Global Environmental Issues

A PROJECT REPORT ON

GLOBAL ENVIRONMENTAL ISSUES

SUBMITTED IN PARTIAL FULFILLMENT FOR THE AWARD OF DEGREE OF

MASTER OF SCIENCE (M.Sc.) (INDIAN INSTITUTE OF ECOLOGY AND ENVIRONMENT SIKKIM-MANIPAL UNIVERSITY, DELHI) 2008-10

BY

RANJANA G. DESHPANDE

ROLL NO. 810832241

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CHAPTER 1 OZONE DEPLETION INTRODUCTION The ozone layer protects the Earth from the ultraviolet rays sent down by the sun. If the ozone layer is depleted by human action, the effects on the planet could be catastrophic.

Ozone is present in the stratosphere. The stratosphere reaches 30 miles above the Earth, and at the very top it contains ozone. The suns rays are absorbed by the ozone in the stratosphere and thus do not reach the Earth Ozone is a bluish gas that is formed by three atoms of oxygen. The form of oxygen that humans breathe in consists of two oxygen atoms, O 2. When found on the surface of the planet, ozone is considered a dangerous pollutant and is one substance responsible for producing the greenhouse effect.The highest regions of the stratosphere contain about 90% of all ozone.

In recent years, the ozone layer has been the subject of much discussion. And rightly so, because the ozone layer protects both plant and animal life on the planet. The fact that the ozone layer was being depleted was discovered in the mid-1980s. The main cause of this is the release of CFCs, chlorofluorocarbons.

Antarctica was an early victim of ozone destruction. A massive hole in the ozone layer right above Antarctica now threatens not only that continent, but many others that could be the victims of Antarctica's melting icecaps. In the future, the ozone problem will have to be solved so that the protective layer can be conserved.

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Ozone Ozone (O3) is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic O2. Ground-level ozone is an air pollutant with harmful effects on the respiratory systems of animals. The ozone layer in the upper atmosphere filters potentially damaging ultraviolet light from reaching the Earth's surface. It is present in low concentrations throughout the Earth's atmosphere. It has many industrial and consumer applications.

Origin of ozone

Ozone-oxygen cycle in the ozone layer.

The photochemical mechanisms that give rise to the ozone layer were discovered by the British physicist Sidney Chapman in 1930. Ozone in the Earth's stratosphere is created by ultraviolet light striking oxygen molecules containing two oxygen atoms (O2), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines with unbroken O 2 to create ozone, O3. The ozone molecule is also unstable (although, in the stratosphere, long-lived) and when ultraviolet light hits ozone it splits into a molecule of O2 and an atom of atomic oxygen, a continuing process called the ozone-oxygen cycle, thus creating an ozone layer in the stratosphere, the region from about 10 to 50 km (32,000 to 164,000 feet) above Earth's surface. About 90% of the 3

ozone in our atmosphere is contained in the stratosphere. Ozone concentrations are greatest between about 20 and 40 km, where they range from about 2 to 8 parts per million. If all of the ozone were compressed to the pressure of the air at sea level, it would be only a few millimeters thick.

Structure The structure of ozone, according to experimental evidence from microwave spectroscopy, is bent, with C2v symmetry (similar to the water molecule), O – O distance of 127.2 pm and O – O – O angle of 116.78°. The central atom forms an sp² hybridization with one lone pair. Ozone is a polar molecule with a dipole moment of 0.5337 D. The bonding can be expressed as a resonance hybrid with a single bond on one side and double bond on the other producing an overall bond order of 1.5 for each side.

Chemistry Ozone is a powerful oxidizing agent, far better than dioxygen. It is also unstable at high concentrations, decaying to ordinary diatomic oxygen (in about half an hour in atmospheric conditions): 2 O 3 → 3 O2 This reaction proceeds more rapidly with increasing temperature and decreasing pressure. Deflagration of ozone can be triggered by a spark, and can occur in ozone concentrations of 10 wt% or higher.

Ozone layer 4

The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 93-99% of the sun's high frequency ultraviolet light, which is potentially damaging to life on earth. Over 91% of the ozone in Earth's atmosphere is present here. It is mainly located in the lower portion of the stratosphere from approximately 10 km to 50 km above Earth, though the thickness varies seasonally and geographically. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958 Dobson established a worldwide network of ozone monitoring stations which continues to operate today. The "Dobson unit", a convenient measure of the columnar density of ozone overhead, is named in his honor.

Ultraviolet light and ozone

Levels of ozone at various altitudes and blocking of ultraviolet radiation.

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UV-B energy levels at several altitudes. Blue line shows DNA sensitivity. Red line shows surface energy level with 10% decrease in ozone Although the concentration of the ozone in the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultraviolet (UV) radiation coming from the Sun. UV radiation is divided into three categories, based on its wavelength; these are referred to as UV-A (400-315 nm), UV-B (315-280 nm), and UV-C (280100 nm). UV-C, which would be very harmful to humans, is entirely screened out by ozone at around 35 km altitude. UV-B radiation can be harmful to the skin and is the main cause of sunburn; excessive exposure can also cause genetic damage, resulting in problems such as skin cancer. The ozone layer is very effective at screening out UVB; for radiation with a wavelength of 290 nm, the intensity at the top of the atmosphere is 350 million times stronger than at the Earth's surface. Nevertheless, some UV-B reaches the surface. Most UV-A reaches the surface; this radiation is significantly less harmful, although it can potentially cause genetic damage.

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Distribution of ozone in the stratosphere The thickness of the ozone layer—that is, the total amount of ozone in a column overhead—varies by a large factor worldwide, being in general smaller near the equator and larger towards the poles. It also varies with season, being in general thicker during the spring and thinner during the autumn in the northern hemisphere. The reasons for this latitude and seasonal dependence are complicated, involving atmospheric circulation patterns as well as solar intensity.

Since stratospheric ozone is produced by solar UV radiation, one might expect to find the highest ozone levels over the tropics and the lowest over polar regions. The same argument would lead one to expect the highest ozone levels in the summer and the lowest in the winter. The observed behavior is very different: most of the ozone is found in the mid-to-high latitudes of the northern and southern hemispheres, and the highest levels are found in the spring, not summer, and the lowest in the autumn, not winter in the northern hemisphere. During winter, the ozone layer actually increases in depth.

This puzzle is explained by the prevailing stratospheric wind patterns, known as the Brewer-Dobson circulation. While most of the ozone is indeed created over the tropics, the stratospheric circulation then transports it poleward and downward to the lower stratosphere of the high latitudes. However in the southern hemisphere, owing to the ozone hole phenomenon, the lowest amounts of column ozone found anywhere in the world are over the Antarctic in the southern spring period of September and October.

Ozone as a greenhouse gas Although ozone was present at ground level before the Industrial Revolution, peak concentrations are now far higher than the pre-industrial levels, and even background concentrations well away from sources of pollution are substantially higher. This increase in ozone is of further concern because ozone present in the upper troposphere acts as a greenhouse gas, absorbing some of the infrared energy emitted by the earth.

Quantifying the greenhouse gas potency of ozone is difficult because it is not present in uniform concentrations across the globe. However, the scientific review on the climate 7

change (the IPCC Third Assessment Report) suggests that the radiative forcing of tropospheric ozone is about 25% that of carbon dioxide.

Ozone depletion Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4% per decade in the total volume of ozone in Earth's stratosphere (ozone layer) since the late 1970s, and a much larger, but seasonal, decrease in stratospheric ozone over Earth's polar regions during the same period. The latter phenomenon is commonly referred to as the ozone hole. In addition to this well-known stratospheric ozone depletion, there are also tropospheric ozone depletion events, which occur near the surface in polar regions during spring.

Image of the largest Antarctic ozone hole ever recorded (September 2006).

The detailed mechanism by which the polar ozone holes form is different from that for the mid-latitude thinning, but the most important process in both trends is catalytic destruction of ozone by atomic chlorine and bromine. The main source of these halogen 8

atoms in the stratosphere is photodissociation of chlorofluorocarbon (CFC) compounds, commonly called freons, and of bromofluorocarbon compounds known as halons.

These compounds are transported into the stratosphere after being emitted at the surface. Both ozone depletion mechanisms strengthened as emissions of CFCs and halons increased.

CFCs and other contributory substances are commonly referred to as ozone-depleting substances (ODS). Since the ozone layer prevents most harmful UVB wavelengths (270–315 nm) of ultraviolet light (UV light) from passing through the Earth's atmosphere, observed and projected decreases in ozone have generated worldwide concern leading to adoption of the Montreal Protocol that bans the production of CFCs and halons as well as related ozone depleting chemicals such as carbon tetrachloride and trichloroethane. It is suspected that a variety of biological consequences such as increases in skin cancer, cataracts, damage to plants, and reduction of plankton populations in the ocean's photic zone may result from the increased UV exposure due to ozone depletion Ozone cycle overview Three forms (or allotropes) of oxygen are involved in the ozone-oxygen cycle: oxygen atoms (O or atomic oxygen), oxygen gas (O 2 or diatomic oxygen), and ozone gas (O 3 or triatomic oxygen). Ozone is formed in the stratosphere when oxygen molecules photodissociate after absorbing an ultraviolet photon whose wavelength is shorter than 240 nm. This produces two oxygen atoms. The atomic oxygen then combines with O 2 to create O3. Ozone molecules absorb UV light between 310 and 200 nm, following which ozone splits into a molecule of O 2 and an oxygen atom. The oxygen atom then joins up with an oxygen molecule to regenerate ozone. This is a continuing process which terminates when an oxygen atom "recombines" with an ozone molecule to make two O 2 molecules: O + O3 → 2 O2

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Global monthly average total ozone amount.

The overall amount of ozone in the stratosphere is determined by a balance between photochemical production and recombination.

Ozone can be destroyed by a number of free radical catalysts, the most important of which are the hydroxyl radical (OH·), the nitric oxide radical (NO·), atomic chlorine (Cl·) and bromine (Br·). All of these have both natural and manmade sources; at the present time, most of the OH· and NO· in the stratosphere is of natural origin, but human activity has dramatically increased the levels of chlorine and bromine. These elements are found in certain stable organic compounds, especially chlorofluorocarbons (CFCs), which may find their way to the stratosphere without being destroyed in the troposphere due to their low reactivity. Once in the stratosphere, the Cl and Br atoms are liberated from the parent compounds by the action of ultraviolet light, e.g. ('h' is Planck's constant, 'ν' is frequency of electromagnetic radiation) CFCl3 + hν → CFCl2 + Cl The Cl and Br atoms can then destroy ozone molecules through a variety of catalytic cycles. In the simplest example of such a cycle, a chlorine atom reacts with an ozone 10

molecule, taking an oxygen atom with it (forming ClO) and leaving a normal oxygen molecule. The chlorine monoxide (i.e., the ClO) can react with a second molecule of ozone (i.e., O3) to yield another chlorine atom and two molecules of oxygen. The chemical shorthand for these gas-phase reactions is: Cl + O3 → ClO + O2 ClO + O3 → Cl + 2 O2 The overall effect is a decrease in the amount of ozone. More complicated mechanisms have been discovered that lead to ozone destruction in the lower stratosphere as well.

A single chlorine atom would keep on destroying ozone (thus a catalyst) for up to two years (the time scale for transport back down to the troposphere) were it not for reactions that remove them from this cycle by forming reservoir species such as hydrogen chloride (HCl) and chlorine nitrate (ClONO2). On a per atom basis, bromine is even more efficient than chlorine at destroying ozone, but there is much less bromine in the atmosphere at present. As a result, both chlorine and bromine contribute significantly to the overall ozone depletion. Laboratory studies have shown that fluorine and iodine atoms participate in analogous catalytic cycles. However, in the Earth's stratosphere, fluorine atoms react rapidly with water and methane to form stronglybound HF, while organic molecules which contain iodine react so rapidly in the lower atmosphere that they do not reach the stratosphere in significant quantities.

Furthermore, a single chlorine atom is able to react with 100,000 ozone molecules. This fact plus the amount of chlorine released into the atmosphere by chlorofluorocarbons (CFCs) yearly demonstrates how dangerous CFCs are to the environment.

OZONE DEPLETION CAUSES: Only a few factors combine to create the problem of ozone layer depletion. The production and emission of CFCs, chlorofluorocarbons, is by far the leading cause.

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Many countries have called for the end of CFC production because only a few produce the chemical. However, those industries that do use CFCs do not want to discontinue usage of this highly valuable industrial chemical.

CFCs are used in industry in a variety of ways and have been amazingly useful in many products. Discovered in the 1930s by American chemist Thomas Midgley, CFCs came to be used in refrigerators, home insulation, plastic foam, and throwaway food containers.

Only later did people realize the disaster CFCs caused in the stratosphere. There, the chlorine atom is removed from the CFC and attracts one of the three oxygen atoms in the ozone molecule. The process continues, and a single chlorine atom can destroy over 100,000 molecules of ozone.

In 1974, Sherwood Rowland and Mario Molina followed the path of CFCs. Their research proved that CFCs were entering the atmosphere, and they concluded that 99% of all CFC molecules would end up in the stratosphere.

Only in 1984, when the ozone layer hole was discovered over Antarctica, was the proof truly conclusive. At that point, it was hard to question the destructive capabilities of CFCs. Even if CFCs were banned, problems would remain. There would still be no way to remove the CFCs that are now present in the environment. Clearly though, something must be done to limit this international problem in the future Observations on ozone layer depletion The most pronounced decrease in ozone has been in the lower stratosphere. However, the ozone hole is most usually measured not in terms of ozone concentrations at these levels (which are typically of a few parts per million) but by reduction in the total column ozone, above a point on the Earth's surface, which is normally expressed in Dobson units, abbreviated as "DU". Marked decreases in column ozone in the Antarctic spring 12

and early summer compared to the early 1970s and before have been observed using instruments such as the Total Ozone Mapping Spectrometer (TOMS).

Lowest value of ozone measured by TOMS each year in the ozone hole.

Reductions of up to 70% in the ozone column observed in the austral (southern hemispheric) spring over Antarctica and first reported in 1985 (Farman et al. 1985) are continuing. Through the 1990s, total column ozone in September and October have continued to be 40–50% lower than pre-ozone-hole values. In the Arctic the amount lost is more variable year-to-year than in the Antarctic. The greatest declines, up to 30%, are in the winter and spring, when the stratosphere is colder.

Reactions that take place on polar stratospheric clouds (PSCs) play an important role in enhancing ozone depletion. PSCs form more readily in the extreme cold of Antarctic stratosphere. This is why ozone holes first formed, and are deeper, over Antarctica.

Early models failed to take PSCs into account and predicted a gradual global depletion, which is why the sudden Antarctic ozone hole was such a surprise to many scientists.

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In middle latitudes it is preferable to speak of ozone depletion rather than holes.

Declines are about 3% below pre-1980 values for 35–60°N and about 6% for 35–60°S. In the tropics, there are no significant trends. ] Ozone depletion also explains much of the observed reduction in stratospheric and upper tropospheric temperatures. The source of the warmth of the stratosphere is the absorption of UV radiation by ozone, hence reduced ozone leads to cooling. Some stratospheric cooling is also predicted from increases in greenhouse gases such as CO2; however the ozone-induced cooling appears to be dominant.

Predictions of ozone levels remain difficult. The World Meteorological Organization Global Ozone Research and Monitoring Project - Report No. 44 comes out strongly in favor for the Montreal Protocol, but notes that a UNEP 1994 Assessment overestimated ozone loss for the 1994–1997 period Chemicals in the atmosphere CFCs in the atmosphere Chlorofluorocarbons (CFCs) were invented by Thomas Midgley in the 1920s. They were used in air conditioning/cooling units, as aerosol spray propellants prior to the 1980s, and in the cleaning processes of delicate electronic equipment. They also occur as byproducts of some chemical processes. No significant natural sources have ever been identified for these compounds — their presence in the atmosphere is due almost entirely to human manufacture. As mentioned in the ozone cycle overview above, when such ozone-depleting chemicals reach the stratosphere, they are dissociated by ultraviolet light to release chlorine atoms. The chlorine atoms act as a catalyst, and each can break down tens of thousands of ozone molecules before being removed from the stratosphere. Given the longevity of CFC molecules, recovery times are measured in decades. It is calculated that a CFC molecule takes an average of 15 years to go from the ground level up to the upper atmosphere, and it can stay there for about a century, destroying up to one hundred thousand ozone molecules during that time.

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Verification of observations Scientists have been increasingly able to attribute the observed ozone depletion to the increase of man-made (anthropogenic) halogen compounds from CFCs by the use of complex chemistry transport models and their validation against observational data (e.g.

SLIMCAT, CLaMS). These models work by combining satellite measurements of chemical concentrations and meteorological fields with chemical reaction rate constants obtained in lab experiments. They are able to identify not only the key chemical reactions but also the transport processes which bring CFC photolysis products into contact with ozone The ozone hole and its causes

Ozone hole in North America during 1984 (abnormally warm reducing ozone depletion) and 1997 (abnormally cold resulting in increased seasonal depletion).

The Antarctic ozone hole is an area of the Antarctic stratosphere in which the recent ozone levels have dropped to as low as 33% of their pre-1975 values. The ozone hole 15

occurs during the Antarctic spring, from September to early December, as strong westerly winds start to circulate around the continent and create an atmospheric container. Within this polar vortex, over 50% of the lower stratospheric ozone is destroyed during the Antarctic spring.

As explained above, the primary cause of ozone depletion is the presence of chlorinecontaining source gases (primarily CFCs and related halocarbons). In the presence of UV light, these gases dissociate, releasing chlorine atoms, which then go on to catalyze ozone destruction. The Cl-catalyzed ozone depletion can take place in the gas phase, but it is dramatically enhanced in the presence of polar stratospheric clouds (PSCs).

These polar stratospheric clouds form during winter, in the extreme cold. Polar winters are dark, consisting of 3 months without solar radiation (sunlight). The lack of sunlight contributes to a decrease in temperature and the polar vortex traps and chills air.

Temperatures hover around or below -80 °C. These low temperatures form cloud particles and are composed of either nitric acid (Type I PSC) or ice (Type II PSC). Both types provide surfaces for chemical reactions that lead to ozone destruction.

The photochemical processes involved are complex but well understood. The key observation is that, ordinarily, most of the chlorine in the stratosphere resides in stable "reservoir" compounds, primarily hydrochloric acid (HCl) and chlorine nitrate (ClONO 2).

During the Antarctic winter and spring, however, reactions on the surface of the polar stratospheric cloud particles convert these "reservoir" compounds into reactive free radicals (Cl and ClO). The clouds can also remove NO 2 from the atmosphere by converting it to nitric acid, which prevents the newly formed ClO from being converted back into ClONO2.

The role of sunlight in ozone depletion is the reason why the Antarctic ozone depletion is greatest during spring. During winter, even though PSCs are at their most abundant, there is no light over the pole to drive the chemical reactions. During the spring, however, the sun comes out, providing energy to drive photochemical reactions, and melt the polar stratospheric clouds, releasing the trapped compounds. ] 16

Most of the ozone that is destroyed is in the lower stratosphere, in contrast to the much smaller ozone depletion through homogeneous gas phase reactions, which occurs primarily in the upper stratosphere.

Warming temperatures near the end of spring break up the vortex around midDecember. As warm, ozone-rich air flows in from lower latitudes, the PSCs are destroyed, the ozone depletion process shuts down, and the ozone hole closes.

Consequences of ozone layer depletion Since the ozone layer absorbs UVB ultraviolet light from the Sun, ozone layer depletion is expected to increase surface UVB levels, which could lead to damage, including increases in skin cancer. This was the reason for the Montreal Protocol. Although decreases in stratospheric ozone are well-tied to CFCs and there are good theoretical reasons to believe that decreases in ozone will lead to increases in surface UVB, there is no direct observational evidence linking ozone depletion to higher incidence of skin cancer in human beings. This is partly due to the fact that UVA, which has also been implicated in some forms of skin cancer, is not absorbed by ozone, and it is nearly impossible to control statistics for lifestyle changes in the populace Increased UV Ozone, while a minority constituent in the Earth's atmosphere, is responsible for most of the absorption of UVB radiation. The amount of UVB radiation that penetrates through the ozone layer decreases exponentially with the slant-path thickness/density of the layer. Correspondingly, a decrease in atmospheric ozone is expected to give rise to significantly increased levels of UVB near the surface.

Increases in surface UVB due to the ozone hole can be partially inferred by radiative transfer model calculations, but cannot be calculated from direct measurements because of the lack of reliable historical (pre-ozone-hole) surface UV data, although more recent surface UV observation measurement programmes exist (e.g. at Lauder, New Zealand).

