Tipping Points that Could Lead to Abrupt Climate Change 87.pdfis a point at which the climate, without additional forcing, undergoes rapid changes that are practically uncontrollable.8

Tipping Points that Could Lead to Abrupt Climate Change

IGSDIINECE Climate Briefing Note: September [], 2008

DRAFT FOR REVIEW 09/16/08

I. Introduction

A. Summary

The paleoclimate records show that past climate changes have included both steady, linear changes as well as abrupt, non-linear changes where small increases in global warming produced large and irreversible impacts once certain thresholds, or "tipping points", were passed. A non-linear tipping point is analogous to the final step one takes walking off a cliff. Once the step is taken, there is no going back. Abrupt climate change can produce potentially catastrophic impacts, such as the shutdown or reorganization of global currents, dieback of the Amazon rainforest, and collapse of the Greenland Ice Sheet. 1

Experts have concluded that anthropogenic forcing could increase the risk of abrupt climate change and that tipping points could be passed this century, or even this decade.2

If we continue emitting greenhouse gases in a "business-as-usual" scenario, permitting atmospheric carbon dioxide (C02) concentrations to rise 2-3 ppm every year, the question is not whether abrupt climate change will occur, but rather how soon it will occur.3 In fact, some experts conclude that 385 ppm, the current concentration of CO2, is already too high, and that we must return to 350 ppm if we want to preserve a planet similar to that on which civilization developed and to which humanity is adapted.4 Despite the certainty that abrupt changes have occurred in the past and could be triggered again in the near future, current climate change policy does not account for abrupt climate change. In particular, abrupt climate change is not incorporated into the projections of the Intergovernmental Panel on Climate Change (lPCC), which is regarded as the most authoritative, if often too conservative, source of information on climate issues.5

B. Definition of Abrupt Climate Change

"Abrupt climate change" is the large-scale transformation in a climate system which occurs when it is forced past a tipping point and which could lead to potentially catastrophic impacts.6 "The term 'tipping point' commonly refers to a critical threshold at which a tiny perturbation can qualitatively alter the state or development of a system.,,7 It is a point at which the climate, without additional forcing, undergoes rapid changes that are practically uncontrollable. 8 Positive feedbacks, physical responses that amplify the original actions, can accelerate linear changes and push a system past a tipping point. The "point of no return" is a "climate state beyond which the consequence is inevitable, even if climate forcings are reduced.,,9 Sometimes a point of no return can be avoided even if a tipping point is exceeded, for example when greenhouse gases sufficient to raise global temperature past a critical threshold are released but their effects are delayed. 10

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University of Hawaii School of Law Library - Jon Van Dyke Archives Collection

Scientists have identified specific geographical areas, weather systems, forests, and even ocean currents that might be vulnerable to tipping points in the next century, with Arctic sea-ice, which is rapidly disappearing in summer, and the Greenland Ice Sheet, which is steadily losing mass, considered the most sensitive. II These large-scale components of the Earth system that may pass a tipping point are referred to as "tipping e1ements.,,12 In addition to Arctic sea-ice and the Greenland Ice Sheet, other tipping elements include the West Antarctic Ice Sheet, Atlantic Thermohaline Circulation, which is a global current, and Amazonian and boreal forests. Meteorological phenomena such as El Nino-Southern Oscillation and the Indian Summer Monsoon are also tipping elements affected by global temperature changes. For some of these tipping elements, there is a high degree of uncertainty as to triggers and timescales for transitions and impacts. Even for the most sensitive tipping elements, expert predictions vary as to how soon a tipping point will be passed - or if one already has been passed. The Intergovernmental Panel on Climate Change (IPCC) typically issues the most conservative estimates, some of which are considered by many experts to be out-of-date before they are even published. 13 However, the findings of the IPCC in its 2007 Fourth Assessment Report (AR4) have been frequently used as starting points or points of contrast for other experts' more current and more aggressive predictions for global warming and climate change.

