read the entire series online at presidentsclimatecommitment.org/viewpoints
004 june 2012
Fast Forward: Latest Climate Science Shows Human Society Facing Greater Risks from Global Warming Sooner Than Predicted in 2007 IPCC Report Viewpoints on Sustainability from Second Nature By Dianne Dumanoski
Dianne Dumanoski is an award-winning journalist and author who has reported on a wide range of environmental and energy issues for broadcast and print media since the first Earth Day in 1970. While working for The Boston Globe, she was among the pioneers reporting on a new generation of global threats, including global warming, and covered the 1992 Earth Summit in Rio. She is the co-author of Our Stolen Future, a seminal work on the health effects of synthetic chemicals that act as endocrine disruptors. Her latest book, The End of the Long Summer, explores what revolutionary changes in climate may mean for the kind of complex civilization humans have developed over the past 6,000 years.
The steady stream of new evidence about the dramatic physical changes across the Earth makes it harder to avoid urgent questions about what lies ahead for today’s college students. The odds are increasingly slim that their future will be some improved — but largely familiar — version of life as we know it. Given the current trajectory and political inaction, they will likely face challenges we can hardly begin to imagine in a radically altered, unrecognizable world.
Education for Sustainability
the lead supporting organization of the
The danger is great because our way of life depends on a stable climate. Ice cores from Greenland and Antarctica tell us we live at a truly extraordinary time within the Earth’s volatile climate history. Through most of our species’ 200,000-year existence, our ancestors had to cope with a chaotic climate marked by extreme variability, a climate that could not support agriculture. The world as we know it, with agriculture, civilization, and dense human numbers, has only been possible because of a rare interlude of climatic grace––a “long summer” of unusual climatic stability over the past 11,700 years.
The 2007 scientific assessment by the Intergovernmental Panel on Climate Change (IPCC), a process involving thousands of leading climate scientists from around the world, analyzed and synthesized peer-reviewed studies up to 2005. In the seven years since, a flood of new studies and reports underscores the magnitude and increasing speed of changes that are propelling us toward the unthink“The steady stream of new evidence about the dramatic able. •
will set off irreversible melting of the Greenland ice sheet The water cycle has been changing twice as fast as previously predicted
physical changes taking place across the Earth makes it harder to avoid urgent questions about what lies ahead for today’s college students.”
Growth in GHG emissions in now tracking the IPCC’s worst-case scenario Concentration of CO2 in the atmosphere of 393 parts per million is the highest in at least the past 800,000 years (modern humans emerged only 200,000 years ago) IPCC forecasts estimated that summer sea ice in the Arctic would be gone by 2070 to 2100; scientists now anticipate it to be ice-free by 2030 or sooner The oceans are warming 50% faster than reported in the IPCC report and accelerating In 2007, the IPCC projected a 2-foot rise in sea level by 2100; in a 2009 update, they upped in to a meter “or more”; today, scientists warn that we should expect sea level rise of six feet or more Oceans are becoming more acidic at the fastest rate in 300 million years Only half as much warming as previously thought
The gargantuan size of our modern industrial civilization is now disrupting our planet’s very metabolism— the vast overarching process that maintains all of earthly life. Because of humanity’s planetary impact, this exceptional moment on Earth–– with its unusually stable climate –– is drawing to a close. The human enterprise has become a risky agent of global change. The consequences in the decades ahead will depend on two things: what we do and how the Earth responds. Unfortunately, the trends on both counts have been going from bad to worse and accelerating. Instead of eliminating the greenhouse gases fueling climate change, the global economy has been pumping them into the atmosphere at an unprecedented rate with little pause from the severe global economic recession brought on
A ME RICA N C OLL EGE & U NIVERSITY
P RE S I DEN TS’ C LI MATE COM M IT M E N T
by the 2008 financial crisis. At the same time, the impacts on the Earth system are proving faster and nastier than the world’s leading climate scientists anticipated just a few years ago.