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Because it is this same UV radiation that creates ozone in the ozone layer from O 2 (regular oxygen) in the first place, a reduction in stratospheric ozone would actually tend to increase photochemical production of ozone at lower levels (in the troposphere), although the overall observed trends in total column ozone still show a decrease, largely because ozone produced lower down has a naturally shorter photochemical lifetime, so it is destroyed before the concentrations could reach a level which would compensate for the ozone reduction higher up.

Ozone depletion effects: •

Even minor problems of ozone depletion can have major effects. Every time even a small amount of the ozone layer is lost, more ultraviolet light from the sun can reach the Earth.

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Every time 1% of the ozone layer is depleted, 2% more UV-B is able to reach the surface of the planet. UV-B increase is one of the most harmful consequences of ozone depletion because it can cause skin cancer.

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The increased cancer levels caused by exposure to this ultraviolet light could be enormous. The EPA estimates that 60 million Americans born by the year 2075 will get skin cancer because of ozone depletion. About one million of these people will die.

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In addition to cancer, some research shows that a decreased ozone layer will increase rates of malaria and other infectious diseases. According to the EPA, 17 million more cases of cataracts can also be expected.

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The environment will also be negatively affected by ozone depletion. The life cycles of plants will change, disrupting the food chain. Effects on animals will also be severe, and are very difficult to foresee.

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Oceans will be hit hard as well. The most basic microscopic organisms such as plankton may not be able to survive. If that happened, it would mean that all of 18

the other animals that are above plankton in the food chain would also die out.

Other ecosystems such as forests and deserts will also be harmed.

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The planet's climate could also be affected by depletion of the ozone layer. Wind patterns could change, resulting in climatic changes throughout the world.

Biological effects The main public concern regarding the ozone hole has been the effects of of increased surface UV and microwave radiation on human health. So far, ozone depletion in most locations has been typically a few percent and, as noted above, no direct evidence of health damage is available in most latitudes. Were the high levels of depletion seen in the ozone hole ever to be common across the globe, the effects could be substantially more dramatic. As the ozone hole over Antarctica has in some instances grown so large as to reach southern parts of Australia and New Zealand, environmentalists have been concerned that the increase in surface UV could be significant.

Effects on humans UVB (the higher energy UV radiation absorbed by ozone) is generally accepted to be a contributory factor to skin cancer. In addition, increased surface UV leads to increased tropospheric ozone, which is a health risk to humans. The increased surface UV also represents an increase in the vitamin D synthetic capacity of the sunlight.

The cancer preventive effects of vitamin D represent a possible beneficial effect of ozone depletion. In terms of health costs, the possible benefits of increased UV irradiance may outweigh the burden.

1. Basal and Squamous Cell Carcinomas -- The most common forms of skin cancer in humans, basal and squamous cell carcinomas, have been strongly linked to UVB exposure. The mechanism by which UVB induces these cancers is well understood — absorption of UVB radiation causes the pyrimidine bases in the DNA molecule to form dimers, resulting in transcription errors when the DNA replicates. These cancers are 19

relatively mild and rarely fatal, although the treatment of squamous cell carcinoma sometimes requires extensive reconstructive surgery. By combining epidemiological data with results of animal studies, scientists have estimated that a one percent decrease in stratospheric ozone would increase the incidence of these cancers by 2%.

2. Malignant Melanoma -- Another form of skin cancer, malignant melanoma, is much less common but far more dangerous, being lethal in about 15% - 20% of the cases diagnosed. The relationship between malignant melanoma and ultraviolet exposure is not yet well understood, but it appears that both UVB and UVA are involved.

Experiments on fish suggest that 90 to 95% of malignant melanomas may be due to UVA and visible radiation whereas experiments on opossums suggest a larger role for UVB. Because of this uncertainty, it is difficult to estimate the impact of ozone depletion on melanoma incidence. One study showed that a 10% increase in UVB radiation was associated with a 19% increase in melanomas for men and 16% for women. A study of people in Punta Arenas, at the southern tip of Chile, showed a 56% increase in melanoma and a 46% increase in nonmelanoma skin cancer over a period of seven years, along with decreased ozone and increased UVB levels.

3. Cortical Cataracts -- Studies are suggestive of an association between ocular cortical cataracts and UV-B exposure, using crude approximations of exposure and various cataract assessment techniques. A detailed assessment of ocular exposure to UV-B was carried out in a study on Chesapeake Bay Watermen, where increases in average annual ocular exposure were associated with increasing risk of cortical opacity.

In this highly exposed group of predominantly white males, the evidence linking cortical opacities to sunlight exposure was the strongest to date. However, subsequent data from a population-based study in Beaver Dam, WI suggested the risk may be confined to men. In the Beaver Dam study, the exposures among women were lower than exposures among men, and no association was seen. Moreover, there were no data linking sunlight exposure to risk of cataract in African Americans, although other eye diseases have different prevalences among the different racial groups, and cortical opacity appears to be higher in African Americans compared with whites.

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4. Increased Tropospheric Ozone -- Increased surface UV leads to increased tropospheric ozone. Ground-level ozone is generally recognized to be a health risk, as ozone is toxic due to its strong oxidant properties. At this time, ozone at ground level is produced mainly by the action of UV radiation on combustion gases from vehicle exhausts.

Effects on crops An increase of UV radiation would be expected to affect crops. A number of economically important species of plants, such as rice, depend on cyanobacteria residing on their roots for the retention of nitrogen. Cyanobacteria are sensitive to UV light and they would be affected by its increase.

Ozone depletion and global warming Although they are often interlinked in the mass media, the connection between global warming and ozone depletion is not strong. There are five areas of linkage: Radiative forcing from various greenhouse gases and other sources.

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The same CO2 radiative forcing that produces near-surface global warming is expected to cool the stratosphere. This cooling, in turn, is expected to produce a relative increase in polar ozone (O3) depletion and the frequency of ozone holes.

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Conversely, ozone depletion represents a radiative forcing of the climate system.

There are two opposing effects: Reduced ozone causes the stratosphere to absorb less solar radiation, thus cooling the stratosphere while warming the troposphere; the resulting colder stratosphere emits less long-wave radiation downward, thus cooling the troposphere. Overall, the cooling dominates; the IPCC concludes that "observed stratospheric O3 losses over the past two decades have caused a negative forcing of the surface-troposphere system" of about −0.15 ± 0.10 watts per square meter (W/m²).

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One of the strongest predictions of the greenhouse effect is that the stratosphere will cool. Although this cooling has been observed, it is not trivial to separate the 21

effects of changes in the concentration of greenhouse gases and ozone depletion since both will lead to cooling. However, this can be done by numerical stratospheric modeling. Results from the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory show that above 20 km (12.4 miles), the greenhouse gases dominate the cooling.

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Ozone depleting chemicals are also greenhouse gases. The increases in concentrations of these chemicals have produced 0.34 ± 0.03 W/m² of radiative forcing, corresponding to about 14% of the total radiative forcing from increases in the concentrations of well-mixed greenhouse gases.

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The long term modeling of the process, its measurement, study, design of theories and testing take decades to both document, gain wide acceptance, and ultimately become the dominant paradigm. Several theories about the destruction of ozone, were hypothesized in the 1980s, published in the late 1990s, and are currently being proven. Dr Drew Schindell, and Dr Paul Newman, NASA Goddard, proposed a theory in the late 1990s, using a SGI Origin 2000 supercomputer, that modeled ozone destruction, accounted for 78% of the ozone destroyed. Further refinement of that model, accounted for 89% of the ozone destroyed, but pushed back the estimated recovery of the ozone hole from 75 years to 150 years. (An important part of that model is the lack of stratospheric flight due to depletion of fossil fuels.)

Misconceptions about ozone depletion

CFCs are "too heavy" to reach the stratosphere It is sometimes stated that since CFC molecules are much heavier than nitrogen or oxygen, they cannot reach the stratosphere in significant quantities. But atmospheric gases are not sorted by weight; the forces of wind (turbulence) are strong enough to fully intermix gases in the atmosphere. CFCs are heavier than air, but just like argon,

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krypton and other heavy gases with a long lifetime, they are uniformly distributed throughout the turbosphere and reach the upper atmosphere.

Man-made chlorine is insignificant compared to natural sources

Another objection occasionally voiced is that It is generally agreed that natural sources of tropospheric chlorine (volcanoes, ocean spray, etc.) are four to five orders of magnitude larger than man-made sources. While strictly true, tropospheric chlorine is irrelevant; it is stratospheric chlorine that affects ozone depletion. Chlorine from ocean spray is soluble and thus is washed out by rainfall before it reaches the stratosphere.

CFCs, in contrast, are insoluble and long-lived, which allows them to reach the stratosphere. Even in the lower atmosphere there is more chlorine present in the form of CFCs and related haloalkanes than there is in HCl from salt spray, and in the stratosphere halocarbons dominate overwhelmingly. Only one of these halocarbons, methyl chloride, has a predominantly natural source, and it is responsible for about 20 percent of the chlorine in the stratosphere; the remaining 80% comes from manmade compounds.

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Very large volcanic eruptions can inject HCl directly into the stratosphere, but direct measurements have shown that their contribution is small compared to that of chlorine from CFCs. A similar erroneous assertion is that soluble halogen compounds from the volcanic plume of Mount Erebus on Ross Island, Antarctica are a major contributor to the Antarctic ozone hole.

An ozone hole was first observed in 1956 G.M.B. Dobson (Exploring the Atmosphere, 2nd Edition, Oxford, 1968) mentioned that when springtime ozone levels over Halley Bay were first measured in 1956, he was surprised to find that they were ~320 DU, about 150 DU below spring levels, ~450 DU, in the Arctic. These, however, were at this time the known normal climatological values because no other antarctic ozone data were available. What Dobson describes is essentially the baseline from which the ozone hole is measured: actual ozone hole values are in the 150–100 DU range.

The discrepancy between the Arctic and Antarctic noted by Dobson was primarily a matter of timing: during the Arctic spring ozone levels rose smoothly, peaking in April, whereas in the Antarctic they stayed approximately constant during early spring, rising abruptly in November when the polar vortex broke down.

The behavior seen in the Antarctic ozone hole is distinctly different. Instead of staying constant, early springtime ozone levels suddenly drop from their already low winter values, by as much as 50%, and normal values are not reached again until December.

If the theory were correct, the ozone hole should be above the sources of CFCs CFCs are well mixed in the troposphere and the stratosphere. The reason the ozone hole occurs above Antarctica is not because there are more CFCs there but because the low temperatures due to the polar vortex allow polar stratospheric clouds to form.

There have been anomalous discoveries of significant, serious, localized "holes" above other parts of the globe.

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The "ozone hole" is a hole in the ozone layer When the "ozone hole" forms, essentially all of the ozone in the lower stratosphere is destroyed. The upper stratosphere is much less affected, however, so that the overall amount of ozone over the continent declines by 50 percent or more. The ozone hole does not go all the way through the layer; on the other hand, it is not a uniform 'thinning' of the layer either. It is a "hole" in the sense of "a hole in the ground", that is, a depression; not in the sense of "a hole in the windshield."

OZONE DEPLETION SOLUTIONS •

The discovery of the ozone depletion problem came as a great surprise. Now, action must be taken to ensure that the ozone layer is not destroyed.

•

Because CFCs are so widespread and used in such a great variety of products, limiting their use is hard. Also, since many products already contain components that use CFCs, it would be difficult if not impossible to eliminate those CFCs already in existence.

•

The CFC problem may be hard to solve because there are already great quantities of CFCs in the environment. CFCs would remain in the stratosphere for another 100 years even if none were ever produced again.

•

Despite the difficulties, international action has been taken to limit CFCs. In the Montreal Protocol, 30 nations worldwide agreed to reduce usage of CFCs and encouraged other countries to do so as well.

•

However, many environmentalists felt the treaty did "too little, too late", as the Natural Resources Defense Council put it. The treaty asked for CFC makers to only eliminate half of their CFC production, making some people feel it was inadequate.

25

•

By the year 2000, the US and twelve nations in Europe have agreed to ban all use and production of CFCs. This will be highly significant, because these countries produce three quarters of the CFCs in the world.

•

Many other countries have signed treaties and written laws restricting the use of CFCs. Companies are finding substitutes for CFCs, and people in general are becoming more aware of the dangers of ozone depletion.

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CHAPTER 2 ACID RAIN INTRODUCTION Acid rain is rain or any other form of precipitation that is unusually acidic, i.e. elevated levels of hydrogen ions (low pH). It has harmful effects on plants, aquatic animals, and infrastructure. Acid rain is mostly caused by emissions of compounds of sulfur, nitrogen, and carbon which react with the water molecules in the atmosphere to produce acids.

However, it can also be caused naturally by the splitting of nitrogen compounds by the energy produced by lightning strikes, or the release of sulfur dioxide into the atmosphere by phenomena of volcano eruptions.

Rain is slightly acidic because it contains dissolved carbon dioxide (CO2). Sulpher dioxide (SO2) and Nitrogen oxides (NOx) which are normally present in the air. Acid rain contains more acidity than the normal value because of presence of acidions due to the dissolution of these gases present in higher concentration. Acid rain, therefore, is the direct consequence of air pollution caused by gaseous emissions from industrial sources, burning of fuels (thermal plants, chimneys of brick-kilns or sugar mills.) and vehicular emissions. It is not necessary that acid rain will occur locally near the sources of air pollution. Due to the movement of air, acid rain may occur for away from the source. For instance, U.K. contributes 26% of the acidic sulpher deposited in the Netherlands, 23% in Norway and 12% in Sweden. Acid emissions arise naturally from volcanoes, forest fires and biological decomposition, especially in the oceans. But their contribution to a acid rain are SO2, NOx and to a lesser extent CO2 and HC1 gas. SO2 pollutions is mostly contributed by thermal power plants, refineries industry and NOx form road transport, power stations and industry. The acid gas concentrations in the air will vary according to location, time and weather conditions.

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DEFINITION "Acid rain" is a popular term referring to the deposition of wet (rain, snow, sleet, fog and cloudwater, dew) and dry (acidifying particles and gases) acidic components. A more accurate term is “acid deposition”.

Distilled water, which contains no carbon dioxide, has a neutral pH of 7. Liquids with a pH less than 7 are acidic, and those with a pH greater than 7 are bases. “Clean” or unpolluted rain has a slightly acidic pH of about 5.2, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid (pH 5.6 in distilled water), but unpolluted rain also contains other chemicals.

H2O (l) + CO2 (g) → H2CO3 (aq) Carbonic acid then can ionize in water forming low concentrations of hydronium and carbonate ions: 2 H2O (l) + H2CO3 (aq)

CO32− (aq) + 2 H3O+ (aq)

Acid deposition as an environmental issue would include additional acids to H2CO3.

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HISTORY Since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides to the atmosphere have increased. In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England.

Though acidic rain was discovered in 1852, it was not until the late 1960s that scientists began widely observing and studying the phenomenon. The term "acid rain" was generated in 1972. Canadian Harold Harvey was among the first to research a "dead" lake. Public awareness of acid rain in the U.S increased in the 1970s after the New York Times promulgated reports from the Hubbard Brook Experimental Forest in New Hampshire of the myriad deleterious environmental effects demonstrated to result from it.

Occasional pH readings in rain and fog water of well below 2.4 have been reported in industrialized areas. Industrial acid rain is a substantial problem in Europe, China, Russia and areas down-wind from them. These areas all burn sulfur-containing coal to generate heat and electricity. The problem of acid rain not only has increased with population and industrial growth, but has become more widespread. The use of tall smokestacks to reduce local pollution has contributed to the spread of acid rain by releasing gases into regional atmospheric circulation. Often deposition occurs a 29

considerable distance downwind of the emissions, with mountainous regions tending to receive the greatest deposition (simply because of their higher rainfall). An example of this effect is the low pH of rain (compared to the local emissions) which falls in Scandinavia.

EMISSIONS OF CHEMICALS LEADING TO ACIDIFICATION The most important gas which leads to acidification is sulfur dioxide. Emissions of nitrogen oxides which are oxidized to form nitric acid are of increasing importance due to stricter controls on emissions of sulfur containing compounds. 70 Tg(S) per year in the form of SO2 comes from fossil fuel combustion and industry, 2.8 Tg(S) from wildfires and 7-8 Tg(S) per year from volcanoes.

Natural phenomena The principal natural phenomena that contribute acid-producing gases to the atmosphere are emissions from volcanoes and those from biological processes that occur on the land, in wetlands, and in the oceans. The major biological source of sulfur containing compounds is dimethyl sulfide.

Acidic deposits have been detected in glacial ice thousands of years old in remote parts of the globe.

Human activity

30

The coal-fired Gavin Power Plant in Cheshire, Ohio The principal cause of acid rain is sulfur and nitrogen compounds from human sources, such as electricity generation, factories, and motor vehicles. Coal power plants are one of the most polluting. The gases can be carried hundreds of kilometres in the atmosphere before they are converted to acids and deposited. In the past, factories had short funnels to let out smoke, but this caused many problems locally; thus, factories now have taller smoke funnels. However, dispersal from these taller stacks causes pollutants to be carried farther, causing widespread ecological damage.

Chemical processes Combustion of fuels creates sulfur dioxide and nitric oxides. They are converted into sulfuric acid and nitric acid.

Gas phase chemistry In the gas phase sulfur dioxide is oxidized by reaction with the hydroxyl radical via an intermolecular reaction: SO2 + OH· → HOSO2· which is followed by: HOSO2· + O2 → HO2· + SO3 In the presence of water, sulfur trioxide (SO3) is converted rapidly to sulfuric acid: SO3 (g) + H2O (l) → H2SO4 (l) Nitrogen dioxide reacts with OH to form nitric acid: NO2 + OH· → HNO3

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Chemistry in cloud droplets When clouds are present, the loss rate of SO 2 is faster than can be explained by gas phase chemistry alone. This is due to reactions in the liquid water droplets.

Hydrolysis Sulfur dioxide dissolves in water and then, like carbon dioxide, hydrolyses in a series of equilibrium reactions: SO2 (g) + H2O SO2·H2O HSO3-

SO2·H2O

H+ + HSO3−

H+ + SO32−

Oxidation There are a large number of aqueous reactions that oxidize sulfur from S(IV) to S(VI), leading to the formation of sulfuric acid. The most important oxidation reactions are with ozone, hydrogen peroxide and oxygen (reactions with oxygen are catalyzed by iron and manganese in the cloud droplets).

Acid deposition Processes involved in acid deposition (SO 2 and NOx play a significant role in acid rain).

Wet deposition Wet deposition of acids occurs when any form of precipitation (rain, snow, etc.) removes acids from the atmosphere and delivers it to the Earth's surface. This can result from the deposition of acids produced in the raindrops (see aqueous phase chemistry above) or by the precipitation removing the acids either in clouds or below clouds. Wet removal of both gases and aerosols are both of importance for wet deposition.

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Dry deposition Acid deposition also occurs via dry deposition in the absence of precipitation. This can be responsible for as much as 20 to 60% of total acid deposition. This occurs when particles and gases stick to the ground, plants or other surfaces.

ADVERSE EFFECTS

Acid deposition changes the chemistry of the environment. It affects water bodies such as ponds and lakes, river and streams, and bays and estuaries by increasing their acidity, in some cases to the point where aquatic animals and plants begin to die off.

The lowered pH may liberate metals bound in the minerals of the bedrock and soils surrounding a waterbody, sometimes to a toxic effect.

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Acid deposition damages vegetation as well. Scientists have observed leaf damage attributable to acid rain that limits the plant's ability to grow and sustain itself. Damage to forests has also been well documented; acid deposition reacts chemically with forest soils, leaching away nutrients vital to tree growth while at the same time mobilizing toxic metals in the soil.

While it is less well documented, some scientists have expressed a concern that acid deposition may adversely affect land dwelling animals as well, through the mobilization of metals in drinking water and through the uptake of metals by plants that are later consumed by animals. It is likely that humans would be similarly affected. It is clear that human health is compromised in those populations chronically exposed to airborne concentrations of sulfates and nitrates found downwind of heavily industrialized areas.

Acid deposition damages man-made structures as well; limestone, marble, and sandstone are susceptible to damage from acid deposition, as are metals, paints, textiles and ceramics. Repairing the damage caused by acid rain to buildings and monuments costs millions of dollars per year.