II. Tipping Elements

A. Arctic Sea Ice

In both summer and winter, the presence of Arctic sea ice has declined steadily over the last 30 years, and decreases in summer sea ice in the last 3 years have been dramatic. Less ice means less snow cover, a reduction in snow albedo, or reflectivity, and more absorption of heat by exposed Arctic waters, surface pools, and darker ice, all of which lead to further warming and ice melting. 14 The ice albedo positive feedback that converts white snow and ice into slick, dark ice is sometimes referred to as "albedo flip.,,15 Aside from this positive feedback, further darkening of polar surfaces is caused when black carbon, or soot, is released into the atmosphere and falls to earth blanketing snow and ice. 16 Whereas clean snow cover bounces 70-90% of the sun rays back into space, dirty snow can absorb more than 65% of solar radiation, while dark ice and open water absorb up to 95%.17

In the AR4, which was published in December 2007, the IPCC projected that an increase of about 9°C in the Arctic could cause a disappearance of late summer sea ice before the end of the century. IS Since warming is generally over twice as strong at the highest and lowest latitudes, this would correspond with a global temperature increase of about 4°c. 19

In late 2006 and early 2007, however, many climatologists were already predicting completely ice-free Arctic summers by as early as 2030,z° Despite these predictions, the scientific community was stunned when on September 16, 2007, the Arctic sea ice coverage decreased to 4.13 million square kilometers, compared to the previous record low of 5.32 million square kilometers in 2005,z1

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The 2008 summer ice is on pace to be the second-lowest on record as of September 3, 2008 [update tomorrow] when it measured 4.85 million square kilometers, making it clear that the Arctic is now headed toward irreversible sea ice loss very quickly, with a transition to an ice-free Arctic summer expected in the next decade with a local temperature increase of only 0.5_2°C?2 Alarmingly, human activity has already raised the average global temperature 0.8°C above pre-industrial levels with another 0.6° C "in the pipeline," yet to manifest but that will be caused by pollution we have already released?3 Given the more than double sensitivity of polar latitudes - meaning an increase as small as 0.2-0.250 C globally could be enough to melt the sea ice completely - some predictions have summer sea ice making its first full retreat as early as late summer 2013.24

Summer of 2008 is also the first year that the Northwest Passage over the top of North America, and the Northeast Passage over the top of Russia are both clear of ice.25 The opening of these channels will likely significantly increase emissions in high latitudes by opening a new, shorter ocean route between Europe and Asia, "a prospect already drawing billions of dollars in investment in ice-class ships".26

Many experts adjudge that we are past the point of no return for loss of Arctic summer sea ice.27 Whether or not this is the case, when the transition occurs, the amplified warming is not only likely to heat up the regional environment - which could lead to thawing of permafrost in the Arctic tundra amongst other impacts - but also likely to hasten the melting of the Greenland Ice Sheet.28

B. Greenland Ice Sheet

Recent observations of the Greenland Ice Sheet (GIS) show that surface mass is declining, coastal ice is thinning and glaciers are experiencing surges - periods of rapid advancement - all at speeds that cannot be explained by IPCC ice sheet models.29

Warming along coasts is expected to decrease surface altitude, leading to increased warming and generating a positive feedback loop which will push the GIS fast a tipping point beyond which the ice sheet will disintegrate or contract significantly.3 Accelerating the melting on the GIS is the penetration of warm ocean waters that carve ice streams into the glaciers, sometimes permeating them down to the bottom?! The melting is also triggering earthquakes across the GIS, and the large chunks of glaciers that break off are carried out to sea by the streams.32

In light of these multiple positive feedbacks, experts predict that the GIS will reach its tipping point with a local temperature rise of 2.7_3.0°C.33 Modeling the dynamics of ice streams has proved difficult for scientists, however, and not one has yet been able to create an adequate simulation of the rapid disappearance of ice sheets at the end of the last ice age.34 Reflecting this large degree of uncertainty, the IPCC puts the tipping range for the GIS at 1.9-4.6°C global temperature raise, but even the high end of this range is easily achievable by 2100?5 Despite the lack of verifiable projections, many experts state that the GIS will probably contribute more and faster to sea level rise than demonstrated by the current models,

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which cannot even simulate the current melt rates.36 Additionally, the dramatic retreat of Arctic sea-ice in summer of 2007 made some experts revise timelines for GIS tipping points, given that the albedo flip and dark ocean water absorption could begin creating seasonal warm baths for the GIS.37 Whether it occurs with a 3°C increase globally (per IPCC) or locally (per other experts), once the point of no return is passed, a total collapse of the GIS is possible within 300 years.38 A total meltdown has the potential to cause a sea level rise of 7 meters.39 Indications are that the disintegration tipping point for the GIS may have already been passed, but if not, the world may have less than a decade to take measures to reverse the current trend.4o