WHAT WE ARE DOING Carbon Dioxide Emissions Annual growth rate: now
three times higher than in 1990s. In 2010, as the world economy rebounded from the recession, global emissions rose 5.9%, the biggest jump every recorded. In 2011, this growth rate ebbed back to 3.2%, but that is still higher than the average annual growth rate of about 3% in the first decade of this century (Global Carbon Project, 2011). In the 1990s, when nations pledged to address the climate threat at the Rio Earth Summit, the annual growth rate was around 1% a year. The growth in emissions in now tracking the worst-case scenario considered by the IPCC.
ecosystem collapse and agricultural failure in the tropics resulting in a 40% reduction in staple crops (Anderson, 2011). Our ability to weather the century ahead will hinge significantly on the way climate change happens. The faster the warming and the higher temperatures rise, the greater the danger of sudden, abrupt shifts in the Earth’s climate system. The Asian monsoon, which brings the rains that feed several billion people, is just one example of a critical climate pattern that is vulnerable to abrupt change. Monsoon Asia, which includes South, East, and Southeast Asia, is home to 53% of the world’s population and produces 90% of the world’s rice crop. The changing atmosphere appears to be disrupting the dynamics that generate the monsoon, which, “The world is perfectly on track for a a recent study reported, has six-degree Celsius increase in temweakened in the past 50 perature [by 2100.] Everybody, even the years. The rains have become schoolchildren, know this is a catastrophe more erratic, occurring less for all of us.” frequently and, when they do arrive, they often come in the — Fatih Birol, Chief Economist for the form of torrential downpours International Energy Agency, speaking at (Krishnan, 2012; Qui, 2008).
the Carnegie Endowment for International Peace. (Reported in Washington Post NovemScientists, who study system ber 28, 2011.) dynamics, worry that the monsoon could flip to a new state in as quickly as a year’s time— perhaps becoming fiercer, but less frequent, or shutting down entirely. The former would lead to more extreme events like the devastating 2010 deluge that flooded vast areas of Pakistan; the latter would mean no rain at all, leading to failed rice crops, plummeting food supplies, and widespread hunger and starvation (Lenton, 2008). IMPLICATIONS: It may be difficult, if not impossible,
for our current civilization to adapt and endure if current trends continue.
ATMOSPHERIC CO2—HIGHER AND HIGHER
Human activity since the Industrial Revolution has warmed the Earth by .8ºC and, because of time lags in the climate system, temperatures will rise by another .6ºC even if we stopped burning fossil fuels altogether today. Thus 1.4ºC warming in already unavoidable and the Earth is now on track for a global mean warming of 7ºC (about 11ºF) by 2100 (Allison, et. al., 2009).
The current global concentration of carbon dioxide of 393 parts per million is the highest the Earth has seen for at least the past 800,000 years. Modern humans emerged only 200,000 years ago. This is more than 40% higher than the level of 278 ppm at the start of the Industrial Revolution in 1750.
The speed and magnitude of such an increase would be unprecedented and catastrophic. Even a 4ºC warming, which could occur as early as 2060, would lead to
IMPLICATIONS: CO2 rates are rising 10 times faster
than occurred during the last great global warming episode in Earth’s history—the Paleocene-Eocene Thermal Maximum some 56 million years ago. The speed of
the current warming is unprecedented and alarming. Scientists fear the consequences for life on Earth will be harsher than anything that has come before (Cui, et al., 2011; Kump, 2011).
“Temperature rises above 2ºC will be difficult for contemporary societies to cope with, and are likely to cause major societal and environmental disruptions through the rest of the century and beyond.” — 2009 update on the 2007 report of the Intergovernmental Panel on Climate Change
ished Arctic ice cap (Francis, 2012; Jaiser 2012; Liu, 2012). The winds in the upper atmosphere are slowing and altering the jet stream, setting the stage for extreme and persistent weather patterns such as lengthy cold spells, snow storms, heat waves, and flooding episodes. These circulation changes are also responsible for frequent atmospheric blocking patterns that allow for increased cold surges into temperate areas and far more snow.