While it is true that acid deposition is a type and consequence of air pollution, its effects are not evenly distributed. Geography, topography, meteorology, and the chemistry of soils and bedrock all play a role in what the effect of acid deposition will be. Alkaline or basic soils, for example, have some ability to resist a change in their pH due to the buffering effect of certain minerals in their makeup; less alkaline soils have less ability to resist a change. Similarly waterbodies situated on an alkaline bedrock is more resistant to lowering its pH that is less alkaline bedrock.

Distance from the source of the air pollution plays a role in the rate at which acid deposition occurs, as do prevailing wind direction and elevation. It is known for example that the eastern half of North America has been more heavily damaged by acid deposition than has the western half; it is also true that (in general) the most severe damage in the east has occurred to forests and waterbodies at higher elevations.

Clean Air Act 34

Public concern about the environment, and about air pollution as a public health issue led to the passage of the Clean Air Act in 1970. By the end of the 1980s the adverse effects of acid deposition had been so well documented that in 1990 specific amendments were added to the Clean Air Act to reduce acid deposition.

Still, there is reason to be optimistic. Studies suggest that it is possible for eco-systems damaged by acid deposition to recover. The rate at which recovery occurs and the extent to which the recovery happens is dependent upon the magnitude of the reductions in sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions, and the time it takes to achieve these emission reductions. For much of the northeastern U.S., it has been estimated that upwards to an 80 percent reduction in utility emissions of sulfur dioxide (SO2) (beyond those called for under Title IV) and the implementation of controls for nitrogen oxides (NOx) will be required for eco-system recovery. Even with these emission reductions, substantial eco-system recovery may not occur for another 25 years or more.

Critical Loads The term 'critical load' implies a tipping point, or threshold. Most generally, the critical load may be defined as the maximum load that a system can tolerate before failing. As applied to environmental issues, however, critical load usually refers to exposure to pollutants. An environmental critical load is an estimate of the level of exposure to one or more pollutants below which no harmful effects are known to occur to specified elements within an ecosystem.

The use of critical loads within the context of air quality management is premised on the notion that the effectiveness air quality policy is reflected in ecosystem impacts. The critical load concept is uniquely well suited toward informing air quality policy because its receptor-based approach takes into account both the spatial and topographical variables of atmospheric deposition. As it applies to the atmospheric deposition of acid forming compounds then, a critical load is that level of exposure to sulfur and nitrogen compounds below which no harmful effects are known to occur within a specified environment (or ecosystem). The approach used to identify critical loads for sulfur and 35

nitrogen in Maine's forest ecosystem is an ecological assessment based on an overall (steady-state) ecosystem budget for nutrient cations of calcium (Ca 2+ ), magnesium (Mg 2+ ), and potassium (K + ). This budget exists within a dynamic system of nutrient inputs, exports, and recycling.

In its simplest terms, the inputs to the nutrient budget for the Maine forest ecosystem include the addition of the nutrients Ca, Mg, and K through atmospheric deposition; acid forming compounds of sulfur (S) and nitrogen (N) are also introduced through deposition. Additional inputs of Ca, Mg, and K result from the chemical weathering of the bedrock and soils.

The overall ecosystem budget is based upon the relative values of the inputs to and exports from the system. A condition where nutrient inputs exceed exports suggests that a sufficient state of biologic capacity exists for an ecosystem. Conversely, a condition where nutrient exports exceed inputs suggests a net nutrient deficit and increasing soil acidification; conditions ultimately unsustainable for a ecosystem over the long term. Many studies have demonstrated that inadequate nutrient levels lead to poor forest health and reduced growth rates.

This chart shows that not all fish, shellfish, or the insects that they eat can tolerate the same amount of acid; for example, frogs can tolerate water that is more acidic (i.e., has a lower pH) than trout.

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Acid rain has been shown to have adverse impacts on forests, freshwaters and soils, killing insect and aquatic life-forms as well as causing damage to buildings and having impacts on human health.

EFFECTS OF ACID RAIN

The most important effects are: damage to freshwater aquatic life, damage of vegetation and damage to buildings and material.

Damage to aquatic life The main impact of fresh water acidification is a reduction in diversity and populations of fresh water species. The effect on soil and rock will depend upon the in situ capacity 37

called ‘buffering capacity’ to neutralize the acids. The soil organisms are killed in acid rain where soils have limited buffering capacity. The acidic leaf litter in forest areas adds to the nutrient leaching effects of acid rain. This scavenging from cloud increases the amount of pollution deposited. Trees are quite effective in intercepting the air borne pollutants than other types of upland vegetation. In the areas of high acid deposition and poor buffering in the lakes, a PH less than 5 has become common. At PH 5, fish life and frogs begin to disappear. By PH 4, 5, virtually all aquatic life has gone. Acid rain releases metals particularly aluminium-from the soil, which can build up in lake water to levels that are toxic to fish and other organisms. A decline in fish and amphibian population will affect the food chain of birds and mammals that depend on them for food.

Surface waters and aquatic animals Both the lower pH and higher aluminum concentrations in surface water that occur as a result of acid rain can cause damage to fish and other aquatic animals. At pHs lower than 5 most fish eggs will not hatch and lower pHs can kill adult fish. As lakes and rivers become more acidic biodiversity is reduced. Acid rain has eliminated insect life and some fish species, including the brook trout in some lakes, streams, and creeks in geographically sensitive areas, such as the Adirondack Mountains of the United States.

However, the extent to which acid rain contributes directly or indirectly via runoff from the catchment to lake and river acidity (i.e., depending on characteristics of the surrounding watershed) is variable. The United States Environmental Protection Agency's (EPA) website states: "Of the lakes and streams surveyed, acid rain caused acidity in 75 percent of the acidic lakes and about 50 percent of the acidic streams".

Damage to Trees and Plants For some years there has been concern about the apparent deterioration of trees and other vegetation. It is not easy to establish the cause of damage: pollution, drought, frost, pests and forst management methods can all affect tree health. SO2 has a direct toxic effect on trees and in parts of central Europe for example where SO2 levels are very high, extensive areas of forest have been damaged or destroyed. Acid deposition 38

may combine with other factors to affect tree health; for instance by making trees more susceptible to attack by pests, or by acidifying soils which may cause loss of essential nutrients such as magnesium, thus impairing tree growth. Nitrogen and sulphur are both plant nutrients and deposition can upset the balance of natural plant communities by encouraging the growth of other plant species. Secondary pollutants like ozone are also known to exacerbate the effects of acid deposition.

Forests and other vegetation Adverse effects may be indirectly related to acid rain, like the acid's effects on soil or high concentration of gaseous precursors to acid rain. High altitude forests are especially vulnerable as they are often surrounded by clouds and fog which are more acidic than rain.

Other plants can also be damaged by acid rain, but the effect on food crops is minimized by the application of lime and fertilizers to replace lost nutrients. In cultivated areas, limestone may also be added to increase the ability of the soil to keep the pH stable, but this tactic is largely unusable in the case of wilderness lands. When calcium is leached from the needles of red spruce, these trees become less cold tolerant and exhibit winter injury and even death.

Damage to Buildings and Materials All historic buildings suffer damage and decay with time. Natural weathering causes some of this but there is no doubt that air pollution, particularly SO2, also plays an important part. SO2 penetrated porous stones such as limestone and is converted to calcium sulphate, which causes gradual crumbling. Most building damage happens in urban areas where there are many SO2 emitters (domestic chimneys, factories and heating plant). The introduction of the Clean Air Acts and the replacement of coal fires by gas and electricity has greatly reduced sulphur dioxide levels in urban areas. Other materials badly affected by pollutant gases include marble, stained glass, most metals and paint. Poorly set or fractured concrete may also allow sulphates to penetrate and corrode the steel reinforcement inside.

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Soils Soil biology and chemistry can be seriously damaged by acid rain. Some microbes are unable to tolerate changes to low pHs and are killed. The enzymes of these microbes are denatured (changed in shape so they no longer function) by the acid. The hydronium ions of acid rain also mobilize toxins such as aluminium, and leach away essential nutrients and minerals such as magnesium.

2 H+ (aq) + Mg2+ (clay)

2 H+ (clay) + Mg2+ (aq)

Soil chemistry can be dramatically changed when base cations, such as calcium and magnesium, are leached by acid rain thereby affecting sensitive species, such as sugar maple (Acer saccharum).

Human health Scientists have suggested direct links to human health. Fine particles, a large fraction of which are formed from the same gases as acid rain (sulfur dioxide and nitrogen dioxide), have been shown to cause illness and premature deaths such as cancer and other diseases.

Other adverse effects

Effect of acid rain on statues and memorable buildings like Taj-Mahal in India Acid rain can also cause damage to certain building materials and historical monuments. This results when the sulfuric acid in the rain chemically reacts with the 40

calcium compounds in the stones (limestone, sandstone, marble and granite) to create gypsum, which then flakes off.

CaCO3 (s) + H2SO4 (aq)

CaSO4 (aq) + CO2 (g) + H2O (l)

This result is also commonly seen on old gravestones where the acid rain can cause the inscription to become completely illegible. Acid rain also causes an increased rate of oxidation for metals, and in particular copper and bronze. Visibility is also reduced by sulfate and nitrate aerosols and particles in the atmosphere.

AFFECTED AREAS Particularly badly affected places around the globe include most of Europe (particularly Scandinavia with many lakes with acidic water containing no life and many trees dead) many parts of the United States (states like New York are very badly affected) and South Western Canada. Other affected areas include the South Eastern coast of China and Taiwan.

POTENTIAL PROBLEM AREAS IN THE FUTURE Places like much of South Asia (Indonesia, Malaysia and Thailand), Western South Africa (the country), Southern India and Sri Lanka and even West Africa (countries like Ghana, Togo and Nigeria) could all be prone to acidic rainfall in the future.

REDUCING ACID POLLUTION Technical solutions In the United States, many coal-burning power plants use Flue gas desulfurization (FGD) to remove sulfur-containing gases from their stack gases. An example of FGD is the wet scrubber which is commonly used in the U.S. and many other countries. A wet scrubber is basically a reaction tower equipped with a fan that extracts hot smoke stack gases from a power plant into the tower. Lime or limestone in slurry form is also injected into the tower to mix with the stack gases and combine with the sulfur dioxide present.

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The calcium carbonate of the limestone produces pH-neutral calcium sulfate that is physically removed from the scrubber. That is, the scrubber turns sulfur pollution into industrial sulfates.

In some areas the sulfates are sold to chemical companies as gypsum when the purity of calcium sulfate is high. In others, they are placed in landfill. However, the effects of acid rain can last for generations, as the effects of pH level change can stimulate the continued leaching of undesirable chemicals into otherwise pristine water sources, killing off vulnerable insect and fish species and blocking efforts to restore native life.

Automobile emissions control reduces emissions of nitrogen oxides from motor vehicles.

Sulphur Dioxide The sulphur which is present in nearly all fossil fuels combines with oxygen when the fuel is burnt and is released into the atmosphere as SO2 gas. These emissions can be reduced by measures taken before, during, or after the combustion process.

One approach is to use fuels which naturally have little sulphur in them. The sulphur content of coal can vary considerably. Some fuels may be treated to reduce their sulphur content, but effective treatment is expensive. Demand for low sulphur fuels is increasing as more countries develop programmes to reduce sulphur pollution, so they are becoming more expensive. During combustion it is possible to reduce the eventual emissions of SO2 by the introduction of a sorbent such as limestone. The potential for sulphur reduction by this approach depends on the type of furnace or boiler. After combustion, sulphur can be removed from flue gases or ‘scrubbed’. This process is known as the flue gas desulphurization (FGD). In most FGD system a mixture of limestone and water is sprayed into the flue gas. The SO2 is converted to gypsum (calcium sulphate), which can be used in the manufacture of plaster products. However, FGD systems of this type are expensive and use considerable amounts of limestone. If all power stations were fitted with FGD, gypsum production would exceed requirements, leading to a waste disposal problem. Although such a programme would increase 42

limestone extraction by about 5%, there would be a useful reduction in gypsum quarrying. An alternative to limestone FGD systems is the regenerative FGD approach in which SO2 is captured by a substance which can be recycled. Sulphur or sulphuric acid is obtained as a by-product and can be used in the chemical industry. Again, there are limits to the amount of by-product which industry can use.

Although FGD can reduce sulphur emissions by up to 90%, such systems use extra energy and, therefore, increase emissions of the greenhouse gas CO2.

Nitrogen Oxides NOx is produced partly from the oxidation of nitrogen contained in the fuel and partly as a result of high temperature and pressure combustion, which oxidizes nitrogen in the air. Furnace burners can be changed to reduce outputs of NOx by up to 40% (low-NOx burners). NOx in flue gas can be reduced by adding ammonia and passing it over a catalyst to produce nitrogen and water. This process is called selective catalytic reduction (SCR) and can reduce NOx from combustion plant by 85%, NOx produced by cars can also be treated by using catalysts; fitting a catalytic converter to the exhaust system reduces NOx emissions by up to 90%, although it may increase emissions of CO2.

Other Options Since most acid pollution comes from burning fossil fuels, one way of reducing emissions is to reduce the overall demand for energy by encouraging energy conservation and improving the efficiency of electricity generation. Another option is to develop non-fossil fuel energy sources such as nuclear power or renewable energy (solar, wind, tidal power, etc.) However these have their own environmental problems which must be balanced against those of fossil fuels.

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International treaties A number of international treaties on the long range transport of atmospheric pollutants have been agreed e.g. Sulphur Emissions Reduction Protocol under the Convention on Long-Range Transboundary Air Pollution.

Emissions trading In this regulatory scheme, every current polluting facility is given or may purchase on an open market an emissions allowance for each unit of a designated pollutant it emits.

Operators can then install pollution control equipment, and sell portions of their emissions allowances they no longer need for their own operations, thereby recovering some of the capital cost of their investment in such equipment. The intention is to give operators economic incentives to install pollution controls.

The first emissions trading market was established in the United States by enactment of the Clean Air Act Amendments of 1990. The overall goal of the Acid Rain Program established by the Act is to achieve significant environmental and public health benefits through reductions in emissions of sulfur dioxide (SO 2) and nitrogen oxides (NOx), the primary causes of acid rain. To achieve this goal at the lowest cost to society, the program employs both regulatory and market based approaches for controlling air pollution.

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CHAPTER 3 CLIMATE CHANGE INTRODUCTION Climate change is a change in the statistical distribution of weather over periods of time that range from decades to millions of years. It can be a change in the average weather or a change in the distribution of weather events around an average (for example, greater or fewer extreme weather events). Climate change may be limited to a specific region, or may occur across the whole Earth.

In recent usage, especially in the context of environmental policy, climate change usually refers to changes in modern climate. It may be qualified as anthropogenic climate change, more generally known as global warming.

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For information on temperature measurements over various periods, and the data sources available, see temperature record. For attribution of climate change over the past century, see attribution of recent climate change.

Causes Factors that can shape climate are climate forcings. These include such processes as variations in solar radiation, deviations in the Earth's orbit, mountain-building and continental drift, and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond slowly in reaction to climate forcing because of their large mass. Therefore, the climate system can take centuries or longer to fully respond to new external forcings.

Plate tectonics Over the course of millions of years, the motion of tectonic plates reconfigures global land and ocean areas and generates topography. This can affect both global and local patterns of climate and atmosphere-ocean circulation. [1] The position of the continents determines the geometry of the oceans and therefore influences patterns of ocean circulation. The locations of the seas are important in controlling the transfer of heat and moisture across the globe, and therefore, in determining global climate. A recent example of tectonic control on ocean circulation is the formation of the Isthmus of Panama about 5 million years ago, which shut off direct mixing between the Atlantic and Pacific Oceans. This strongly affected the ocean dynamics of what is now the Gulf Stream and may have led to Northern Hemisphere ice cover. Earlier, during the Carboniferous period, plate tectonics may have triggered the large-scale storage of carbon and increased glaciation. Geologic evidence points to a "megamonsoonal" circulation pattern during the time of the supercontinent Pangaea, and climate modeling suggests that the existence of the supercontinent was conducive to the establishment of monsoons.

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More locally, topography can influence climate. The existence of mountains (as a product

of

plate

tectonics

through

mountain-building)

can

cause

orographic

precipitation. Humidity generally decreases and diurnal temperature swings generally increase with increasing elevation. Mean temperature and the length of the growing season also decrease with increasing elevation. This, along with orographic precipitation, is important for the existence of low-latitude alpine glaciers and the varied flora and fauna along at different elevations in montane ecosystems.

The size of continents is also important. Because of the stabilizing effect of the oceans on temperature, yearly temperature variations are generally lower in coastal areas than they are inland. A larger supercontinent will therefore have more area in which climate is strongly seasonal than will several smaller continents and/or island arcs.

Solar output

Variations in solar activity during the last several centuries based on observations of sunspots and beryllium isotopes.

The sun is the predominant source for energy input to the Earth. Both long- and shortterm variations in solar intensity are known to affect global climate.

Early in Earth's history the sun emitted only 70% as much power as it does today. With the same atmospheric composition as exists today, liquid water should not have existed on Earth. However, there is evidence for the presence of water on the early Earth, in the Hadean and Archean eons, leading to what is known as the faint young sun paradox.

Hypothesized solutions to this paradox include a vastly different atmosphere, with much higher concentrations of greenhouse gases than currently exist Over the following 47

approximately 4 billion years, the energy output of the sun increased and atmospheric composition changed, with the oxygenation of the atmosphere being the most notable alteration. The luminosity of the sun will continue to increase as it follows the main sequence. These changes in luminosity, and the sun's ultimate death as it becomes a red giant and then a white dwarf, will have large effects on climate, with the red giant phase possibly ending life on Earth.

Solar output also varies on shorter time scales, including the 11-year solar cycle and longer-term modulations. The 11-year sunspot cycle produces low-latitude warming and high-latitude cooling over limited areas of statistical significance in the stratosphere with an amplitude of approximately 1.5°C. But although "variability associated with the 11-yr solar cycle has a significant influence on stratospheric temperatures. ...there is still no consensus on the exact magnitude and spatial structure". These stratospheric variations are consistent with the idea that excess equatorial heating can drive thermal winds. In the near-surface troposphere, there is only a small change in temperature (on the order of a tenth of a degree, and only statistically significant in limited areas underneath the peaks in stratospheric zonal wind speed) due to the 11-year solar cycle. Solar intensity variations are considered to have been influential in triggering the Little Ice Age, and for some of the warming observed from 1900 to 1950. The cyclical nature of the sun's energy output is not yet fully understood; it differs from the very slow change that is happening within the sun as it ages and evolves, with some studies pointing toward solar radiation increases from cyclical sunspot activity affecting global warming Orbital variations Slight variations in Earth's orbit lead to changes in the seasonal distribution of sunlight reaching the Earth's surface and how it is distributed across the globe. There is very little change to the area-averaged annually-averaged sunshine; but there can be strong changes in the geographical and seasonal distrubution. The three types of orbital variations are variations in Earth's eccentricity, changes in the tilt angle of Earth's axis of rotation, and precession of Earth's axis. Combined together, these produce Milankovitch cycles which have a large impact on climate and are notable for their correlation to 48

glacial and interglacial periods, their correlation with the advance and retreat of the Sahara and for their appearance in the stratigraphic record.

Volcanism Volcanism is a process of conveying material from the crust and mantle of the Earth to its surface. Volcanic eruptions, geysers, and hot springs, are examples of volcanic processes which release gases and/or particulates into the atmosphere.

Eruptions large enough to affect climate occur on average several times per century, and cause cooling (by partially blocking the transmission of solar radiation to the Earth's surface) for a period of a few years. The eruption of Mount Pinatubo in 1991, the second largest terrestrial eruption of the 20th century (after the 1912 eruption of Novarupta) affected the climate substantially. Global temperatures decreased by about 0.5 °C (0.9 °F). The eruption of Mount Tambora in 1815 caused the Year Without a Summer. Much larger eruptions, known as large igneous provinces, occur only a few times every hundred million years, but may cause global warming and mass extinctions.

Volcanoes are also part of the extended carbon cycle. Over very long (geological) time periods, they release carbon dioxide from the Earth's crust and mantle, counteracting the uptake by sedimentary rocks and other geological carbon dioxide sinks. According to the US Geological Survey, however, estimates are that human activities generate more than 130 times the amount of carbon dioxide emitted by volcanoes.

Ocean variability

A schematic of modern thermohaline circulation 49

The ocean is a fundamental part of the climate system. Short-term fluctuations (years to a few decades) such as the El Niño–Southern Oscillation, the Pacific decadal oscillation, the North Atlantic oscillation, and the Arctic oscillation, represent climate variability rather than climate change. On longer time scales, alterations to ocean processes such as thermohaline circulation play a key role in redistributing heat by carrying out a very slow and extremely deep movement of water, and the long-term redistribution of heat in the world's oceans.