C. The West Antarctic Ice Sheet

The timescale for the tipping and the transition of the West Antarctic Ice Sheet (WAIS) is even more uncertain than that of GIS, although studies indicate that the W AIS, which comprises 10% of the Antarctic ice sheet, is losing mass.41 Glaciologists have also observed that glaciers draining into the Amundsen Sea are recovering less than half of the ice they are shedding.42 Additionally, the structure of the WAIS makes it vulnerable at its base where the ice attaches it to bedrock below sea leve1.43 The W AIS therefore "has the potential to collapse if grounding-line retreat triggers a strong positive feedback whereby ocean water undercuts the ice sheet and causes further separation.,,44 Rising sea levels could also cause the ice to "unhinge ... from pinning points.,,45

Disintegration of the major ice shelves on the WAIS, Ross and Fischer-Ronne, and the formation of ice streams, may precipitate a collapse of the WAIS.46 This would be similar to the series of retreats along the Antarctic Peninsula that led to the 2002 collapse of the Larsen B ice shelf, which had been covered with ponded water and deep ice streams b c:. 47 elore It gave way.

For the complete disintegration of the WAIS, the IPCC declines to even set a timeline or temperature, although other experts estimate that a tipping point could pass this millennium, with a collapse within three centuries being the worst case scenario.48 The tipping of the WAIS would require 3-5°C global warming, much more than I-2°C warming needed to precipitate GIS melt, yet experts predict rapid sea level rise over the next century is more likely to come from melt and drainage of W AIS ice shelves than from GIS melting.49 When the WAIS does collapse, it will contribute at least 5 meters of sea level rise to the 2-7 meters of freshwater presumably already contributed by the melted GIS. 5o

D. Continental Glaciers

From the Tibetan Himalayas to the American Rockies to the Argentinean and Chilean Andes, glaciers and snowpacks are disappearing from the world's most famous peaks. Glaciers, ice caps and continental ice sheets presently cover about 10 percent of the earth's land surface and contain about three-quarter of the world's total freshwater resources. 51 Glaciers are unique sources of freshwater for agricultural, industrial and domestic use as well as hydro-electric power production. 52 Always close to the melting

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point, glaciers react to every incremental temperature increase, thereby providing some of the clearest evidence of climate change and making them important part of global warming monitoring. 53

Since the 1950's, warming in excess of 1°C on the Tibetan side of the Himalayas, has contributed to the retreat of glaciers. 54 An important factor in Himalayan glacial melting is black carbon which works both when it is airborne to heat the atmosphere, and also, once it is deposited, to darken the snow with soot, enhancing solar absorption by snow and ice. 55 Disappearances of ice caps in the Himalayas, which feed the Ganges, Indus, Brahmaputra, Salween, Mekong, Yellow and Yangtze Rivers could be catastrophic. When the dwindling Himalayan glaciers stop producing adequate run-off, it will reduce the water supply for the major Chinese and Indian rivers that irrigate rice and wheat crops that feed millions of people. 56 In the nearby Tibetan Plateau Steppe, from which the Yangtze, Mekong, and Indus begin their journeys to the sea, permafrost is degrading and causing concern that drying may lead to eventual desertification. 57

Similar glacial melting will occur around the world with warming of only 1_2°C.58 The Kilimanjaro ice sheet, which has already lost 80% of its mass, is expected to disappear completely by 2015-2020.59 A recent study shows that all of the glaciers on the Iberian Peninsula have dis~peared except for glaciers in the Pyrenees which are projected to disappear by 2050. In the European Alps, where landslides are already a problem, 1°C of warming will cause retreats of ice and thawing of permafrost, which could release methane stores.61 Recent studies indicate that most of Andean glaciers from Colombia to Chile and Argentina, including Northern and Southern Patagonia and Tierra del Fuego which contain 85% of the continent's ice cover, are drastically reducing their volume at an accelerated rate.62 With 2°C warming, experts predict that the Andes would lose another 40-60% of their glaciers by 2050.63 In North America, 2°C warming would cause the Northern Rockies to lose 70% of snowpack, and snowpack decline in California would be 25-33%.64 Rising temperatures are also predicted to reduce snow 36% by 2055 and 50% by 2090 in the Sierra Nevada, which is the source of 65% of California's developed water, as well as almost all the water to Northwestern Nevada.65