HOW EARTH IS RESPONDING Arctic Sea Ice Loss—Going, Going, Gone Soon
Summer sea ice is disappearing from the Arctic Ocean far faster than the models predicted. The most recent IPCC forecast estimated that summer sea ice in the Arctic would be gone by 2070 to 2100. But the scientists tracking the loss keep revising the likely date of disappearance: now they anticipate that an ice-free Arctic Ocean could be a reality 2030 or even sooner. The five years from 2007 to 2011 have seen the lowest summer ice coverage ever. IMPLICATIONS: The loss of Arctic sea ice has impli-
cations for global weather and the Earth at large. As white, reflective ice vanishes and is replaced by areas of darker water, the polar region will absorb more heat, causing even more melting and warming---a positive feedback that reinforces itself. The rapid changes are already disrupting ecosystems, causing erosion of the coastlines in Alaska and Siberia, and threatening the survival of many birds and mammals, including polar bears and walrus. Three studies this year link extreme weather and drought in the Northern Hemisphere to changes in atmospheric circulation in winter caused by the dimin-
Massive snowfalls (US 2011, central Europe 2012), monster floods (Pakistan 2010), episodes of bitter cold (Europe 2012), and unprecedented heat waves and drought, (Russia 2010), are now happening far more often, leading one climate scientists to describe catastrophic extreme weather as “the new normal” (Zabarenko, 2011). Ocean Warming, Acidification & Sea Level Rise— expect at least 3 times higher seas than last IPCC forecast
Seas are rising far faster than IPCC scientists last warned due to melting ice caps and glaciers and because the oceans expand as they take up heat from rising global temperatures. The ocean is warming 50% faster than reported in the 2007 IPCC report, with over half of this increase occurring since 1999, indicating that this change is accelerating (Dominques, 2008). In 2007, the IPCC projected a two-foot rise in sea level in this century, a forecast that did not include contributions from the melting of ice sheets in Antarctica and Greenland. In the 2009 update, the IPCC revised this estimate to a meter “or more”. Today, scientist studying ice sheet dynamics see glaciers accelerating. They warn that we should expect far higher sea levels by 2100—at least six feet or more. The Earth’s oceans are become more acidic at an unprecedented speed—faster than any time in the past 300 million years and 10 times faster than during the last great warming 56 million years ago. IMPLICATIONS: A three feet of sea level rise will have
far ranging effects around the world as beaches erode,
coastal margins inundate, and storms surges on higher seas drive floods much farther inland. In Bangladesh, a three-foot-sea-level rise could flood 17% of the country, where 15 million people live, and destroy half of the country’s rice-farming land. Vietnam also faces the loss of half of its rice production in the coming century, which will set off a food crisis and mass migration (Young and Pilkey, 2010). Major cities around the world will find their infrastructure threatened or simply inoperable in the decades ahead. Salt water is already contaminating coastal freshwater supplies in Thailand, Israel, China, and Vietnam; the New York City subway has already flooded; and the battering of bridges, coastal power plants, oil refineries, sewage treatment systems, coastal roads is increasing.
Antarctic & Greenland Ice Sheets—faster and faster toward the sea
Antarctica is losing ice at an accelerating rate. The largest ice stream in western Antarctica and fastest, the Pine Island Glacier, is moving over one foot an hour, reports NASA researcher Robert Bindschandler. “They are changing at magnitudes and at rates that were though impossible just 15 years ago” (Eaton, 2011). A recent paper found that a majority of the marine “Current trends in energy use will boost glaciers, which are grounded global temperatures by 3.5ºC over on the sea floor, are acceleratpreindustrial levels by 2035.” ing because warmer oceans — International Energy Agency 2010 are causing the thinning and forecast collapse of the ice shelves at their leading edges (Pritchard, 2012). These ice shelves tend to slow the flow of the ice streams toward the sea. Scientists warn that seas may not rise in a steady, linear fashion. They see evidence in ocean sediment cores that sea levels have jumped in large, rapid pulses in a matter of decades (Hansen and Sato, 2011). In Greenland, glacial flow in more than 200 outlet glaciers has increased by an average of 30% between 2000 and 2010. Scientist also report that the surface melting may be accelerating through a positive feedback as bare ice replaces snow (the darker, bare ice absorbs more the light and energy and warms faster).
Acidification and warming of the oceans will wreak havoc on marine life. A recent study has linked oyster die-offs along the Oregon and Washington coastlines to ocean acidification (Barton, 2012). Acidification poses a threat to many other species as well, notably coral reefs and salmon, which feed on small organisms that are vulnerable to the growing acidity. The jump in ocean temperature has been linked to an astonishing decline in the tiny plant plankton that are key to the ocean food web and help keep the Earth cool by removing carbon dioxide from the atmosphere for their photosynthesis. A 2010 study linked the sharp decline in worldwide plankton levels of 40% since1950 to warmer surface temperatures (Boyce, 2010). This loss of plankton at the bottom of the food web undermines the productivity of the entire ocean and threatens fisheries, marine mammals, and all life that depends on it.