Human influences Anthropogenic factors are human activities that change the environment. In some cases the chain of causality of human influence on the climate is direct and unambiguous (for example, the effects of irrigation on local humidity), whilst in other instances it is less clear. Various hypotheses for human-induced climate change have been argued for many years. Presently the scientific consensus on climate change is that human activity is very likely the cause for the rapid increase in global average temperatures over the past several decades.[24] Consequently, the debate has largely shifted onto ways to reduce further human impact and to find ways to adapt to change that has already occurred.

Of most concern in these anthropogenic factors is the increase in CO 2 levels due to emissions from fossil fuel combustion, followed by aerosols (particulate matter in the atmosphere) and cement manufacture. Other factors, including land use, ozone depletion, animal agriculture and deforestation, are also of concern in the roles they play - both separately and in conjunction with other factors - in affecting climate, microclimate, and measures of climate variables.

Physical evidence for climatic change Evidence for climatic change is taken from a variety of sources that can be used to reconstruct past climates. Reasonably complete global records of surface temperature are available beginning from the mid-late 1800s. For earlier periods, most of the evidence is indirect—climatic changes are inferred from changes in proxies, indicators 50

that reflect climate, such as vegetation, ice cores, dendrochronology, sea level change, and glacial geology.

Historical & Archaeological evidence Climate change in the recent past may be detected by corresponding changes in settlement and agricultural patterns. Archaeological evidence, oral history and historical documents can offer insights into past changes in the climate. Climate change effects have been linked to the collapse of various civilisations.

Glaciers Glaciers are among the most sensitive indicators of climate change, advancing when climate cools (for example, during the period known as the Little Ice Age) and retreating when climate warms. Glaciers grow and shrink, both contributing to natural variability and amplifying externally forced changes. A world glacier inventory has been compiled since the 1970s. Initially based mainly on aerial photographs and maps, this compilation has resulted in a detailed inventory of more than 100,000 glaciers covering a total area of approximately 240,000 km2 and, in preliminary estimates, for the recording of the remaining ice cover estimated to be around 445,000 km2. The World Glacier Monitoring Service collects data annually on glacier retreat and glacier mass balance From this data, glaciers worldwide have been found to be shrinking significantly, with strong glacier retreats in the 1940s, stable or growing conditions during the 1920s and 1970s, and again retreating from the mid 1980s to present.[31] Mass balance data indicate 17 consecutive years of negative glacier mass balance.

Glaciers leave behind moraines that contain a wealth of material - including organic matter that may be accurately dated - recording the periods in which a glacier advanced and retreated. Similarly, by tephrochronological techniques, the lack of glacier cover can be identified by the presence of soil or volcanic tephra horizons whose date of deposit may also be precisely ascertained.

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Vegetation A change in the type, distribution and coverage of vegetation may occur given a change in the climate; this much is obvious. In any given scenario, a mild change in climate may result in increased precipitation and warmth, resulting in improved plant growth and the subsequent sequestration of airborne CO 2. Larger, faster or more radical changes, however, may well] result in vegetation stress, rapid plant loss and desertification in certain circumstances Ice cores Analysis of ice in a core drilled from a ice sheet such as the Antarctic ice sheet, can be used to show a link between temperature and global sea level variations. The air trapped in bubbles in the ice can also reveal the CO 2 variations of the atmosphere from the distant past, well before modern environmental influences. The study of these ice cores has been a significant indicator of the changes in CO 2 over many millennia, and continue to provide valuable information about the differences between ancient and modern atmospheric conditions.

Dendroclimatology Dendroclimatology is the analysis of tree ring growth patterns to determine past climate variations. Wide and thick rings indicate a fertile, well-watered growing period, whilst thin, narrow rings indicate a time of lower rainfall and less-than-ideal growing conditions.

Pollen analysis Palynology is the study of contemporary and fossil palynomorphs, including pollen.

Palynology is used to infer the geographical distribution of plant species, which vary under different climate conditions. Different groups of plants have pollen with distinctive shapes and surface textures, and since the outer surface of pollen is composed of a very resilient material, they resist decay. Changes in the type of pollen found in different

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sedimentation levels in lakes, bogs or river deltas indicate changes in plant communities; which are dependent on climate conditions.

Insects Remains of beetles are common in freshwater and land sediments. Different species of beetles tend to be found under different climatic conditions. Given the extensive lineage of beetles whose genetic makeup has not altered significantly over the millennia, knowledge of the present climatic range of the different species, and the age of the sediments in which remains are found, past climatic conditions may be inferred.

Sea level change Global sea level change for much of the last century has generally been estimated using tide gauge measurements collated over long periods of time to give a long-term average. More recently, altimeter measurements — in combination with accurately determined satellite orbits — have provided an improved measurement of global sea level change.

COPENHAGEN CLIMATE COUNCIL The Copenhagen Climate Council is a global collaboration between international business and science founded by the leading independent think tank in Scandinavia, Monday Morning, based in Copenhagen. The councilors of the Copenhagen Climate Council have come together to create global awareness of the importance of the UN Climate Summit (COP15) in Copenhagen, December 2009, and to ensure technical and public support and assistance to global decision makers when agreeing on a new climate treaty to replace the Kyoto Protocol from 1997.

Organization The Copenhagen Climate Council was founded in 2007 by Erik Rasmussen, Founder, Copenhagen Climate Council; CEO and Editor-in-Chief in Scandinavia, Monday Morning, head-quartered in Copenhagen, Denmark.

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Purpose The purpose of the Copenhagen Climate Council is to create global awareness of the importance of the UN Climate Summit (COP15) in Copenhagen, December 2009.

Leading up to this pivotal UN meeting, the Copenhagen Climate Council works on presenting innovative yet achievable solutions to climate change, as well as assess what is required to make a new global treaty effective. The Council will seek to promote constructive dialogue between government and business, so that when the world's political leaders and negotiators meet in Copenhagen, they will do so armed with the very best arguments for establishing a treaty that can be supported by global business.

By promoting and demonstrating innovative, positive, and meaningful business leadership and ideas, the Copenhagen Climate Council aims to demonstrate that achieving an effective global climate treaty is not only possible, but necessary. The strategy is built upon the following principles: •

Creating international awareness of the importance of the Copenhagen UN Climate Summit and the successor treaty to the Kyoto Protocol.

•

Promoting constructive dialogue between government, business, and science.

•

Inspiring global business leaders by demonstrating that tackling climate change also has the potential to create huge opportunities for innovation and economic growth.

Membership Copenhagen Climate Council comprises 30 global climate leaders representing business, science, and public policy from all parts of the world.

•

Business leaders are selected to represent global companies and innovative entrepreneurs, who, through their actions, reveal that sustainable, climateresponsible business is both necessary and profitable.

•

Scientists are gathered to ensure that the work of the Council is underpinned by rigorous analysis.

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•

Policy makers with experience in public policy are included in the Council to ensure that the work is informed by knowledge of what is required to assist highlevel, complex policy negotiations.

Activities The central aim of the Copenhagen Climate Council is to create global awareness to the urgency of reaching a global agreement on how to tackle climate change at the UN Climate Conference in Copenhagen, December 2009. To achieve this end, the Copenhagen Climate Council provides a Web 2.0 climate website – 'The Climate Community' – which features latest climate news, intelligence, solutions and points of view, an online climate community, as well as the rest of the Copenhagen Climate Council activities, such as the 'World Business Summit on Climate Change'; launching the 'Thought Leadership Series'; launching the 'Climate LIFE' film, book, and digital exhibition; co-hosting with CITRIS the scientific conference 'Unlocking the Climate Code: Innovation in Climate and Energy'; and the Poznan side event 'Business Requirements of a Post-2012 Climate Treaty'. Recently, the Copenhagen Climate Council has also hosted a Business Roundtable in Beijing.

The Climate Community The Climate Community is the official website of the Copenhagen Climate Council. The website is based on Web 2.0 principles, and hooks the user up with the worlds leading climate stakeholders and offers possibility for the user to give voice and influence the global climate agenda. The Climate Community aims to bring the latest and most relevant news, insights, and intelligence that equips the user to navigate the climate challenges and turn risks into opportunities. The Climate Community features an extensive news section with Top Stories, Daily News Summaries, Points of Views, and a Weekly Roundup, searchable by date, region and sector.

Exclusive news features so far include interviews with U.S. Energy Secretary Steve Chu, UN Climate Chief Yvo de Boer, the Danish Climate minister Connie Hedegaard, IPCC Chairman Rajendra Pachauri, Professor Daniel Kammen, Lars Josefsson, CEO of 55

Vattenfall. The Climate Community also features regular updates on the COP15 negotiation process and important upcoming events. The unique content on Community also includes selected and in-depth descriptions of innovative business solutions. A valuable feature on the Community is the Climate Intelligence Archive, which selects and list key international policies, research reports, government agencies, NGOs, inspiring media sources, and upcoming climate events.

The Climate Community also hosts an online Virtual Summit, which is an integral part of the World Business Summit on Climate Change to take place in May 2009. The Virtual Summit will facilitate knowledge sharing and collaboration, as well as be a testing ground for new ideas and partnerships through interactive web 2.0 tools.

World Business Summit on Climate Change The World Business Summit on Climate Change takes place six months prior to the pivotal UN climate change conference (COP15) in Copenhagen, December 2009. The summit brings together business chief executives with the world's top scientists, economists, civil society, media leaders, government representatives and other leading thinkers to put forward recommendations for the next international framework on climate change to replace the Kyoto Protocol after 2012. Among the prominent participants so far are Al Gore, Chairman of Generation Investment Management; Anders Fogh Rasmussen, Prime Minister of Denmark; and Sir Richard Branson, Founder and CEO of the Virgin Group.

At the summit, chief executives will discuss how business can help solve the climate crisis through innovative business models, new partnerships and the development of low carbon technologies. They will send a message to the negotiating governments on how to remove barriers and create incentives for implementation of new solutions in a post-Kyoto. The results of the World Business Summit on Climate Change will be presented to the Danish government, host of COP15, and to world leaders negotiating the terms of the next international climate treaty.

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The LIFE Digital exhibition The LIFE digital Exhibition is intended to demonstrate what makes Climate LIFE possible. When launched on the web, it will explore the delivery model necessary to achieve the vision of Climate LIFE. Looking at the political, economic and cultural systems as well as the technological and biological process that will underpin low carbon living in the future, the exhibition will present a variety of practical solutions and their implications, highlighting the state of the art in movement, energy production and efficient consumption, water and waste management etc. The exhibition aims to use the latest social software advances and interactive tools to illustrate the challenges, how they affect people, and the possibilities for getting involved.

Business Requirements of a Post-2012 Climate Treaty On December 8, 2008, the Copenhagen Climate Council hosted an official side event at the UN COP14 Summit on Climate Change in Poznan, Poland from December 1-10, 2008. The theme was Business Requirements to a Post-2012 Climate Treaty. At the event, Council representatives from business and science presented their key principles for a new treaty. The thoughts presented at the event will feed into the development of the final recommendations delivered by international business leaders at the World Business Summit on Climate Change, to be held in Copenhagen in May, 2009.

The speakers delivered their views on what they would toast to in Copenhagen. They included: Copenhagen Climate Council Chairman Tim Flannery; Robert Purves from World Wildlife Fund International; Jerry Stokes, president of Suntech Europe; Dr. Zhengrong Shi, Founder and CEO of Suntech; Steve Harper of Intel; Susanne Stormer from Novo Nordisk; Michael Zarin of Vestas; and Thomas Becker, the lead climate negotiator for the Danish government that will host the UN COP15 climate summit in December, 2009. The session was moderated by Nick Rowley, strategic director at Copenhagen Climate Council.

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2009 UNITED NATIONS CLIMATE CHANGE CONFERENCE

United Nations Climate Change Conference (COP15)

INTRODUCTION 58

The 2009 United Nations Climate Change Conference was held at the Bella Center in Copenhagen, Denmark, between 7 December and 18 December. The conference included the 15th Conference of the Parties (COP 15) to the United Nations Framework Convention on Climate Change and the 5th Meeting of the Parties (COP/MOP 5) to the Kyoto Protocol. According to the Bali Road Map, a framework for climate change mitigation beyond 2012 was to be agreed there.

The conference was preceded by the Climate Change: Global Risks, Challenges and Decisions scientific conference, which took place in March 2009 and was also held at the Bella Center. The negotiations began to take a new format when in May 2009 UN Secretary General Ban-Ki Moon attended the World Business Summit on Climate Change in Copenhagen, organised by the Copenhagen Climate Council (COC), where he requested that COC councillors attend New York's Climate Week at the Summit on Climate Change on 22 September and engage with heads of government on the topic of the climate problem.

Connie Hedegaard was president of the conference until December 16, 2009, handing over the chair to Danish Prime Minister Lars Løkke Rasmussen in the final stretch of the conference, during negotiations between heads of state and government. On Friday 18 December, the final day of the conference, international media reported that the climate talks were "in disarray". Media also reported that in lieu of a summit collapse, solely a "weak political statement" was anticipated at the conclusion of the conference.

The Copenhagen Accord was drafted by the US, China, India, Brazil and South Africa on December 18, and judged a "meaningful agreement" by the United States government. It was "recognised", but not "agreed upon", in a debate of all the participating countries the next day, and it was not passed unanimously. The document recognised that climate change is one of the greatest challenges of the present and that actions should be taken to keep any temperature increases to below 2°C. The document is not legally binding and does not contain any legally binding commitments for reducing CO2 emissions.Leaders of industrialised countries, including Barack

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Obama and Gordon Brown, were pleased with this agreement but many leaders of other countries and non-governmental organisations were opposed to it.

Background and lead-up Negotiating position of the European Union On 28 January 2009, the European Commission released a position paper, "Towards a comprehensive climate agreement in Copenhagen."The position paper "addresses three key challenges: targets and actions; financing [of "low-carbon development and adaptation"]; and building an effective global carbon market".

In order to demonstrate good example, the European Union had committed to implementing binding legislation, even without a satisfactory deal in Copenhagen. Last December, the European Union revised its carbon allowances system called the Emissions Trading Scheme (ETS) designed for the post-Kyoto period (after 2013). This new stage of the system aims at further reducing greenhouse gases emitted in Europe in a binding way and at showing the commitments the EU had already done before the Copenhagen meeting. To avoid carbon leakage—relocation of companies in other regions not complying with similar legislation—the EU Commission will foresee that sectors exposed to international competition, should be granted some free allocations of CO2 emissions provided that they are at least at the same level of a benchmark. Other sectors should buy such credits on an international market. Energy intensive industries in Europe have advocated for this benchmark system in order to keep funds in investment capacities for low carbon products rather than for speculations. The European chemical industry claims here the need to be closer to the needs of citizens in a sustainable way. To comply with such commitments for a low-carbon economy, this requires competitiveness and innovations.

The French Minister for Ecology Jean-Louis Borloo pushes the creation of the Global Environment Organisation as France's main institutional contribution, to offer a powerful alternative to the UNEP. 60

Official pre-Copenhagen negotiation meetings A draft negotiating text for finalisation at Copenhagen has been publicly released. It is being discussed at a series of meetings before Copenhagen.

Bonn – second negotiating meeting Delegates from 183 countries met in Bonn from 1 to 12 June 2009. The purpose was to discuss key negotiating texts. These will serve as the basis for the international climate change agreement at Copenhagen. At the conclusion the Ad Hoc Working Group under the Kyoto Protocol (AWG-KP) negotiating group was still far away from the emission reduction range that has been set out by science to avoid the worst ravages of climate change: a minus 25% to minus 40% reduction below 1990 levels by 2020. The AWGKP still needs to decide on the aggregate emission reduction target for industrialised countries, along with individual targets for each country. Progress was made in gaining clarification of the issues of concern to parties and including these concerns in the updated draft of the negotiating text.

Seventh session Bangkok The first part of the seventh session of the AWG-LCA was held in Bangkok, Thailand, from Monday, 28 September at the United Nations Conference Centre (UNCC) of the United Nations Economic and Social Commission for Asia and the Pacific (UNESCAP), Bangkok, Thailand.

Barcelona The resumed session was held in Barcelona, Spain, from 2 to 6 November 2009.

Thereafter, the AWG-LCA will meet to conclude its work at its eighth session, concurrently with the fifteenth session of the Conference of the Parties which opened in Copenhagen on 7 December 2009.

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Listing of proposed actions Proposed changes in absolute emissions

Area

1990→2020 Reference base

Japan

−25%

EU

−20 to −30%

Russia

−20 to −25%

South Africa −18%

New Zealand −10 to −20%

Australia

−4 to −24% CO2-e w/- LULUCF

Canada

−3%

United States

Brazil

−1.3%

+5 to −1.8%

During the conference some countries stated what actions they were proposing to take if a binding agreement was achieved. In the end, no such agreement was reached and the actions will instead be debated in 2010. Listing by country or political union.

Sections in alphabetic order, table according to higher objectives.

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Australia To cut carbon dioxide emissions by 25% below 2000 levels by 2020 if the world agrees to an ambitious global deal to stabilise levels of CO2e to 450 ppm or lower.

To cut carbon dioxide emissions by 15% below 2000 levels by 2020 if there is an agreement where major developing economies commit to substantially restrain emissions and advanced economies take on commitments comparable to Australia.

To cut carbon dioxide emissions by 5% below 2000 levels by 2020 unconditionally.

It is clearly stated in proceedings from the Australian Senate and policy statements from the government that the Australian emission reductions include land use, land-use change and forestry (LULUCF) with the form of inclusion remaining undecided and whilst acknowledging that they are subject to the forming of accounting guidelines from this Copenhagen conference. In contention is the Australian Government's preference for the removal of non-human induced LULUCF emissions – and perhaps their abatement – from the account, such as from lightning induced bushfires and the subsequent natural carbon sequestering regrowth.

Using Kyoto accounting guidelines, these proposals are equivalent to an emissions cut of 24%, 14%, and 4% below 1990 levels by 2020 respectively. Raw use of UNFCCC CO2e data including LULUCF as currently defined by the UNFCCC for the years 2000 (404.392 Tg CO2e) and 1990 (453.794 Tg CO2e) leads to apparent emissions cuts of 33% (303.294 Tg CO2e), 25% (343.733 Tg CO2e) and 15% (384.172 Tg CO2e) respectively.

Brazil To cut emissions by 38–42% below projected 2020 levels by that same year.

This is equivalent to a change to emissions to between 5% above and 1.8% below 1990 levels by 2020.

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Canada To cut carbon emissions by 20% below 2006 levels by 2020. This is equivalent to 3% below 1990 levels by 2020.

The three most populous provinces disagree with the federal government goal and announced more ambitious targets on their jurisdictions. Quebec, Ontario and British Columbia announced respectively 20%, 15% and 14% reduction target below their 1990 levels while Alberta is expecting a 58% increase in emissions.

China To cut emissions intensity by 40–45% below 2005 levels by 2020.

European Union To cut greenhouse gas emissions by 30% below 1990 levels by 2020 if an international agreement is reached committing other developed countries and the more advanced developing nations to comparable emission reductions.

To cut greenhouse gas emissions by 20% below 1990 levels by 2020 unconditionally.

India To cut emissions intensity by 20–25% below 2005 levels by 2020.

Japan To cut greenhouse gas emissions by 25% below 1990 levels by 2020.

New Zealand To reduce emissions between 10% to 20% below 1990 levels by 2020 if a global agreement is secured that limits carbon dioxide equivalent (CO 2-e) to 450 ppm and

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temperature increases to 2°C, effective rules on forestry, and New Zealand having access to international carbon markets.

Russia To reduce emissions between 20% to 25% below 1990 levels by 2020 if a global agreement is reached committing other countries to comparable emission reductions.

Singapore To reduce emissions by 16% by 2020, based on business-as-usual levels.

South Africa To cut emissions by 34% below current levels by 2020. This is equivalent to an absolute emissions cut of 18% below 1990 levels by 2020.

United States of America To cut greenhouse gas emissions by 17% below 2005 levels by 2020, 42% by 2030 and 83% by 2050. This is equivalent to 1.3% below 1990 levels by 2020, 31% by 2030 and 80% by 2050.

Technology measures UNEP At the fifth Magdeburg Environmental Forum held from 3 to 4 July 2008, in Magdeburg, Germany, United Nations Environment Programme called for the establishment of infrastructure for electric vehicles. At this international conference, 250 high-ranking representatives from industry, science, politics and non-government organizations discussed solutions for future road transportation under the motto of "Sustainable Mobility– United Nations Climate Change Conference 2009|the Post-2012 CO2 Agenda".