E. Atlantic Thermohaline Circulation

In addition to raising sea levels, glacial run-off also freshens and desalinates ocean waters, which could trigger a shutoff in the North Atlantic Deep Water formation and the associated Atlantic Thermohaline Circulation (THC).66 The THC is "a vast network of deep ocean currents driven by differences in temperature and salinity, circulating warm water from the tropics to the North Atlantic and making it possible for London to be warmer than Labrador, its latitudinal counterpart.,,67 Already the THC is beginning to slow down, with a recent study revealing that nearly a third of the warm water that used to flow northward remains trapped in the subtropical Atlantic. 68

It is unknown precisely how much fresh water is needed to shut down the THC, or if the transition will be abrupt or smooth, reversible or irreversible.69 The IPCC argues that an abrupt change in the THC is very unlikely, however, its models do not even take into

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account the freshening in the North Atlantic due to the melting GIS.7o Many models show that the THC will pass a tipping point in about a century with 3_5 0 C warming, but predict that the transition might be one of gradually slowing circulation.

Even though the science is uncertain, if an abrupt THC change did occur, it would be likely to have massive consequences. Scientists believe that the last two abrupt coo lings, during the Younger Dryas and the "event 8200 years before present" both occurred when huge North American glacial melt-water lakes flooded down the st. Lawrence River into the North Atlantic, causing reorganizations of the THC.71 The onset of the Younger Dryas occurred rapidly with a series of 50 F temperature drops each decade, followed by a period of 1,000 years of cold, dry weather. 72 History suggests that it is possible that the freshening of the Atlantic could cause another transition just as quickly. 73

F. EI Nino-Southern Oscillation

The EI Nifio-Southern Oscillation (ENSO) is a climate mode that occurs typically every 2-10 years with a relaxing of the tradewinds that keep warm water welled up in the Western Pacific, allowing the warm water to roll eastward, bringing rainfall to South America and the southern United States. Experts expect global warming to increase heat uptake over the ocean and amplify EI Nifio.7 A tipping point could be passed at 3-60 C, after which even a smooth and gradual transition could have large-scale impacts.75 An intensified EI Nifio would cause more flooding in Ecuador and Peru, and dangerous dryness in Southeast Asia, Australia, and the Amazon rainforest. 76 Some experts note that there is evidence that during the Pliocene Age permanent EI Nifio conditions existed, although models do not consistently show a tendency toward more frequent El Nifio conditions.77 Regardless of frequency, experts agree that the world is likely headed toward a period of amplified, "super EI Nifios.,,78

G. Indian Summer Monsoon

The Indian summer monsoon (ISM) is an annual event upon which many Asian populations depend as a primary source for water for agriculture and human consumption, but heavy rains can be perilous, causing landslides, flash floods, and crop damage, as well as human casualties and displacements. 79 While monsoon rainfall is variable year to year, studies spanning decades have shown a steady increase in strength of monsoons consistent with warming in the Northern hemisphere.8o For example, heavy rainfalls have increased in both frequency and magnitude over central India during the monsoon seasons from 1951 to 2000.81 The IPCC has also concluded that greenhouse gases will increase the yearly variability of daily precipitation. 82

The tipping point that could be closest - about a year away - is not related to local temperature increases, but rather to "planetary albedo" created by land use and release of sulfate aerosols. 83 Rather than strengthening the ISM, planetary albedo, which reflects solar radiation, weakens it significantly. The IPCC predicts that the sulfate aerosols will weaken the magnitude of precipitation change, but by the end of the century greenhouse gases will dominate. 84 However, other experts predict that the combination of local

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planetary albedo and greenhouse gases can cause a tipping point within the next year lead that will lead to widely ranging variability between active and weak states of the ISM. 85

H. Sahara/Sahel, southern and eastern Africa and West African Monsoon

The behaviors of regional monsoons and conditions over the Indian Ocean have the potential to change levels of precipitation across Africa. Most experts agree with the IPCC finding that southern Africa will experience rainfall declines, large-scale water stress and yield reductions by 2030.86 With regard to the rest of the continent, theories range widely as to whether rainfall will decrease or increase based on weather patterns and the effect of a warming Indian Ocean.