The complete loss of the Greenland ice sheet may soon be inevitable. A new study concluded that it will only take half as much warming to set off irreversible melting than previously thought (Robinson, 2012). Instead of a threshold of 3.1ºC, the new best estimate is 1.6ºC (with a range of .8 to 3.2ºC). Since the world has already warmed .8ºC and is warming .2ºC a decade, there is a chance that warming will soon pass this ominous threshold. IMPLICATIONS: Faster ice loss from ice sheets means
faster and greater sea level rise and increases the chance of extreme jumps in sea levels. This will leave less time to prepare or retreat, lead to greater social and economic chaos, and make coastal areas where much of the world’s population lives uninhabitable. Total loss of the West Antarctic Ice sheet would raise sea levels by roughly 26 feet. The water stored in the Greenland Ice Sheet would cause sea level to rise by 20 feet.
Global Water Cycle—changing 2 times faster than models predicted
CLIMATE SENSITIVITY—HOW MUCH WARMING IS TOO MUCH?
Climate models predict that a faster water cycle in a hotter atmosphere will distribute moisture more unevenly according to a “rich get richer” principle. Those areas that already get lots of rain will get even more while already dry areas such as the subtropics will get even less.
Climate policy makers have assumed that limiting warming to no more than 2ºC above preindustrial levels would be enough to avoid dangerous climate change.
A new study surprised scientists by showing that the water cycle has been changing for the past half century— and changing twice as fast as climate models have been predicting (Durack, 2012). It has already accelerated by 4% during a time when the Earth has warmed .5º C. Even with 2ºC to 3ºC warming in the decades ahead, the water cycle will accelerate 16% to 24%—4 to 6 time more than it has already—“a pretty amazing projection,” as one scientist put it (Kerr, 2012). IMPLICATIONS: Extreme weather events are now
being linked both to shifting atmospheric dynamics in the Arctic and to the speed up in the water cycle. This leads to a grim long range forecast of more and worse extreme events: monster floods, killer droughts, massive snowfalls, such as those in the U.S. Northeast in early 2011 and in central Europe in 2012, violent storms, and devastating deluges, such as a 13-inch rain that devastated Nashville in May 2010. Meteorologists note that the faster the water cycle, the more heat energy moves from the surface to the atmosphere, which can fuel tornadoes, hurricanes, and other violent storms. It is likely that flooding will become more severe and frequent in already wet places. And already dry regions will face longer and more intense droughts. According to a recent studies, drought conditions will get far worse as global temperatures rise by 2.5ºC. Results from 22 state-of-art climate models and an index of drought conditions project that almost all of Mexico, most of central America, the United States Midwest, and large parts of Eurasia, Africa, and Australia will suffer extreme drought in the decades ahead. As the author of one of these studies, Aiguo Dai of the National Center for Atmospheric Research, noted: “If the projections in this study come even close to being realized, the consequences for society worldwide will be enormous.” Based on current trends, the warming will soar to 3.5ºC in 25 years (Dai, 2012).
“This jump in ocean temperature has been linked to an astonishing decline in the tiny plant plankton … A 2010 study found that worldwide plankton levels began to decline sharply in 1950 and have plummeted 40 percent since then (Boyce, 2010). In the past year, leading climate scientists have been challenging this conventional wisdom, warning that the Earth will respond far faster to warming that previously thought. “There’s evidence that climate sensitivity is quite a bit higher than what the models are suggesting,” stated Ken Caldeira, a senior scientist at
Stanford University’s Carnegie Institution for Science (Caldeira, 2011). An extensive new study of the Earth’s climate history going back 50 million years concludes that the current goal of 2ºC is “a prescription for disaster,” in the words of Jim Hansen, the director of NASA’s Goddard Institute for Space Studies (Hansen and Sato, 2011). If atmospheric CO2 rises to 450 parts per million, the level usually associated with a 2ºC warming, this latest analysis concludes that it will be enough to trigger feedback mechanisms—such as the release of frozen methane from the seas and from the thawing permafrost-- that will accelerate warming and lead to the loss of a significant part of the world’s ice sheets. IMPLICATIONS: It will require extremely rapid and radi-
cal reductions in fossil fuel use beginning immediately to preserve a planet hospitable to humans and our current complex civilization, which depends on agriculture and a stable climate. If the world begins reducing CO2 emissions by 6% a year in 2012, it can return to 350 parts per million—a “safe” level. If we delay reductions until 2020, emissions will have to come down by more than twice as fast—15% a year to reach the same level by 2050. As NASA climate scientist Jim Hansen summed it up: “We are out of time.”
As of late May 2012, 64% of the contiguous U.S. territory was abnormally dry or under drought conditions.
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Published on Jun 1, 2012
by Dianne Dumanoski Fast Forward: Latest Climate Science Shows Human Society Facing Greater Risks from Global Warming Sooner Than Predicted...