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Technology Action Programs Technology Action Programs (TAPs) have been proposed as a means for organizing future technology efforts under the UNFCCC. By creating programs for a set of adaptation and mitigation technologies, the UNFCCC would send clear signals to the private and finance sector, governments, research institutions as well as citizens of the world looking for solutions to the climate problem. Potential focus areas for TAPs include early warning systems, expansion of salinity-tolerant crops, electric vehicles, wind and solar energy, efficient energy grid systems, and other technologies.

Technology roadmaps will address barriers to technology transfer, cooperative actions on technologies and key economic sectors, and support implementation of Nationally Appropriate Mitigation Actions (NAMAs) and National Adaptation Programmes of Action (NAPAs).

Side Event on Technology Transfer The United Nations Industrial Development Organisation (UNIDO) and the Department of Economic and Social Affairs (UNDESA) have been assigned the task of coconvening a process to support UN system-wide coherence and international cooperation on climate change-related technology development and transfer. This COP15 Side Event will feature statements and input from the heads of UNDESA, UNDP, GEF, WIPO, UNIDO, UNEP, IRENA as well as the UN Foundation. Relevant topics such as the following will be among the many issues discussed: •

Technology Needs Assessments (TNA)

•

The Poznan Strategic Programme on Technology Transfer

•

UN-ENERGY

•

Regional Platforms and Renewable Energy Technologies

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Related public actions The Danish government and key industrial organizations have entered a public-private partnership to promote Danish cleantech solutions. The partnership, Climate Consortium Denmark, is an integrated part of the official portfolio of activities before, during and after the COP15.

There is also a European Conference for the Promotion of Local Actions to Combat Climate Change. The entire morning session on 25 September was devoted to the Covenant of Mayors.

The Local Government Climate Lounge will be an advocacy and meeting space located directly in the COP 15 building, at the heart of the negotiations.

Outcome On December 18 after a day of frantic negotiations between heads of state, it was announced that a "meaningful agreement" had been reached between the United States, China, India, South Africa, and Brazil. The use of "meaningful" was viewed as being political spin by an editorial in The Guardian. An unnamed US government official was reported as stating that the deal was a "historic step forward" but was not enough to prevent dangerous climate change in the future. However, the BBC's environment correspondent stated: "While the White House was announcing the agreement, many other – perhaps most other – delegations had not even seen it. A comment from a UK official suggested the text was not yet final and the Bolivian delegation has already complained about the way it was reached – 'anti-democratic, anti-transparent and unacceptable'. With no firm target for limiting the global temperature rise, no commitment to a legal treaty and no target year for peaking emissions, countries most vulnerable to climate impacts have not got the deal they wanted."

Early on Saturday 19 December, delegates approved a motion to "take note of the Copenhagen Accord of December 18, 2009". However it was reported that it was not yet clear whether the motion was unanimous, or what its legal implications are. The UN 67

Secretary General Ban Ki-moon welcomed the US-backed climate deal as an "essential beginning". It was unclear whether all 192 countries in attendance would also adopt the deal. The Copenhagen Accord recognises the scientific case for keeping temperature rises below 2°C, but does not contain commitments for reduced emissions that would be necessary to achieve that aim. One part of the agreement pledges US$ 30 billion to the developing world over the next three years, rising to US$ 100 billion per year by 2020, to help poor countries adapt to climate change. Earlier proposals, that would have aimed to limit temperature rises to 1.5°C and cut CO 2 emissions by 80% by 2050 were dropped. An agreement was also reached that would set up a deal to reduce deforestation in return for cash from developed countries. The agreement made was non-binding but U.S. President Obama said that countries could show the world their achievements. He said that if they had waited for a binding agreement, no progress would have been made.

Analysis and aftermath Despite widely held expectations that the Copenhagen summit would produce a legally binding treaty, the conference was plagued by negotiating deadlock and the "Copenhagen Accord" is not legally enforceable. BBC environment analyst Roger Harrabin attributed the failure of the summit to live up to expectations to a number of factors including the recent global recession, and conservative domestic pressure in the US and China.

The editorial of The Australian newspaper on December 21, 2009, blamed African countries for turning Copenhagen into "a platform for demands that the world improve the continent's standard of living" and claimed that "Copenhagen was about oldfashioned anti-Americanism, not the environment".

British Prime Minister Gordon Brown accused a small number of nations of holding the Copenhagen talks to ransom.

The Copenhagen Accord asks countries to submit emissions targets by the end of January 2010, and paves the way for further discussions to occur at the 2010 UN 68

climate change conference in Mexico and the mid-year session in Bonn. However, some commentators consider that "the future of the UN's role in international climate deals is now in doubt."

CHAPTER 4 SEA LEVEL RISE INTRODUCTION

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Most of the world’s coastal cities were established during the last few millennia, a period when global sea level has been near constant. Since the mid-19th century, sea level has been rising, likely primarily as a result of human-induced climate change. During the 20th century, sea level rose about 15-20 centimeters (roughly 1.5 to 2.0 mm/year), with the rate at the end of the century greater than over the early part of the century. Satellite measurements taken over the past decade, however, indicate that the rate of increase has jumped to about 3.1 mm/year, which is significantly higher than the average rate for the 20th century . Projections suggest that the rate of sea level rise is likely to increase during the 21st century, although there is considerable controversy about the likely size of the increase. As explained in the next section, this controversy arises mainly due to uncertainties about the contributions to expect from the three main processes responsible for sea level rise: thermal expansion, the melting of glaciers and ice caps, and the loss of ice from the Greenland and West Antarctic ice sheets .

Causes of sea level rise Before describing the major factors contributing to climate change, it should be understood that the melting back of sea ice (e.g., in the Arctic and the floating ice shelves) will not directly contribute to sea level rise because this ice is already floating on the ocean (and so already displacing its mass of water). However, the 70

melting back of this ice can lead to indirect contributions on sea level. For example, the melting back of sea ice leads to a reduction in albedo (surface reflectivity) and allows for greater absorption of solar radiation. More solar radiation being absorbed will accelerate warming, thus increasing the melting back of snow and ice on land. In addition, ongoing break up of the floating ice shelves will allow a faster flow of ice on land into the oceans, thereby providing an additional contribution to sea level rise.

There are three major processes by which human-induced climate change directly affects sea level. First, like air and other fluids, water expands as its temperature increases (i.e., its density goes down as temperature rises). As climate change increases ocean temperatures, initially at the surface and over centuries at depth, the water will expand, contributing to sea level rise due to thermal expansion. Thermal expansion is likely to have contributed to about 2.5 cm of sea level rise during the second half of the 20th century, with the rate of rise due to this term having increased to about 3 times this rate during the early 21st century. Because this contribution to sea level rise depends mainly on the temperature of the ocean, projecting the increase in ocean temperatures provides an estimate of future growth. Over the 21st century, the IPCC’s Fourth Assessment projected that thermal expansion will lead to sea level rise of about 17-28 cm (plus or minus about 50%). That this estimate is less than would occur from a linear extrapolation of the rate during the first decade of the 21st century when all model projections indicate ongoing ocean warming has led to concerns that the IPCC estimate may be too low.

A second, and less certain, contributor to sea level rise is the melting of glaciers and ice caps. IPCC’s Fourth Assessment estimated that, during the second half of the 20th century, melting of mountain glaciers and ice caps led to about a 2.5 cm rise in sea level. This is a higher amount than was caused by the loss of ice from the Greenland and Antarctic ice sheets, which added about 1 cm to the sea level. For the 21st century, IPCC’s Fourth Assessment projected that melting of glaciers and ice caps will contribute roughly 10-12 cm to sea level rise, with an uncertainty of roughly

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a third. This would represent a melting of roughly a quarter of the total amount of ice tied up in mountain glaciers and small ice caps.

The third process that can cause sea level to rise is the loss of ice mass from Greenland and Antarctica. Were all the ice on Greenland to melt, a process that would likely take many centuries to millennia, sea level would go up by roughly 7 meters. The West Antarctic ice sheet holds about 5 m of sea level equivalent and is particularly vulnerable as much of it is grounded below sea level; the East Antarctic ice sheet, which is less vulnerable, holds about 55 m of sea level equivalent. The models used to estimate potential changes in ice mass are, so far, only capable of estimating

the

changes

in

mass

due

to

surface

processes

leading

to

evaporation/sublimation and snowfall and conversion to ice. In summarizing the results of model simulations for the 21st century, IPCC reported that the central estimates projected that Greenland would induce about a 2 cm rise in sea level whereas Antarctica would, because of increased snow accumulation, induce about a 2 cm fall in sea level. That there are likely to be problems with these estimates, however, has become clear with recent satellite observations, which indicate that both Greenland and Antarctica are currently losing ice mass, and we are only in the first decade of a century that is projected to become much warmer over its course.

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Overview of sea-level change Local mean sea level (LMSL) is defined as the height of the sea with respect to a land benchmark, averaged over a period of time (such as a month or a year) long enough that fluctuations caused by waves and tidesare smoothed out. One must adjust perceived changes in LMSL to account for vertical movements of the land, which can be of the same order (mm/yr) as sea level changes. Some land movements occur because of isostatic adjustment of the mantle to the melting of ice sheets at the end of the last ice age. The weight of the ice sheet depresses the underlying land, and when the ice melts away the land slowly rebounds. Atmospheric pressure, ocean currents and local ocean temperature changes also can affect LMSL. “Eustatic” change (as opposed to local change) results in an alteration to the global sea levels, such as changes in the volume of water in the world oceans or changes in the volume of an ocean basin.

Short term and periodic changes There are many factors which can produce short-term (a few minutes to 18.6 year ) changes in sea level.

Longer term changes Various factors affect the volume or mass of the ocean, leading to long-term changes in eustatic sea level. The two primary influences are temperature (because the volume of water depends on temperature), and the mass of water locked up on land and sea as fresh water in rivers, lakes, glaciers, polar ice caps, and sea ice. Over much longer geological timescales, changes in the shape of the oceanic basins and in land/sea distribution will affect sea level.

OCEANS & SEA LEVEL RISE

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Glaciers and ice caps Each year about 8 mm (0.3 inch) of water from the entire surface of the oceans falls into the Antarctica and Greenland ice sheets as snowfall. If no ice returned to the oceans, sea level would drop 8 mm every year. To a first approximation, the same amount of water appeared to return to the ocean in icebergs and from ice melting at the edges.

Scientists previously had estimated which is greater, ice going in or coming out, called the mass balance, important because it causes changes in global sea level. Highprecision gravimetry from satellites in low-noise flight has since determined Greenland is losing millions of tons per year, in accordance with loss estimates from ground measurement. Some estimates range up to 240 km^3 per year in recent years.

Ice shelves float on the surface of the sea and, if they melt, to first order they do not change sea level. Likewise, the melting of the northern polar ice cap which is composed of floating pack ice would not significantly contribute to rising sea levels. Because they 74

are fresh, however, their melting would cause a very small increase in sea levels, so small that it is generally neglected. It can however be argued that if ice shelves melt it is a precursor to the melting of ice sheets on Greenland and Antarctica. 

If

small glaciers and polar ice

caps on

the

margins of

Greenland

and

the Antarctic Peninsula melt, the projected rise in sea level will be around 0.5 m. Melting of the Greenland ice sheet would produce 7.2 m of sea-level rise, and melting of the Antarctic ice sheet would produce 61.1 m of sea level rise. The collapse of the grounded interior reservoir of the West Antarctic Ice Sheet would raise sea level by 5-6 m. 

The interior of the Greenland and Antarctic ice sheets is sufficiently high (and

therefore cold) enough that direct melt there cannot cause them to melt in a time-frame less than several millennia; therefore it is likely that they will not, through melting of the interior, contribute significantly to sea level rise in the coming century. They can, however, do so through acceleration in flow and enhanced iceberg calving. Also, melt of the fringes of the ice caps could be significant, as could be sub-ice-shelf melting in Antarctica. 

Climate changes during the 20th century are estimated from modelling studies to

have led to contributions of between –0.2 and 0.0 mm/yr from Antarctica (the results of increasing precipitation) and 0.0 to 0.1 mm/yr from Greenland (from changes in both precipitation and runoff). 

Estimates suggest that Greenland and Antarctica have contributed 0.0 to

0.5 mm/yr over the 20th century as a result of long-term adjustment to the end of the last ice age.

Since 1992 a number of satellites have been recording the change in sea level; they display an acceleration in the rate of sea level change, but they have not been operating for long enough to work out whether this is a real signal, or just an artefact of short-term variation.

75

Past changes in sea level

Changes in sea level during the last 9,000 years The sedimentary record For generations, geologists have been trying to explain the obvious cyclicity of sedimentary deposits observed everywhere we look. The prevailing theories hold that this cyclicity primarily represents the response of depositional processes to the rise and fall of sea level. In the rock record, geologists see times when sea level was astoundingly low alternating with times when sea level was much higher than today, and these anomalies often appear worldwide. For instance, during the depths of the last ice age 18,000 years ago when hundreds of thousands of cubic miles of ice were stacked up on the continents as glaciers, sea level was 120 m (390 ft) lower, locations that today support coral reefs were left high and dry, and coastlines were miles farther basinward from the present-day coastline. It was during this time of very low sea level that there was a dry land connection between Asia and Alaska over which humans are believed to have migrated to North America .However, for the past 6,000 years (a few centuries before the first known written records), the world's sea level has been gradually approaching the level we see today. During the previous interglacial about 120,000 years ago, sea level was for a short time about 6 m higher than today, as evidenced by wave-cut notches along cliffs in the Bahamas. There are also Pleistocene coral reefs left stranded about 3 metres above today's sea level along the southwestern 76

coastline of West Caicos Island in the West Indies. These once-submerged reefs and nearby paleo-beach deposits are silent testimony that sea level spent enough time at that higher level to allow the reefs to grow (exactly where this extra sea water came from—Antarctica or Greenland—has not yet been determined). Similar evidence of geologically recent sea level positions is abundant around the world.

Glacier contribution It is well known that glaciers are subject to surges in their rate of movement with consequent melting when they reach lower altitudes and/or the sea. The contributors to Annals of Glaciology. Historical reports of surge occurrences in Iceland's glaciers go back several centuries. Thus rapid retreat can have several other causes than CO2 increase in the atmosphere.

Greenland contribution Krabill estimate a net contribution from Greenland to be at least 0.13 mm/yr in the 1990s. Joughin have measured a doubling of the speed of Jakobshavn Isbræ between 1997 and 2003. This is Greenland's largest-outlet glacier; it drains 6.5% of the ice sheet, and is thought to be responsible for increasing the rate of sea level rise by about 0.06 millimetres per year, or roughly 4% of the 20th century rate of sea level increase.

In 2004, Rignot et al. estimated a contribution of 0.04±0.01 mm/yr to sea level rise from southeast Greenland.

Rignot and Kanagaratnam] produced a comprehensive study and map of the outlet glaciers and basins of Greenland. They found widespread glacial acceleration below 66 N in 1996 which spread to 70 N by 2005; and that the ice sheet loss rate in that decade increased from 90 to 200 cubic km/yr; this corresponds to an extra 0.25 to 0.55 mm/yr of sea level rise.

In July 2005 it was reported that the Kangerdlugssuaq glacier, on Greenland's east coast, was moving towards the sea three times faster than a decade earlier.

Kangerdlugssuaq is around 1,000 m thick, 7.2 km (4.5 miles) wide, and drains about 4% of the ice from the Greenland ice sheet. Measurements of Kangerdlugssuaq in 1988

77

and 1996 showed it moving at between 5 and 6 km/yr (3.1 to 3.7 miles/yr) (in 2005 it was moving at 14 km/yr [8.7 miles/yr]).

Arctic contribution According to the 2004 Arctic Climate Impact Assessment, climate models project that local warming in Greenland will exceed 3° Celsius during this century. Also, ice sheet models project that such a warming would initiate the long-term melting of the ice sheet, leading to a complete melting of the Greenland ice sheet over several millennia, resulting in a global sea level rise of about seven metres.

Antarctic contribution On the Antarctic continent itself, the large volume of ice present stores around 70 % of the world's fresh water. This ice sheet is constantly gaining ice from snowfall and losing ice through outflow to the sea. West Antarctica is currently experiencing a net outflow of glacial ice, which will increase global sea level over time. A review of the scientific studies looking at data from 1992 to 2006 suggested a net loss of around 50Gigatonnes of ice per year was a reasonable estimate (around 0.14 mm of sea level rise), although significant acceleration of outflow glaciers in the Amundsen Sea Embayment could have more than doubled this figure for the year 2006.

East Antarctica is a cold region with a ground base above sea level and occupies most of the continent. This area is dominated by small accumulations of snowfall which becomes ice and thus eventually seaward glacial flows. The mass balance of the East Antarctic Ice Sheet as a whole is thought to be slightly positive (lowering sea level) or near to balance. However, increased ice outflow has been suggested in some regions.

Effects of snowline and permafrost The snowline altitude is the altitude of the lowest elevation interval in which minimum annual snow cover exceeds 50%. This ranges from about 5,500 metres above sea-level at the equator down to sea-level at about 65° N&S latitude, depending on regional temperature amelioration effects. Permafrost then appears at sea-level and extends deeper below sea-level pole-wards. The depth of permafrost and the height of the icefields in both Greenland and Antarctica means that they are largely invulnerable to rapid 78

melting. Greenland Summit is at 3,200 metres, where the average annual temperature is minus 32 °C. So even a projected 4 °C rise in temperature leaves it well below the melting point of ice. Frozen Ground 28, December 2004, has a very significant map of permafrost affected areas in the Arctic.

Polar ice The sea level will rise above its current level if more polar ice melts. However, compared to the heights of the ice ages, today there are very few continental ice sheets remaining to be melted. It is estimated that Antarctica, if fully melted, would contribute more than 60 metres of sea level rise, and Greenland would contribute more than 7 metres. Small glaciers and ice caps on the margins of Greenland and the Antarctic Peninsula might contribute about 0.5 metres. While the latter figure is much smaller than for Antarctica or Greenland it could occur relatively quickly (within the coming century) whereas melting of Greenland would be slow (perhaps 1,500 years to fully deglaciate at the fastest likely rate) and Antarctica even slower. However, this calculation does not account for the possibility that as meltwater flows under and lubricates the larger ice sheets, they could begin to move much more rapidly towards the sea.

Consequences of Climate Change on the Oceans •

Melting of Glaciers and Ice Sheets

•

Sea Level Rise

•

Ocean Acidification

•

Thermohaline Circulation

Melting of Glaciers and Ice Sheets One of the most pronounced effects of climate change has been melting of masses of ice around the world. Glaciers and ice sheets are large, slow-moving assemblages of ice that cover about 10% of the world’s land area and exist on every continent

79

except Australia. They are the world’s largest reservoir of fresh water, holding approximately 75%.

Over the past century, most of the world’s mountain glaciers and the ice sheets in both Greenland and Antarctica have lost mass. Retreat of this ice occurs when the mass balance (the difference between accumulation of ice in the winter versus ablation or melting in the summer) is negative such that more ice melts each year than is replaced. By affecting the temperature and precipitation of a particular area, both of which are key factors in the ability of a glacier to replenish its volume of ice, climate change affects the mass balance of glaciers and ice sheets. When the temperature exceeds a particular level or warm temperatures last for a long enough period, and/or there is insufficient precipitation, glaciers and ice sheets will lose mass.

When researching glacial melting, scientists must consider not only how much ice is being lost, but also how quickly. Recent studies show that the movement of ice towards the ocean from both of the major ice sheets has increased significantly. As the speed increases, the ice streams flow more rapidly into the ocean, too quickly to 80

be replenished by snowfall near their heads. The speed of movement of some of the ice streams draining the Greenland Ice Sheet, for example, has doubled in just a few years . Using various methods to estimate how much ice is being lost (such as creating a ‘before and after’ image of the ice sheet to estimate the change in shape and therefore volume, or using satellites to ‘weigh’ the ice sheet by computing its gravitational pull), scientists have discovered that the mass balance of the Greenland Ice Sheet has become negative in the past few years. Estimates put the net loss of ice at anywhere between 82 and 224 cubic kilometers per year .