The IPCC predicts the following conditions across the continent: annual rainfall is likely to decrease in much of Mediterranean Africa and northern Sahara, and rainfall in southern Africa is likely to decrease in much of the winter rainfall region and on western margins. 87 Meanwhile, there is likely to be an increase in annual rainfall in East Africa, but is uncertain how rainfall in the Sahel, the Guinean Coast and the southern Sahara will evolve.88

With regards to the southern Sahara and Sahel, which is a belt of sub-Saharan semiarid grasslands, some expert theories diverge from those of the IPec and predict a greening of the Sahara and associated expansion of the Sahel. 89 Based on an assumption that a disruption in the West African Monsoon would allow an inflow of moisture from the west, the most likely outcome would be a regrowth of grasslands in the Sahara and shrub vegetation in the Sahel, such as existed in the mid-Holocene era.90 Other studies suggest that increased atmospheric concentrations of CO2 may cause some greening in North Africa, but that results are uncertain and depend on many other factors, such as strength of the North African Monsoon, atmosphere-vegetation interaction, and anthropogenic land use and land cover change.91

For eastern Africa, some experts dispute the IPCC prediction that rainfall levels will rebound, instead anticipating a continuation of the current trend of decline in growingseason rainfall.92 These scientists expect warming over the Indian Ocean to increase maritime precipitation and decrease continental rainfall over both southern and eastern Africa.93 This disruption of moisture transport from ocean to land could result in drought and reduction of agricultural capacity in already fragile economies in these regions.94

I. Amazon Rainforest

The tipping point for dieback of the Amazon rainforest, where 10% of the world's terrestrial photosynthesis occurs, could occur within 50 years with a temperature increase of2-40 C.95 Although the IPCC does not state a prediction in AR4 for a tipping point in the Amazon, other models predict that the effects of global warming on ENSO will reduce precipitation over the Amazon basin, leading to lengthening of the dry season in the rainforest. 96 In periods of drought, vegetation, most of which has not evolved resistance to fire, will be exposed to "mega fires.,,97 Instead of sequestering CO2 through

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photosynthesis, the rainforest could become one of the world's largest sources ifE! Nifiogenerated forest fires, which in 1998 produced 5% of global greenhouse gas emissions, begin raging habitually.98 Slash-and-burn tactics used for deforestation are likely spark or contribute to these blazes.99

J. Boreal Forests

As the Arctic warms, summer heat in the boreal forests will lead to increased vulnerability to disease and fire, which could lead to large-scale die-back and transition to open woodlands and grasslands. IOO Studies sugffiest that a tipping point exists at 3 0 C global warming for dieback of boreal forests. I I Permafrost in the boreal forests and further north in the Arctic tundra is already starting to melt and release methane that has been trapped in frozen ground for 3,000 years. 102 In addition to unleashing methane, a greenhouse gas twenty-five times as powerful as CO2, newly unfrozen soil combined with reductions in snowfall, will support more drying, more fire, and less biomass. 103

III. IMPACTS

A. Sea Level Rise

A complete collapse of the Greenland Ice Sheet has the potential to cause a sea level rise of 5-7 meters (or 2-7 meters according to the IPCC).104 The collapse of the West Antarctic Ice Sheet would contribute at least 5 meters more to sea levels. 105

The impacts of even a fraction of this dual source sea level rise would be devastating to the more than 200 million people worldwide living in coastal floodplains. l06 Many of the world's major cities (22 of the top 50) are at risk of flooding from coastal surges, including Tokyo, Shanghai, Hong Kong, Mumbai, Calcutta, Karachi, Buenos Aires, St. Petersburg, New York, Miami and London.,,107 Even before the cities are flooded, risin& sea levels would pollute aquifers with salt, putting underground water reserves at risk. 10 A sea level rise of just one meter could destroy river deltas and agricultural land in the developing world as well as overrun beaches and ports and inundate subterranean systems in developed nations. l09 Some studies suggest that small island nations may shrink in size, which would devastate infrastructure and economies, most of which is concentrated in coastal areas of islands. 110

B. Water Shortages

Rapidly melting glaciers and ice caps will initially be a source of flooding - until they melt completely, at which time the problem will become the lack of glacial run-off to regions dependent on it.

