the proportion of their population that owns a cell phone? How do their usage rates compare to those in the United States and in other nations with similar or very different rates of industrialization?

Class time: minimal, could be completed as a homework assignment.

Students could complete this homework assignment using the Internet to research tantalum usage in various nations.

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Calculating Ecological Footprints Metal

Known Amount Years of economic used per economic reserves year supply left

Titanium Copper Zinc Nickel Tin Antimony Silver Gold

940,000 830,000 230,000 89,000 4700 1500 560 54

6100 21,000 13,000 2300 310 140 27 3.3

154.1 39.5 17.7 38.7 15.2 10.7 20.7 16.4

Amount used per year if everyone consumed at U.S. rate 25,558

Years of economic supply left if everyone consumed at U.S. rate 36.8

1. Lasts longest = Titanium Depleted fastest = Antimony 2. At rates in the United States: Lasts longest = Titanium Depleted fastest = Antimony 3. Answers will vary.

4. Answers will vary. Strategies will include reducing consumption, recycling resources, and reusing products containing precious metals.

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