Image from UNEP In Antarctica, recent estimates show a sharp contrast between what is occurring in the East and West Antarctic Ice Sheets. The acceleration of ice loss from the West Antarctic Ice Sheet has doubled in recent years, which is similar to what has happened in Greenland. In West Antarctica, as well as in Greenland, the main reason for this increase is the quickening pace at which glacial streams are flowing into the ocean. Scientists estimate the loss of ice from the West Antarctic ice sheet to be from 47 to 148 cubic kilometers per year. On the other hand, recent measurements indicate that the East Antarctic ice sheet (which is much larger than 81

the West) is gaining mass because of increased precipitation. However, it must be noted that this gain in mass by the East Antarctic ice sheet is nowhere near equal to the loss from the West Antarctic ice sheet . Therefore, the mass balance of the entire Antarctic Ice Sheet is negative.

Effects of sea level rise Current and future climate change would be expected to have a number of impacts, particularly on coastal systems. Such impacts may include increased coastal erosion, higher storm-surge flooding, inhibition of primary production processes, more extensive coastal inundation, changes in surface water quality and groundwater characteristics, increased loss of property and coastal habitats, increased flood risk and potential loss of life,

loss

of

non

monetary cultural

resources

&

values,

impacts

on agriculture and aquaculture through decline in soil and water quality, and loss of tourism, recreation, and transportation functions.

There is an implication that many of these impacts will be detrimental—especially for the three-quarters of the world's poor who depend on agriculture systems. The report does, however, note that owing to the great diversity of coastal environments; regional and local differences in projected relative sea level and climate changes; and differences in the resilience and adaptive capacity of ecosystems, sectors, and countries, the impacts will be highly variable in time and space.

The melting back of the glaciers and ice sheets has two major impacts. First, areas that rely on the runoff from the melting of mountain glaciers are very likely to experience severe water shortages as the glaciers disappear. Less runoff will lead to a reduced capability to irrigate crops as freshwater dams and reservoirs more frequently go dry. Water shortages could be especially severe in parts of South America and Central Asia, where summertime runoff from the Andes and the Himalayas, respectively, is crucial for fresh water supplies . Also, in areas of North America and Europe, glacial runoff is used to power hydroelectric plants, sustain fish runs and irrigate crops as well as to supply the needs of large metropolitan areas. As the volume of runoff decreases, then the energy, urban, and agricultural infrastructures of such locations are likely to be stressed .

82

While there are obviously many challenges to projecting future sea level rise, even a seemingly small increase in sea level can have a dramatic impact on many coastal environments. Over 600 million people live in coastal areas that are less than 10 meters above sea level, and two-thirds of the world’s cities that have populations over five million are located in these at-risk areas . With sea level projected to rise at an accelerated rate for at least several centuries, very large numbers of people in vulnerable locations are going to be forced to relocate. If relocation is delayed or populations do not evacuate during times when the areas are inundated by storm surges, very large numbers of environmental refugees are likely to result.

According to the IPCC, even the best-case scenarios indicate that a rising sea level would have a wide range of impacts on coastal environments and infrastructure.

Effects are likely to include coastal erosion, wetland and coastal plain flooding, salinization of aquifers and soils, and a loss of habitats for fish, birds, and other wildlife and plants . The Environmental Protection Agency estimates that 26,000 square kilometers of land would be lost should sea level rise by 0.66 meters, while the IPCC notes that as much as 33% of coastal land and wetland habitats are likely to be lost in the next hundred years if the level of the ocean continues to rise at its present rate. Even more land would be lost if the increase is significantly greater, and this is quite possible . As a result, very large numbers of wetland and swamp species are likely at serious risk. In addition, species that rely upon the existence of sea ice to survive are likely to be especially impacted as the retreat accelerates, posing the threat of extinction for polar bears, seals, and some breeds of penguins.

Unfortunately, many of the nations that are most vulnerable to sea level rise do not have the resources to prepare for it. Low-lying coastal regions in developing countries such as Bangladesh, Vietnam, India, and China have especially large populations living in at-risk coastal areas such as deltas, where river systems enter the ocean. Both large island nations such as the Philippines and Indonesia and small ones such as Tuvalu and Vanuatu are at severe risk because they do not have enough land at higher elevations to support displaced coastal populations. Another possibility for some island nations is the danger of losing their fresh-water supplies as 83

sea level rise pushes saltwater into their aquifers. For these reasons, those living on several small island nations (including the Maldives in the Indian Ocean and the Marshall Islands in the Pacific) could be forced to evacuate over the 21st century.

Ocean Acidification Each year the oceans absorb the equivalent of about a third of human emissions of carbon dioxide (CO2), transferring most of it to the deep ocean . Over the past 200 years, the increasing CO2 emissions from fossil fuel combustion have led to an exponential increase in the net amount of CO2 being dissolved in the ocean.

Dissolved CO2 creates carbonic acid, which reduces the ocean pH level, making it more acidic .

Acidity is measured using the pH scale, where items are given a numerical value between 0 and 14. A value of seven is neutral, with higher values being described as basic and lowers values as acidic. Historically, ocean pH has averaged around 8.17, meaning that ocean waters are slightly basic. But with the rising CO2 concentration causing acidification, today the pH levels are around 8.09, edging the waters closer to neutral . Geological evidence and model reconstructions indicate that, over the past 300 million years, the average pH of the ocean has not varied by more than 0.6 from its present value. Thus, the marine ecosystems present today have evolved in a relatively stable pH environment. With the rising CO2 concentration over the last 200 years, ocean pH has been steadily decreasing. While the acidification of the oceans is not yet itself worrisome except in polar regions, the rate at which the pH is dropping is becoming alarming. This is because the rate of change is so much higher than the natural weathering processes that have, in the past, buffered changes in ocean pH. If the CO2 concentration continues to rise and the pH level continues to fall at current rates, the ocean pH could drop by as much as 0.5 during the 22nd century. Such a drastic change would very likely have a substantial adverse impact on ocean life.

84

Island nations IPCC assessments suggest that deltas and small island states are particularly vulnerable to sea level rise caused by both thermal expansion and ocean volume.

Relative sea level rise (mostly caused by subsidence) is currently causing substantial loss of lands in some deltas. Sea level changes have not yet been conclusively proven to have directly resulted in environmental, humanitarian, or economic losses to small island states, but the IPCC and other bodies have found this a serious risk scenario in coming decades.

Many media reports have focused the island nations of the Pacific, notably the Polynesian islands of Tuvalu, which based on more severe flooding events in recent years, was thought to be "sinking" due to sea level rise. A scientific review in 2000 reported that based onUniversity of Hawaii gauge data, Tuvalu had experienced a negligible increase in sea-level of 0.07 mm a year over the past two decades, and that ENSO had been a larger factor in Tuvalu's higher tides in recent years. A subsequent study by John Hunter from the University of Tasmania, however, adjusted for ENSO effects and the movement of the gauge (which was thought to be sinking).

Hunter concluded that Tuvalu had been experiencing sea-level rise of about 1.2 mm per year. The recent more frequent flooding in Tuvalu may also be due to anerosional loss of land during and following the actions of 1997 cyclones Gavin, Hina, and Keli.

Numerous options have been proposed that would assist island nations to adapt to rising sea level.

Possible impacts/ Preventative Measures The most direct impacts of ocean acidification will be on marine ecosystems. A decrease in ocean pH would affect marine life by lowering the amount of calcium carbonate (the substance created when CO2 is initially dissolved) in the water.

Calcium carbonate is the substance used by many marine organisms (including coral, shellfish, crustaceans, and mollusks) to build their shells . If the pH drops by the expected 0.5 during this century, the resulting effect would be a 60% drop in available calcium carbonate. Such a decrease would put the productivity and even the survival of thousands of marine species at risk.

85

To prevent the rapid acidification of the ocean and hold the pH level within an acceptable range for marine life, the atmospheric CO2 concentration needs to be kept below no more than about 450 parts per million (ppm). With the current concentration at roughly 387 ppm, the concentration seems likely to be near 500 ppm by mid-century without sharp reductions in emissions. To keep the decrease in pH to less than 0.2 pH, which could help to protect critical marine ecosystems, will require keeping the CO2concentration below about 450 ppm .

Thermohaline Circulation Another impact of glacial retreat is the possible effect fresh melt water will have on the thermohaline circulation. Driven by density gradients in ocean waters, the thermohaline (or deep ocean overturning) circulation is made up of the global flow of ocean currents. As ocean waters move around, different water masses are formed as evaporation removes fresh water and precipitation and river runoff add fresh water, each changing ocean salinity and therefore the density of the waters. Surface currents, which are largely driven by wind patterns, take the water masses to areas where they are warmed by high solar radiation (leading to lower density) or cooled in higher latitudes (leading to higher density). When surface water density becomes greater than for waters below, downwelling currents carry the denser surface waters down and push less dense, nutrient rich waters toward the surface, where winds bring them all the way to the surface and create areas rich with marine life. Thus, the density gradients created by temperature (cold water is more dense than water that is warm) and salinity (salt water is more dense than freshwater) are critical to both how ocean waters move and where there are nutrients that promote significant marine life. Because both temperature and salinity are influenced by changes in the climate, there are concerns about the ways in which the thermohaline circulation might be affected.

The influences can operate in various ways. First, ocean circulation could be influenced by changes in runoff from glaciers and ice sheets. As glaciers melt and release fresh water into the ocean, the influx dilutes saltier waters, likely reducing the 86

rate of bottom water formation because relatively fresh water will not be able to sink (even at higher latitudes where it becomes cold and dense), thus affecting deep ocean currents. With the rate at which glaciers are melting and the amount of freshwater that might be introduced into the ocean changing, it is thus quite possible that the intensity of the thermohaline circulation could be reduced.

Climate change will not only affect salinity levels, but will also affect ocean temperatures and circulation patterns. First, as ocean temperatures increase, thermal expansion will cause the density to decrease and so increase the volume of ocean waters, raising sea level. Because surface currents are driven by the winds, warm surface waters moved by the winds are generally replaced by the colder waters underneath, with the upwelling bringing up nutrient-rich colder waters that promote flourishing marine life. As ocean surface waters warm and become less likely to sink, a smaller amount of cold water is brought up to the surface, impacting circulation patterns and marine life. In addition, warmer temperatures will lead to more evaporation. When the water evaporates, the salt stays behind. An increase in salinity changes the density of the water, and therefore affects circulations patterns.

Given the interactions of these processes, there are increasing concerns that climate change will reduce the overall intensity of the thermohaline (deep-ocean) circulation.

Changes such as these could be quite important for northern European countries.

The Gulf Stream carries warm water from the tropics to the North Atlantic, and the heat it gives off to the atmosphere contributes to the mild temperatures in the region, 87

even though Europe is located at a relatively high latitude. With sufficient cooling, the water sinks near Greenland and further north, pulling more warm waters northward from the tropics. If ocean warming slows the thermohaline circulation, less warm water would be transported north and Europe would likely experience less warming or even a cooling .

Such a cooling event may have occurred during the Younger Dryas about 12,000 years ago when meltwater release from rapid deglaciation of North America freshened the North Atlantic, likely shutting off the deep ocean circulation and disrupting weather and ocean circulation patterns . Within a decade of the shutdown of the thermohaline circulation, global climate patterns were altered significantly and European and North American temperatures dropped by as much as 15ºC. Such a rapid and dramatic shift in climate has not happened since, but with melting of Greenland beginning, there is an increasing risk of a similarly sudden shift in the future .

4 less expected consequences of rising sea levels due to global warming Salinity itself will effect our water supply - We all know that global warming will cause sea levels to rise. Therefore, most of us understand that places which right now are above water could end up underwater. Further, the masses tend to understand that the added heat could serve to dry up reservoirs.

However, very little has been discussed concerning salinity (in other words, salt). Simply put, if the ocean rises it will increase the salinities of estuaries (the lower course of a river where its currents are met by tides) and aquifers (underground beds or layers of earth, gravel, or porous stone that yield water). When this happens, the extra salt will impair water supplies and reservoirs as nearly all coastal water supplies are significantly impacted by the ocean to begin with.

Said another way, New York, Philadelphia, and California get a lot of their water from upstream rivers. If salt were to venture further upstream it would in essence destroy 88

much of their water supplies. Not to mention that salinity increases in such waters when the heat is high.

How to survive rising sea levels due to global warming First thing we must all do is understand that some of these changes will take place no matter what we do (whether emissions are lessened or not). Thus, we must all understand that adaptation is a must. Once that is understood, then change can take place.

So, here are three ideas on how to combat these sea level issues through adaptation.

1. Make a wall - Coastal cities and areas will need protection. One obvious way to attempt this is through walling them off with bulkheads, dikes, seawalls, and pumping systems. Dikes and pumping systems are already being used in areas such as New Orleans that are well below sea level. In fact, all of these are being used effectively in other parts of the country..

Though these manmade structures will help save property and stop flooding, they may not serve to protect shorelines aesthetically; nor will they necessarily protect ecosystems (marshes, etc.) from harm.

2. Elevate the land - Using fill to elevate beaches/ the area around bodies of water has been successful in other parts of the country. The nice thing about this method of dealing with rising sea levels is that it will allow beaches to keep much of their aesthetic beauty and recreational usefulness.

This method will be an especially prudent one to use in areas where the shoreline is important to the economy, as is the case with the Caribbean islands, Hawaii, and the like. But again, remember that even if the beaches stay intact, the surfing could be rough due to the increased size of waves. So practice with caution all of you surfer dudes!

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3. Learn how to effectively turn saltwater into drinking water - Okay, this is the one that could solve the problem of negatively impacted reservoirs and lessened rain due in part to rising sea levels. First, it is important to understand that desalination (the process of taking the salt out of ocean water, usually for the purpose of drinking it) is something that we can already do. For instance, desalination has been occurring on ships and other arid regions of the world for some time now. However, it is time consuming and expensive (it costs about $1,000 per acre foot to desalinate ocean water as opposed to $200 per acre foot to utilize normal drinking water). Still, the prices are falling. Further, there may be a time when we have no choice but to go to the ocean for our drinking water. Then - as with everything else our ability to do this in a cost effective manner will no doubt increase when/ if this time comes.

In sum, rising sea levels will cause more problems than just flooding. One particularly troubling aspect of sea level increases is the amount of salt that will be let loose on our world. However, there are things that can be done about all of this. But before we can be effective in dealing with sea level increases, we must admit to ourselves as a society that global warming is a permanent problem (that can only be mitigated by lessening emissions, not solved entirely). Only then will we begin to turn our focus toward adaptation.

Conclusion As CO2 emissions and climate change continue, risks to the health of the ocean will become a more prominent concern. With accelerated melting back of glaciers and ice sheets and the subsequent rise in sea level, with further decreases in oceanic pH, and with deceleration of the thermohaline circulation, there are many ways in which the delicate balance of ocean dynamics and ecosystems are being put at risk. These factors, combined with the uncertainty in predicting exactly how these impacts will interact, are causing changes in the ocean: an increasingly problematic issue for future generations.

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CHAPTER 5 GLOBAL WARMING

INTRODUCTION Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) between the start and the end of the 20th century. The Intergovernmental Panel on Climate Change (IPCC) concludes that most of the observed temperature increase since the middle of the 20th century was caused by increasing concentrations of greenhouse gases resulting from human activity such as fossil fuel burning and deforestation. The IPCC also concludes that variations in natural phenomena such as solar radiation and volcanismproduced most of the warming from pre-industrial times to 1950 and had a small cooling effect afterward. These basic conclusions have been endorsed by more than 40 scientific 91

societies and academies of science, including all of the national academies of science of the major industrialized countries.

Climate model projections summarized in the latest IPCC report indicate that the global surface temperature will probably rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century. ]The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates

of

future

greenhouse

gas

emissions.

Some

other uncertainties include how warming and related changes will vary from region to region around the globe. Most studies focus on the period up to the year 2100.

However, warming is expected to continue beyond 2100 even if emissions stop, because of the large heat capacity of the oceans and the long lifetime of carbon dioxide in the atmosphere.

An increase in global temperature will cause sea levels to rise and will change the amount

and

pattern

of precipitation,

probably

including

expansion

of subtropical deserts. The continuing retreat of glaciers, permafrost and sea ice is expected, with warming being strongest in the Arctic. Other likely effects include increases in the intensity of extreme weather events, species extinctions, and changes in agricultural yields.

Political and public debate continues regarding global warming, and what actions (if any) to take in response. The available options are mitigation to reduce further emissions; adaptation to reduce the damage caused by warming; and, more speculatively, geoengineering to

reverse

global

warming.

Most

national

governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions.

Temperature changes Temperature record

92

Two millennia of mean surface temperatures according to different reconstructions, each smoothed on a decadal scale. The unsmoothed, annual value for 2004 is also plotted for reference.

The most commonly discussed measure of global warming is the trend in globally averaged temperature near the Earth's surface. Expressed as a linear trend, this temperature rose by 0.74°C ±0.18°C over the period 1906–2005. The rate of warming over the last half of that period was almost double that for the period as a whole (0.13°C ±0.03°C per decade, versus 0.07°C ± 0.02°C per decade). The urban heat island effect is estimated to account for about 0.002 °C of warming per decade since 1900.

Temperatures in the lower troposphere have increased between 0.12 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to satellite temperature measurements.

Temperature is believed to have been relatively stable over the one or two thousand years before 1850, with regionally-varying fluctuations such as the Medieval Warm Periodor the Little Ice Age. Based on estimates by NASA's Goddard Institute for Space Studies, 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree.] Estimates prepared by the World Meteorological Organization and the Climatic Research Unit concluded that 2005 was the second warmest year, behind 1998. Temperatures in 1998 were unusually warm because the strongest El Niño in the 93

past century occurred during that year. Global temperature is subject to short-term fluctuations that overlay long term trends and can temporarily mask them. The relative stability in temperature from 1999 to 2009 is consistent with such an episode.

Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 °C per decade against 0.13 °C per decade). Ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation.] The Northern Hemisphere warms faster than the Southern Hemisphere because it has more land and because it has extensive areas of seasonal snow and sea-ice cover subject to ice-albedo feedback. Although more greenhouse gases are emitted in the Northern than Southern Hemisphere this does not contribute to the difference in warming because the major greenhouse gases persist long enough to mix between hemispheres. The thermal inertia of the oceans and slow responses of other indirect effects mean that climate can take centuries or longer to adjust to changes in forcing. Climate commitment studies indicate that even if greenhouse

gases

were

stabilized

at

2000

levels,

a

further

warming

of

about 0.5 °C (0.9 °F) would still occur.

Radiative forcing External forcing is a term used in climate science for processes external to the climate system (though not necessarily external to Earth). Climate responds to several types of external forcing, such as changes in greenhouse gas concentrations, changes in solar luminosity, volcaniceruptions, and variations in Earth's orbit around the Sun. Attribution of recent climate change focuses on the first three types of forcing. Orbital cycles vary slowly over tens of thousands of years and thus are too gradual to have caused the temperature changes observed in the past century.

94

Greenhouse gases

Greenhouse effect schematic showing energy flows between space, the atmosphere, and earth's surface. Energy exchanges are expressed in watts per square meter (W/m2).

Recent atmospheric carbon dioxide(CO2) increases. Monthly CO2measurements display seasonal oscillations in overall yearly uptrend; each year's maximum occurs during the Northern Hemisphere's late spring, and declines during its growing season as plants remove some atmospheric CO2.

The

greenhouse

effect

is

the

process

by

which absorption and emission of infrared radiation by gases in the atmosphere warm 95

a planet's lower atmosphere and surface. It was discovered by Joseph Fourier in 1824 and was first investigated quantitatively. Existence of the greenhouse effect as such is not disputed, even by those who do not agree that the recent temperature increase is attributable to human activity. The question is instead how the strength of the greenhouse effect changes when human activity increases the concentrations of greenhouse gases in the atmosphere.

Naturally occurring greenhouse gases have a mean warming effect of about 33 °C (59 °F). The major greenhouse gases are water vapor, which causes about 36–70 percent of the greenhouse effect; carbon dioxide (CO2), which causes 9–26 percent; methane (CH4), which causes 4–9 percent; and ozone (O3), which causes 3–7 percent. Clouds also affect the radiation balance, but they are composed of liquid water or ice and so are considered separately from water vapor and other gases.

Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs and nitrous oxide. The concentrations of CO2 and methane have increased by 36% and 148% respectively since the mid-1700s. These levels are much higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from ice cores. Less direct geological evidence indicates that CO2 values this high were last seen about 20 million years ago. Fossil fuel burning has produced about three-quarters of the increase in CO 2 from human activity over the past 20 years. Most of the rest is due to land-use change, particularly deforestation.

CO2 concentrations are continuing to rise due to burning of fossil fuels and land-use change.

The

future

rate

of

rise

will

depend

on

uncertain

economic, sociological, technological, and natural developments. Accordingly, the IPCC Special Report on Emissions Scenarios gives a wide range of future CO2scenarios, ranging from 541 to 970 ppm by the year 2100. Fossil fuel reserves are sufficient to reach these levels and continue emissions past 2100 if coal, tar sands or methane

clathrates are

extensively

exploited.

The

destruction

of stratospheric ozone by chlorofluorocarbons is sometimes mentioned in relation to global warming. Although there are a few areas of linkage, the relationship between the 96

two is not strong. Reduction of stratospheric ozone has a cooling influence, but substantial ozone depletion did not occur until the late 1970s. Tropospheric ozone contributes to surface warming.

Global dimming, a gradual reduction in the amount of global direct irradiance at the Earth's surface, has partially counteracted global warming from 1960 to the present. The main cause of this dimming isaerosols produced by volcanoes and pollutants. These aerosols exert a cooling effect by increasing the reflection of incoming sunlight. James Hansen and colleagues have proposed that the effects of the products of fossil fuel combustion—CO 2 and aerosols—have largely offset one another in recent decades, so that net warming has been driven mainly by non-CO 2 greenhouse gases. In addition to their direct effect by scattering and absorbing solar radiation, aerosols have indirect effects on the radiation budget. Sulfate aerosols act as cloud condensation nuclei and thus lead to clouds that have more and smaller cloud droplets.

These clouds reflect solar radiation more efficiently than clouds with fewer and larger droplets. This effect also causes droplets to be of more uniform size, which reducesgrowth of raindrops and makes the cloud more reflective to incoming sunlight.

Soot may cool or warm, depending on whether it is airborne or deposited.

Atmospheric soot aerosols directly absorb solar radiation, which heats the atmosphere and cools the surface. Regionally (but not globally), as much as 50% of surface warming due to greenhouse gases may be masked by atmospheric brown clouds.

When deposited, especially on glaciers or on ice in arctic regions, the lower surface albedo can also directly heat the surface. The influences of aerosols, including black carbon, are most pronounced in the tropics and sub-tropics, particularly in Asia, while the effects of greenhouse gases are dominant in the extratropics and southern hemisphere.

Solar variation

97

Solar variation over the last thirty years.

Variations in solar output have been the cause of past climate changes, but solar forcing is generally thought to be too small to account for a significant part of global warming in recent decades. However, a 2007 phenomenological analysis indicated that the contribution of solar forcing may be underestimated.

Greenhouse gases and solar forcing affect temperatures in different ways. While both increased solar activity and increased greenhouse gases are expected to warm the troposphere, an increase in solar activity should warm the stratosphere while an increase in greenhouse gases should cool the stratosphere. Observations show that temperatures in the stratosphere have been steady or cooling since 1979, when satellite measurements became available. Radiosonde (weather balloon) data from the presatellite era show cooling since 1958, though there is greater uncertainty in the early radiosonde record. A related hypothesis, proposed by Henrik Svensmark, is that magnetic activity of the sun deflects cosmic rays that may influence the generation of cloud condensation nuclei and thereby affect the climate. Other research has found no relation between warming in recent decades and cosmic rays A recent study concluded that the influence of cosmic rays on cloud cover is about a factor of 100 lower than needed to explain the observed changes in clouds or to be a significant contributor to present-day climate change.

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Feedback A positive feedback is a process that amplifies some change. Thus, when a warming trend results in effects that induce further warming, the result is a positive feedback; when the warming results in effects that reduce the original warming, the result is a negative feedback. The main positive feedback in global warming involves the tendency of warming to increase the amount of water vapor in the atmosphere. The main negative feedback in global warming is the effect of temperature on emission of infrared radiation: as the temperature of a body increases, the emitted radiation increases with the fourth power of its absolute temperature.

Water vapor feedback If the atmosphere is warmed, the saturation vapor pressure increases, and the amount of water vapor in the atmosphere will tend to increase. Since water vapor is a greenhouse gas, the increase in water vapor content makes the atmosphere warm further; this warming causes the atmosphere to hold still more water vapor (a positive feedback), and so on until other processes stop the feedback loop. The result is a much larger greenhouse effect than that due to CO 2 alone. Although this feedback process causes an increase in the absolute moisture content of the air, the relative humidity stays nearly constant or even decreases slightly because the air is warmer.

Cloud feedback Warming is expected to change the distribution and type of clouds. Seen from below, clouds emit infrared radiation back to the surface, and so exert a warming effect; seen from above, clouds reflect sunlight and emit infrared radiation to space, and so exert a cooling effect. Whether the net effect is warming or cooling depends on details such as the type and altitude of the cloud. These details were poorly observed before the advent of satellite data and are difficult to represent in climate models.

Lapse rate The atmosphere's temperature decreases with height in the troposphere. Since emission of infrared radiation varies with temperature,longwave radiation escaping to space from the relatively cold upper atmosphere is less than that emitted toward the 99

ground from the lower atmosphere. Thus, the strength of the greenhouse effect depends on the atmosphere's rate of temperature decrease with height. Both theory and climate models indicate that global warming will reduce the rate of temperature decrease with height, producing a negative lapse rate feedback that weakens the greenhouse effect. Measurements of the rate of temperature change with height are very sensitive to small errors in observations, making it difficult to establish whether the models agree with observations.

Ice-albedo feedback

Aerial photograph showing a section of sea ice. The lighter blue areas are melt ponds and the darkest areas are open water, both have a lower albedo than the white sea ice. The melting ice contributes to ice-albedo feedback.

When ice melts, land or open water takes its place. Both land and open water are on average less reflective than ice and thus absorb more solar radiation. This causes more warming, which in turn causes more melting, and this cycle continues.

Arctic methane release Warming is also the triggering variable for the release of methane in the arctic. Methane released from thawing permafrost such as the frozen peat bogs in Siberia, and from methane clathrate on the sea floor, creates a positive feedback.

Reduced absorption of CO2 by the oceanic ecosystems 100

Ocean ecosystems' ability to sequester carbon is expected to decline as the oceans warm. This is because warming reduces the nutrient levels of the mesopelagic zone (about 200 to 1000 m deep), which limits the growth of diatoms in favor of smaller phytoplankton that are poorer biological pumps of carbon.

CO2 release from oceans Cooler water can absorb more CO 2. As ocean temperatures rise some of this CO 2 will be released. This is one of the main reasons why atmospheric CO 2 is lower during an ice age. There is a greater mass of CO 2 contained in the oceans than there is in the atmosphere.

Gas release Release of gases of biological origin may be affected by global warming, but research into such effects is at an early stage. Some of these gases, such as nitrous oxide released

from peat,

directly

affect

climate.

Others,

such

as dimethyl

sulfide released from oceans, have indirect effects Climate models

Calculations of global warming prepared in or before 2001 from a range of climate models under the SRES A2 emissions scenario, which assumes no action is taken to reduce emissions and regionally divided economic development.

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The geographic distribution of surface warming during the 21 st century calculated by the HadCM3 climate model if a business as usual scenario is assumed for economic growth and greenhouse gas emissions. In this figure, the globally averaged warming corresponds to 3.0 °C (5.4 °F).

The main tools for projecting future climate changes are mathematical models based on physical principles including fluid dynamics, thermodynamics and radiative transfer.

Although they attempt to include as many processes as possible, simplifications of the actual climate system are inevitable because of the constraints of available computer power and limitations in knowledge of the climate system. All modern climate models are in fact combinations of models for different parts of the Earth. These include an atmospheric model for air movement, temperature, clouds, and other atmospheric properties; an ocean model that predicts temperature, salt content, and circulation of ocean waters; models for ice cover on land and sea; and a model of heat and moisture transfer from soil and vegetation to the atmosphere. Some models also include treatments of chemical and biological processes. Warming due to increasing levels of greenhouse gases is not an assumption of the models; rather, it is an end result from the interaction of greenhouse gases with radiative transfer and other physical processes in the models. Although much of the variation in model outcomes depends on the greenhouse gas emissions used as inputs, the temperature effect of a specific greenhouse gas concentration (climate sensitivity) varies depending on the model used.

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The representation of clouds is one of the main sources of uncertainty in presentgeneration models.

Global climate model projections of future climate most often have used estimates of greenhouse

gas

emissions

from

the

IPCC Special

Report

on

Emissions

Scenarios (SRES). In addition to human-caused emissions, some models also include a simulation of the carbon cycle; this generally shows a positive feedback, though this response

is

uncertain.

Some

observational

studies

also

show

a

positive

feedback. Including uncertainties in future greenhouse gas concentrations and climate sensitivity, the IPCC anticipates a warming of 1.1 °C to 6.4 °C (2.0 °F to 11.5 °F) by the end of the 21st century, relative to 1980–1999. Models are also used to help investigate the causes of recent climate change by comparing the observed changes to those that the models project from various natural and human-derived causes. Although these models do not unambiguously attribute the warming that occurred from approximately 1910 to 1945 to either natural variation or human effects, they do indicate that the warming since 1970 is dominated by man-made greenhouse gas emissions. The physical realism of models is tested by examining their ability to simulate current or past climates. Current climate models produce a good match to observations of global temperature changes over the last century, but do not simulate all aspects of climate. Not all effects of global warming are accurately predicted by the climate models used by the IPCC. For example, observed Arctic shrinkage has been faster than that predicted.

Environmental Effects of global warming and Regional effects of global warming Sparse records indicate that glaciers have been retreating since the early 1800s. In the 1950s measurements began that allow the monitoring of glacial mass balance, reported to the WGMS and the NSIDC. It is usually impossible to connect specific weather events to global warming. Instead, global warming is expected to cause changes in the overall distribution and intensity of events, such as changes to the frequency and intensity of heavy precipitation. Broader effects are expected to include glacial retreat, Arctic shrinkage, and worldwide sea level rise. Some effects on both the natural environment and human life are, at least in part, 103

already being attributed to global warming. A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption such as that of the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased intensity and frequency of extreme weather events are attributable in part to global warming. Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.

Social and economic effects of global warming may be exacerbated by growing population densities in affected areas. Temperate regions are projected to experience some benefits, such as fewer cold-related deaths. A summary of probable effects and recent understanding can be found in the report made for theIPCC Third Assessment Report by Working Group II. The newer IPCC Fourth Assessment Reportsummary reports that there is observational evidence for an increase in intense tropical cyclone activity in the North Atlantic Ocean since about 1970, in correlation with the increase in sea surface temperature, but that the detection of long-term trends is complicated by the quality of records prior to routine satellite observations. The summary also states that there is no clear trend in the annual worldwide number of tropical cyclones. Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999, new trade routes resulting from arctic shrinkage, possible thermohaline circulation slowing, increasingly intense (but less frequent) hurricanes and extreme weather events, ] reductions in the ozone layer, changes in agriculture yields, changes in the range of climate-dependent disease vectors, which have been linked to increases in the prevalence of malaria and dengue fever, and ocean oxygen depletion. Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans. CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004, ] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2. Heat and carbon dioxide trapped in the oceans may still take hundreds of years to be re-emitted, even after greenhouse gas emissions are eventually reduced. Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs. One study predicts 18% to 104

35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections. However, few mechanistic studies have documented extinctions due to recent climate change, and one study suggests that projected rates ofextinction are uncertain.

Economic: Economics of global warming and Low-carbon economy

Projected temperature increase for a range of stabilization scenarios (the colored bands). The black line in middle of the shaded area indicates 'best estimates'; the red and the blue lines the likely limits. From IPCC AR4.

The IPCC reports the aggregate net economic costs of damages from climate change globally (discountedto the specified year). In 2005, the average social cost of carbon from 100 peer-reviewed estimates is US$12 per tonne of CO2, but range -$3 to $95/tCO2. The IPCC's gives these cost estimates with the caveats, "Aggregate estimates of costs mask significant differences in impacts across sectors, regions and populations and very likely underestimate damage costs because they cannot include many non-quantifiable impacts." One widely publicized report on potential economic impact is the Stern Review, written by Sir Nicholas Stern. It suggests that extreme weather might reduce global gross domestic product by up to one percent, and that in a worst-case scenario global per capita consumption could fall by the equivalent of 20 percent. The response to the Stern Review was mixed. The Review's methodology, advocacy and conclusions were criticized by several economists, including Richard Tol, Gary Yohe, Robert Mendelsohn and William Nordhaus. Economists that have generally supported the Review include Terry Barker, William Cline, and Frank 105

Ackerman. According to Barker, the costs of mitigating climate change are 'insignificant' relative to the risks of unmitigated climate change. According to United Nations Environment Programme (UNEP), economic sectors likely to face difficulties related to climate change includebanks, agriculture, transport and others. Developing countries dependent upon agriculture will be particularly harmed by global warming.

Responses to global warming The broad agreement among climate scientists that global temperatures will continue to increase has led some nations, states, corporations and individuals to implement responses. These responses to global warming can be divided into mitigation of the causes and effects of global warming, adaptation to the changing global environment, and geoengineering to reverse global warming.

Carbon capture and storage (CCS) is an approach to mitigation. Emissions may be sequestered from fossil fuel power plants, or removed during processing in hydrogen production. When used on plants, it is known as bio-energy with carbon capture and storage.

Mitigation of global warming is accomplished through reductions in the rate of anthropogenic greenhouse gas release. Models suggest that mitigation can quickly begin to slow global warming, but that temperatures will appreciably decrease only after several centuries. The world's primary international agreement on reducing greenhouse gas emissions is the Kyoto Protocol, an amendment to the UNFCCC negotiated in 1997. The Protocol now covers more than 160 countries and over 55 percent of global greenhouse gas emissions. As of June 2009, only the United States, historically the world's largest emitter of greenhouse gases, has refused to ratify the treaty. The treaty expires in 2012. International talks began in May 2007 on a future treaty to succeed the current one. UN negotiations are now gathering pace in advance of a meeting in Copenhagen in December 2009.

Many environmental groups encourage individual action against global warming, as well as community and regional actions. Others have suggested a quota on worldwide fossil fuel production, citing a direct link between fossil fuel production and CO 2 emissions.

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There has also been business action on climate change, including efforts to improve energy efficiency and limited moves towards use of alternative fuels. In January 2005 the European Union introduced its European Union Emission Trading Scheme, through which companies in conjunction with government agree to cap their emissions or to purchase credits from those below their allowances. Australia announced its Carbon Pollution Reduction Scheme in 2008. United States President Barack Obama has announced plans to introduce an economy-wide cap and trade scheme.

The IPCC's Working Group III is responsible for crafting reports on mitigation of global warming and the costs and benefits of different approaches. The 2007 IPCC Fourth Assessment Report concludes that no one technology or sector can be completely responsible for mitigating future warming. They find there are key practices and technologies in various sectors, such as energy supply, transportation, industry, and agriculture, that should be implemented to reduced global emissions. They estimate that stabilization of carbon dioxide equivalent between 445 and 710 ppm by 2030 will result in between a 0.6 percent increase and three percent decrease in global gross domestic product.

Adaptation: Adaptation to global warming A wide variety of measures have been suggested for adaptation to global warming.

These

measures

range

conditioning equipment,

to

from

the

trivial,

such

as

major infrastructure projects,

the such

installation as

of air-

abandoning

settlements threatened by sea level rise.

Measures including water conservation, water rationing, adaptive agricultural practices, construction of flood defences, Martian colonization, changes to medical care, and interventions to protect threatened species have all been suggested. A wide-ranging study of the possible opportunities for adaptation of infrastructure has been published by the Institute of Mechanical Engineers.

Geoengineering Geoengineering is the deliberate modification of Earth's natural environment on a large scale to suit human needs. An example isgreenhouse gas remediation, which removes 107

greenhouse

gases

sequestration techniques

from such

the

atmosphere,

ascarbon

dioxide

air

usually capture.

through carbon Solar

radiation

management reduces absorbed solar radiation, such as by the addition of stratospheric sulfur aerosols or cool roof techniques. No large-scale geoengineering projects have yet been undertaken.

Debate and skepticism Increased publicity of the scientific findings surrounding global warming has resulted in political and economic debate. Poor regions, particularly Africa, appear at greatest risk from the projected effects of global warming, while their emissions have been small compared to the developed world. The exemption of developing countries from Kyoto Protocol restrictions has been used to justify non-ratification by the U.S. and a previous Australian Government. (Australia has since ratified the Kyoto protocol.) Another point of contention is the degree to which emerging economies such as India and China should be expected to constrain their emissions. The U.S. contends that if it must bear the cost of reducing emissions, then China should do the same since China's gross national CO2 emissions now exceed those of the U.S. China has contended that it is less obligated to reduce emissions since its per capita responsibility and per capita emissions are less that of the U.S.[121] India, also exempt, has made similar contentions.

In 2007–2008 Gallup Polls surveyed 127 countries. Over a third of the world's population were unaware of global warming, with developing countries less aware than developed, and Africa the least aware. Of those aware, Latin America leads in belief that temperature changes are a result of human activities while Africa, parts of Asia and the Middle East, and a few countries from the Former Soviet Union lead in the opposite belief. In the western world, opinions over the concept and the appropriate responses are divided. Nick Pidgeon of Cardiff University finds that "results show the different stages of engagement about global warming on each side of the Atlantic"; where Europe debates the appropriate responses while the United States debates whether climate change is happening.

Debates weigh the benefits of limiting industrial emissions of greenhouse gases against the costs that such changes would entail. Using economic incentives, alternative and 108

renewable energy have been promoted to reduce emissions while building infrastructure. Business-centered organizations such as the Competitive Enterprise Institute, conservative commentators, and companies such as ExxonMobil have downplayed IPCC climate change scenarios, funded scientists who disagree with the scientific consensus, and provided their own projections of the economic cost of stricter controls. Environmental organizations and public figures have emphasized changes in the current climate and the risks they entail, while promoting adaptation to changes in infrastructural needs and emissions reductions. Some fossil fuel companies have scaled back their efforts in recent years, or called for policies to reduce global warming. Some global warming skeptics in the science or political communities dispute all or some of the global warming scientific consensus, questioning whether global warming is actually occurring, whether human activity has contributed significantly to the warming, and the magnitude of the threat posed by global warming. Prominent global warming

skeptics

include Richard

Lindzen, Fred

Singer, Patrick

Michaels,John

Christy, Stephen McIntyre and Robert Balling.

Greenhouse effect The "greenhouse effect" is the warming that happens when certain gases in Earth's atmosphere trap heat. These gases let in light but keep heat from escaping, like the glass walls of a greenhouse. First, sunlight shines onto the Earth's surface, where it is absorbed and then radiates back into the atmosphere as heat. In the atmosphere, “greenhouse” gases trap some of this heat, and the rest escapes into space. The more greenhouse gases are in the atmosphere, the more heat gets trapped.

Scientists have known about the greenhouse effect since 1824, when Joseph Fourier calculated that the Earth would be much colder if it had no atmosphere. This greenhouse effect is what keeps the Earth's climate livable. Without it, the Earth's surface would be an average of about 60 degrees Fahrenheit cooler. In 1895, the Swedish chemist Svante Arrhenius discovered that humans could enhance the greenhouse effect by making carbon dioxide, a greenhouse gas. He kicked off 100 years of climate research that has given us a sophisticated understanding of global 109

warming. Levels of greenhouse gases (GHGs) have gone up and down over the Earth's history, but they have been fairly constant for the past few thousand years. Global average temperatures have stayed fairly constant over that time as well, until recently.

Through the burning of fossil fuels and other GHG emissions, humans are enhancing the greenhouse effect and warming Earth.

Scientists often use the term "climate change" instead of global warming. This is because as the Earth's average temperature climbs, winds and ocean currents move heat around the globe in ways that can cool some areas, warm others, and change the amount of rain and snow falling. As a result, the climate changes differently in different areas. Aren't temperature changes natural? The average global temperature and concentrations of carbon dioxide (one of the major greenhouse gases) have fluctuated on a cycle of hundreds of thousands of years as the Earth's position relative to the sun has

varied.

As

a

result,

ice

ages

have

come

and

gone.

However, for thousands of years now, emissions of GHGs to the atmosphere have been balanced out by GHGs that are naturally absorbed. As a result, GHG concentrations and temperature have been fairly stable. This stability has allowed human civilization to develop within a consistent climate.

Occasionally, other factors briefly influence global temperatures. Volcanic eruptions, for example, emit particles that temporarily cool the Earth's surface. But these have no lasting effect beyond a few years. Other cycles, such as El Niño, also work on fairly short and predictable cycles. Now, humans have increased the amount of carbon dioxide in the atmosphere by more than a third since the industrial revolution. Changes this large have historically taken thousands of years, but are now happening over the course of decades.

Global Warming Solutions Even if we stopped emitting greenhouse gases (GHGs) today, the Earth would still warm by another degree Fahrenheit or so. But what we do from today forward makes a big difference. Depending on our choices, scientists predict that the Earth could 110

eventually warm by as little as 2.5 degrees or as much as 10 degrees Fahrenheit.

A commonly cited goal is to stabilize GHG concentrations around 450-550 parts per million (ppm), or about twice pre-industrial levels. This is the point at which many believe the most damaging impacts of climate change can be avoided.

Current

concentrations are about 380 ppm, which means there isn't much time to lose.

According to the IPCC, we'd have to reduce GHG emissions by 50% to 80% of what they're on track to be in the next century to reach this level.

GLOBAL WARMING AWARENESS Global Warming Skeptics - Skeptics of global warming think that global warming is not an ecological trouble.

Causes of Global Warming – The Green house gases are the main culprits of the global warming. The green house gases like carbon dioxide, methane, and nitrous oxide are playing hazards in the present times. Green House Gasses are the ingredients of the atmosphere that add to the greenhouse effect.

Al Gore Global Warming Initiative - Gore has written a book that archives his advice that Earth is dashing toward an immensely warmer future.

The average facade temperature of the globe has augmented more than 1 degree Fahrenheit since 1900 and the speed of warming has been almost three folds the century long average since 1970. This increase in earth’s average temperature is called Global warming. More or less all specialists studying the climate record of the earth have the same opinion now that human actions, mainly the discharge of green house gases from smokestacks, vehicles, and burning forests, are perhaps the leading power driving the fashion.

111

The gases append to the planet's normal greenhouse effect, permitting sunlight in, but stopping some of the ensuing heat from radiating back to space. Based on the study on past climate shifts, notes of current situations, and computer simulations, many climate scientists say that lacking of big curbs in greenhouse gas discharges, the 21st century might see temperatures rise of about 3 to 8 degrees, climate patterns piercingly shift, ice sheets contract and seas rise several feet. With the probable exemption of one more world war, a huge asteroid, or a fatal plague, global warming may be the only most danger to our planet earth.

Global Warming Causes As said, the major cause of global warming is the emission of green house gases like carbon dioxide, methane, nitrous oxide etc into the atmosphere.The major source of carbon dioxide is the power plants. These power plants emit large amounts of carbon dioxide produced from burning of fossil fuels for the purpose of electricity generation. About twenty percent of carbon dioxide emitted in the atmosphere comes from burning of gasoline in the engines of the vehicles. This is true for most of the developed countries. Buildings, both commercial and residential represent a larger source of global warming pollution than cars and trucks.

Building of these structures require a lot of fuel to be burnt which emits a large amount of carbon dioxide in the atmosphere. Methane is more than 20 times as effectual as CO2 at entrapping heat in the atmosphere. Methane is obtained from resources such as rice paddies, bovine flatulence, bacteria in bogs and fossil fuel manufacture. When fields are flooded, anaerobic situation build up and the organic matter in the soil decays, releasing methane to the atmosphere. The main sources of nitrous oxide include nylon and nitric acid production, cars with catalytic converters, the use of fertilizers in agriculture and the burning of organic matter. Another cause of global warming is 112

deforestation that is caused by cutting and burning of forests for the purpose of residence and industrialization.

Global Warming is Inspiring Scientists to Fight for Awareness Scientists all over the world are making predictions about the ill effects of Global warming and connecting some of the events that have taken place in the pat few decades as an alarm of global warming. The effect of global warming is increasing the average temperature of the earth. A rise in earth’s temperatures can in turn root to other alterations in the ecology, including an increasing sea level and modifying the quantity and pattern of rainfall.

These modifications may boost the occurrence and concentration of severe climate events, such as floods, famines, heat waves, tornados, and twisters. Other consequences may comprise of higher or lower agricultural outputs, glacier melting, lesser summer stream flows, genus extinctions and rise in the ranges of disease vectors. As an effect of global warming species like golden toad, harlequin frog of Costa Rica has already become extinct. There are number of species that have a threat of disappearing soon as an effect of global warming. As an effect of global warming various new diseases have emerged lately. These diseases are occurring frequently due to the increase in earths average temperature since the bacteria can survive better in elevated temperatures and even multiplies faster when the conditions are favorable.

The global warming is extending the distribution of mosquitoes due to the increase in 113

humidity levels and their frequent growth in warmer atmosphere. Various diseases due to ebola, hanta and machupo virus are expected due to warmer climates.

The marine life is also very sensitive to the increase in temperatures. The effect of global warming will definitely be seen on some species in the water. A survey was made in which the marine life reacted significantly to the changes in water temperatures. It is expected that many species will die off or become extinct due to the increase in the temperatures of the water, whereas various other species, which prefer warmer waters, will increase tremendously. Perhaps the most disturbing changes are expected in the coral reefs that are expected to die off as an effect of global warming. The global warming is expected to cause irreversible changes in the ecosystem and the behavior of animals.

A group of scientists have recently reported on the surprisingly speedy rise in the discharge of carbon and methane release from frozen tundra in Siberia, now starting to melt because of human cause increases in earth’s temperature. The scientists tell us that the tundra is in danger of melting holds an amount of extra global warming pollution that is equivalent to the net amount that is previously in the earth's atmosphere.

Likewise, earlier one more team of scientists reported that the in a single year Greenland witnessed 32 glacial earthquakes between 4.6 and 5.1 on the Richter scale.

This is a disturbing sign and points that a huge destabilization that may now be in progress deep within the second biggest accretion of ice on the planet. This ice would be enough to raise sea level 20 feet worldwide if it broke up and slipped into the sea.

Each day passing brings yet new proof that we are now in front of a global emergency, a climate emergency that needs instant action to piercingly decrease carbon dioxide emissions worldwide in order to turn down the earth's rising temperatures and avoid any catastrophe.

It is not easy to attach any particular events to global warming, but studies prove the fact that human activities are increasing the earth’s temperature. Even though most predictions focus on the epoch up to 2100, even if no further greenhouse gases were discharged after this date, global warming and sea level would be likely to go on to rise

114

for more than a millennium, since carbon dioxide has a long average atmospheric life span.

You Can Help Fight Global Warming Many efforts are being made by various nations to cut down the rate of global warming. One such effort is the Kyoto agreement that has been made between various nations to reduce the emissions of various green house gases. Also many non profit organizations are working for the cause. Al Gore was one of the foremost U.S. politicians to heave an alarm about the hazards of global warming. He has produced a significantly acclaimed documentary movie called "An Inconvenient Truth," and written a book that archives his advice that Earth is dashing toward an immensely warmer future. Al Gore, the former vice president of United States has given various speeches to raise an awareness of global warming. He has warned people about the ill effects of Global warming and its remedies.

But an interesting side of the global warming episode is that there are people who do not consider global warming as something that is creating a problem. Skeptics of global warming think that global warming is not an ecological trouble. According to the global warming skeptics, the recent enhancement in the earth's average temperature is no reason for alarm. According to them earth's coastlines and polar ice caps are not at a risk of vanishing. Global warming skeptics consider that the weather models used to establish global warming and to forecast its impacts are distorted. According to the models, if calculations are made the last few decades must have been much worse as compared to actually happened to be. Most of the global warming skeptics believe that the global warming is not actually occurring. They stress on the fact the climatic conditions vary because of volcanism, the obliquity cycle, changes in solar output, and internal variability. Also the warming can be due to the variation in cloud cover, which in turn is responsible for the temperatures on the earth. The variations are also a result of cosmic ray flux that is modulated by the solar magnetic cycles.

Global Warming Skeptics 115

The global warming skeptics are of the view that the global warming is a good phenomenon and should not be stopped. There are various benefits of global warming according to them. According to the skeptics, the global warming will increase humidity in tropical deserts. Also the higher levels of carbon dioxide in the atmosphere trigger plant growth. As predicted, due to the global warming the sea levels will rise. But this can be readily adapted. Another argument of global warming skeptics is that earth has been warmer than today as seen in its history. The thought is that global warming is nothing to get afraid of because it just takes us back to a more natural set of environment of the past. Animals and plants appeared to do just fine in those eras of warm climate on the earth. According to few skeptics, the present chilly climate on the earth is an abnormality when judged over the geographical scale. Over geologic time, the earth’s mean temperature is 22 degrees C, as compared to today's 15.5 degrees C. Prevention for Global Warming Global warming refers to the Earth’s air and oceans gradually heating up to a point that disrupts balance, a problem that is continually getting worse. It sounds like a problem too massive for any one individual to take on, but it really isn’t. Combining any few of these suggestions can make more of a dramatic effect than most people understand.

The goal is to emit less carbon dioxide into the atmosphere: 1. Drive less. Take bikes, walk or carpool whenever possible.

2. Consider investing in a hybrid or electric vehicle to help prevent against further global warming.

3. Replace all the lightbulbs in and around your home with energy-efficient fluorescents that use fewer watts for the same amount of light.

4. Clean or replace your filters monthly.

5. Choose energy-efficient appliances when it's time to buy new ones.

6. Decrease your air travel.

7. Wash clothes in cold water and line-dry whenever possible.

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8. Use a low-flow showerhead, which will lessen the hot water used but not drop your water pressure in the shower.

9. Cut down on your garbage—buy fewer packaged materials to prevent further global warming.

10. Unplug electronics when they are not in use, because they still take up energy.

At the very least, turn items off when they’re not being used.

11. Run the dishwasher and clothes washer only when you have a full load, and if available, use the energy-saving setting.

12. Insulate your home better, and don’t forget to repair or replace worn caulking or weather-stripping. Insulate your water heater.

13. Buy recycled paper products and recycle as much of your waste as possible.

14. Bring your own reusable canvas grocery bags when grocery shopping.

15. Plant a tree.

16. Have an energy audit done on your home so you can find the trouble areas and fix them.

17. Use nontoxic cleaning products.

18. Shop locally for food. A farmer’s market is an excellent place to visit. And choose fresh food over frozen foods. Fresh takes less energy to produce.

19. Keep your car tuned up, and check tire pressure often to save gas.

20. Eat less meat and more organic foods in your diet to do your part in preventing global warming.

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CHAPTER 6 RESEARCH The objective of the research is to study the degree of awareness about environmental issues in people in semi-urban & rural area and different modes to promote it according to them in terms of their opinion & knowledge.

1. NEED FOR STUDY As a part of the course curriculum, this

project for Indian Institute of Ecology &

Environment will do lot of value additions for my profile. I will be learning in great detail the global environmental issues such as Ozone Depletion, Acid rain, Global warming, Climate change etc. Meeting with the different kinds of people and asking them about these issues will provide deeper insights into the various aspects related to environmental studies and their efforts towards maintaining and growing green & environment-friendly base. I will also be doing some value additions as this research will provide some useful information which will help in future decision making.

OBJECTIVES OF STUDY •

To study the degree of awareness in the society/ people about global environmental issues in semi-urban & rural areas.

•

To study & find out different modes of promotion of these issues .

SCOPE OF OBJECTIVES In order to achieve my objective there were some other tasks as well which were important. In order to study the global environmental issues, I went through different books provided by the institute and done several searches on internet. The information provided by my guide is also very helpful for this project. In order to do research and analyse the people, I visited several schools, offices & working places, houses in the semi-urban and rural area, sat with them over there and understood the awareness and knowledge with them about various environmental issues. I also gathered information 118

by asking them personally their suggestions with the help of self prepared questionnaire..

RESEARCH (SURVEY) METHODOLOGY Research Objective People are the asset of any society, especially in India. They consume and experience the environment’s different resources and generate the revenue from it to be a profitable preposition. But this consumption is crossing the limits put by nature. The excess use of all the natural resources is one of the main reasons for the environmental issues.

The objectives are: 1. To study the degree of awareness in the society/ people about global environmental issues in semi-urban & rural areas.

2. To study & find out different modes of promotion of these issues .

Research Plan Involves decision on the data source, research approach, research instruments, sampling plan and contact method Sources of Data Collection Sources of primary data has been used for the survey, Fresh data has been collected for this Specific purpose.

Research Approach An interview with people of different semi-urban and rural areas conducted in different schools, offices & working places, houses etc. The different kinds of people interviewed are students, working professionals, housewives and senior citizens.

RESEARCH INSTRUMENT There are basically three main research instruments in collecting primary data - Interview, Questionnaires and Qualitative measures.

In this particular research, I have used Questionnaire as a principal research instruments.

Questionnaire

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A Questionnaire consists of set of questions, presented to respondents. Because of its flexibility, it becomes the common instrument to collect primary data. My questionnaire was consisting of both close as well as open ended questions giving respondents the freedom to express their views in all possible ways.

DATA ANALYSIS GLOBAL ENVIRONMENTAL ISSUES The people interviewed can be categorized as: male & female as well as literates and illiterates. The questions were asked in their local language for their understanding.

Total no. of people interviewed (no. of samples): 200 QUESTIONNAIRE USED FOR THE SURVEY OF

PEOPLE IN SEMI-URBAN &

RURAL AREA: 1. What is your age: a) less than 20

b) 20-40

c) 40-60

d) 60 above

2. Type of Area of living: a) Rural

b) Semi-urban

3. What is your working state : a) student

b) working professional

c) housewife

d) retired person

4. Are you aware of different global environmental issues? a) Yes

b) No

5. Which global environmental issues of the following you are aware of? a) climate change

b) Global warming

c) sea level rise

d) greenhouse effect

e) Acid rain

f) Ozone depletion

g) Pollution

h) Resource depletion

i) Land degradation

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6. From which of the following source you came to know about global environmental issues? a) Newspaper

b) TV channels & movies

c) Academic books

d) Internet

e) Radio

f) Word of mouth

7. Are you aware of recent copenhegan conference held about global climate change? a) Yes

b) No

8. In what way, would you like to contribute the nature in reducing global warming and other environmental issues? (Rank the following accordingly such as 1 for most preferred) a) Use of renewable energy sources

b) Use solar energy

c) Use wind energy

d) Use nuclear energy

e) Reduce use of CO2 & CFC emitting devices f) Use pollution control equipments g) Plant more trees

h) Use of recycled products

9. Do you think that the awareness created about the global environmental issues is enough to motivate the people for its control measures? a) Yes

b) No

10. Which mode of Environmental education the following would you prefer ? (Rank the following accordingly such as 1 for most preferred) a) Newspaper

b) TV channels and movies

c) Radio

d) Internet

e) As an academic subject in school 11. What, according to you, are the factors responsible for these global environmental issues?

12. What suggestions would you like to give regarding these issues?

DATA ANALYSIS 121

One of the important steps in the process is to extract findings from the collected data.

In this research quantitative and qualitative methods of data analysis are used.

Interview questions were related to the knowledge about the environmental issues.

Quantitative analysis was done with the help of tools like MS-excel, MS-word etc.

Q.1 Age of the respondent:

Finding: most people interviewed are between age group of 20 to 40 which consists of young generation.

Q.2 Type of Area of living

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Finding: From the diagram, its clear that 112 people from rural area and 88 people from semi-urban area are surveyed. Thus, total 200 people were interviewed.

Q.3 Working state of respondents :

Finding: above diagram shows that the majority of respondents are students (84 out of 200) Q.4 Awareness about different global environmental issues 123

It is found that almost all the respondents were aware about global environmental issues due to easy modes of communication.

Q5. Different Global environmental issues respondents are aware of:

Finding: from the figure, it is clear that pollution is known to everybody interviewed.

But the issues such as acid rain & resource depletion are known by almost 74% people.

Thus, there is strong need to create awareness regarding this type of issues in rural as well as semi-urban area.

6. Source of knowledge about global environmental issues

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Finding: the main source of awareness among people is academic books of students.

TV channels and movies, newspapers upto some extent are also the important modes.

As compared to semi-urban area, rural area people lack in use of internet. Illiterate people came to know about these issues through word of mouth and through their children or grandchildren.

Q.7 Awareness about recent copenhegan conference held about global climate change Finding: out of 200 respondents, 83.5% (i.e. 167) people are aware of the recent copenhegan conference.

Q.8 The way respondents would like to contribute the nature in reducing global warming and other environmental issues (Rank: 1 for most preferred)

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Finding: option of planting more trees has got highest no. of preferences. Then second preference is to use of solar energy. Third preference is to use of renewable energy sources, as shown in figure.

Q.9 Most people(124 out of 200) think that the awareness created about the global environmental issues is quite enough to motivate them for its control measures. But still there is a large no. of people who are not satisfied with the current awareness & seriousness level in society about these issues.

Q.10 Most preferred mode of Environmental education by respondents

Finding: most preferred mode of environmental education is as an academic subject in schools and colleges. TV programs, movies and internet are mostly preferred by students and working professional preffered internet and newspapers. where as senior citizens & housewives prefer newspapers and radio.

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RECOMMENDATIONS/ SUGGESTIONS FROM PEOPLE Some main reasons behind these global environmental issues are Industrialization, deforestation, fossil fuel burning, excess use of natural resources etc. some people also feel that rapid Globalization and new technologies also contribute to the extent in destruction of earth’s natural environment.

From this survey, following are the suggestions from the people: •

Strict rules & regulations should be made and followed by government.

•

Promotion should be made through road shows, plays in schools & colleges, movies in local language, arranging different awareness camps, newspaper articles etc.

•

Give some rewards to people who use more environment friendly products.

•

Completely ban the plastic & plastic products. Give rise to use of recycled products.

•

Proper disposal of Industrial & other wastes. Rural & semi-urban people still face the problem regarding household wastes. They don’t know where to decompose the wastes as government has not provided any particular place or wastes collecting vans in these areas. Due to this, people throw their household garbage & dustbins on roadsides or in front of their homes, thus giving invitation to various diseases. This contributes to air pollution. So, waste management technology should be developed.

•

Fine or punishment to people who break the environmental rules.

•

Limit should be put on the emission of harmful gases such as CO2, CFC etc. on Industries & fine if rule is not followed.

•

The subject should be taught in schools as well as colleges at various levels.

•

Research can be done on management of harmful gases, different wastes etc.

•

Plantation should be motivated in society.

•

Controlled use of limited natural resources & use renewable energy resources.

•

Use of different pollution controlling equipments and technology

LIMITATIONS OF THE STUDY 127

•

Time constraint: Time always has some limits and often hampers and adequate field canvassing or its direction. This has particularly grave effects on the ability to reach the certain respondents that would fulfill the sampling plans

•

Money matters: It was difficult to visit the more areas if required because of the travelling expenditure involved. Money virtually always falls short of what ideal field work would cast and may require short cuts that jeopardize the validity of the findings.

•

Less time given by some respondents.

•

Some respondents don’t use internet due to unavailability.

•

Busy schedule of working professionals.

CONCLUSION From this research, it is clear that current awareness level about global environmental issues in society is quite low, especially in rural and semi-urban area. To create more awareness, high level of promotional efforts is needed for sustainable existence of human beings in future.

CHAPTER 7 CONCLUDING CHAPTERS 128

CONCLUSION Global Warming and other global environmental issues such as acid rain, climate change, sea level rise, ozone hole etc. are a dramatically urgent and serious problems.

We don't need to wait for governments to find a solution for these problems. Each individual can bring an important help adopting a more responsible lifestyle: starting from little, everyday things. It's the only reasonable way to save our planet, before it is too late.

We should Protect and conserve forest. worldwide Forests play a critical role in global environmental issues: they store carbon. When forests are burned or cut down, their stored carbon is release into the atmosphere - deforestation now accounts for about 20% of carbon dioxide emissions each year.

We should try to make our city cool Cities and states around the country have taken action to stop global warming and other issues by passing innovative transportation and energy saving legislation.

We have to make sufficient promotional efforts. People must have a stronger commitment from their government in order to stop global warming and other issues related to global environment and implement solutions and such a commitment won’t come without a dramatic increase in citizen lobbying for new laws with teeth..

LIMITATIONS OF STUDY

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1. There are more issues related to global environment. Considering all these issues is time consuming and lengthy process. So, some issues are not considered in the study.

2. Only rural and semi-urban area is considered in research. Urban city people are not interviewed.

3. Date is not advanced as dependency on internet is more.

SCOPE OF STUDY 1. Creating environmental awareness and education.

2. Promotion of awareness 3. Promotion of environmental research 4. Efficient use of natural living resources 5. Promoting plantation, use of eco-friendly products

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APPENDIX

BOOKS 1. Environmental management by N.K. Uberoi, Exel books, Delhi 2. Environmental management by Bala Krishnamurthy 3. Acedimic books provided by institute

WEBSITES 1. www.google.com 2. www.yahoo.com 3. www.telegraph.co.uk 4. www.thinkquest.org 5. www.news.scotsman.com

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