As run-off from the Himalayas weakens, the concern is that it will restrict the flow of seven of Asia's great rivers, the Ganges, Indus, Brahmaputra, Salween, Mekong, Yellow and Yangtze, and reduce the water supply for irrigation of rice and wheat crops that feed billions of people. 1I1 Warmer temperatures are also predicted to reduce snow 36% by

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2055 and 50% by 2090 in the Sierra Nevada, which is the source of 65% of California's developed water, as well as almost all the water to Northwestern Nevada. 1l2 Similarly, when glacial loss in the Andes reaches 40-60%, which is predicted to occur by 2050 with 2 0 C, summer run-off will be drastically decreased and water shortages will be horrendous for nations like Peru. l13

D. Famine

Widespread famine will be the inevitable result of disappearing glaciers and reduced runoff to feed life-sustaining rivers and lakes. As with any catastrophe, the poorest, most undernourished, and least stable populations will be hit hardest as environments become uninhabitable and food supplies shrink. A study in China of the thawing in glaciers that supply the Yellow River found that the region is experiencing vegetation loss of 3-10 percent per year. 114 In central and south America, maize losses are projected for all nations but two. liS In eastern and southern Africa, researchers have identified a trend of diminished rainfalls during the main growing season in Indian Ocean rim countries with already precarious food security.116 In 29 African countries, including Mali, Botswana and Congo, crop failure and hunger are likely to increase. I 17

C. Release of Methane from Permafrost and Ocean Hydrates

One of the most important greenhouse gases is methane, which causes the third largest human-made GHG climate forcing after CO2 and black carbon and is the principal cause of increased tropospheric ozone, which is the next largest GHG forcing. 1I8 With increased global temperatures, methane that has been trapped for thousands of years may be released from both terrestrial and oceanic sources. 119

As the Arctic heats up, permafrost in the boreal forests is starting to melt triggering methane release. 120 Methane from bogs and marshlands trapped under Siberia's permafrost, which contain 70 billion metric tons of methane, is already beginning to leak out. 121 Permafrost is defined as earth that remains frozen for more than 2 years. It has been estimated that permafrost covers 20% of the terrestrial surface of the earth. Trapped inside some permafrost is organic matter which survived decomposition because of the freezing temperatures. 122 Thawing will cause accelerated decomposition of this organic matter, increasing the output of C02 and CH4. 123

Another huge store of methane exists on the sea floor in deposits of methane hydrates, which are water ice that contain large amounts of methane within their crystal structures, called clathrate hydrates. 124 Methane is transported to water surfaces by bubbles, and the fear is that methane could escape in a dense bubble plume, or in a blowout plume, which could explain how methane from hydrates could produce abrupt climate change. 12S

F. Political Instability and Wars

If a tipping point for North Atlantic freshening is passed and a THC shutdown occurs, a sudden plunge in temperatures could catastrophically disrupt the world's natural, social,

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and economic operations. A report by the Pentagon envisions this scenario, under which Earth's "human carrying capacity" would drop significantlj and worldwide military conflicts over food, water, and energy supplies would ensue. 12

The scenario is drawn from "the cooling event 8,200 years ago" which was characterized by temperatures dropping 5° F over Asia and North America and 6° F in northern Europe and by temperatures increasing up to 4°F in areas throughout Australia, South America, and southern Africa. 127 Under these conditions, mega-droughts would debilitate agriculture in key regions in Asia, North America and Europe, and the water supplies of major cities would be cut off. 128 Food and water shortages could lead to skirmishes and even wars. Nations with adequate natural resources may isolate and fortify themselves against intrusions by less fortunate nations. 129 Meanwhile, neighboring countries that have been historically hostile would likely clash the soonest and most frequently, but instead of fighting over religion, ideolo~6 or national honor, the goal would be access to essential resources needed for survival. I

IV. Conclusion

AR4 is IPCC's strongest call yet for reduction of greenhouse gas emissions and other mitigation measures, but many experts consider the report too conservative. 131 In fact, IPCC Chairman Rajendra Pachauri has stated that he agrees that CO2 targets of 450-500 ppm are too high and that C02 must be reduced back to 350 ppm.132 Climate policy currently focuses on addressing the linear impacts of climate change, excluding nonlinear impacts that could occur when tipping points for abrupt climate changes are passed. This exclusion may be due in part to the uncertainty of involved in predicting impacts and timescales, however, the United Nations Framework Convention on Climate Change requires immediate reductions of greenhouse :rases because of the uncertainty of their impacts on the environment, not in spite of it. 13 Certain tipping elements, such as Arctic summer sea-ice, may have crossed points of no return, but fast action mitigation could prevent, or possibly reverse, tipping that would otherwise lead to devastating impacts such as floods, droughts, fires, and famines.

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I Timothy Lenton, Hermann Held, Elmar Kriegler, Jim Hall, Wolfgang Lucht, Stefan Rahmstorf, and Hans Joachim Schellnhuber, Tipping elements in the Earth's climate system, 105 PROC. OF THE NAT'L ACAD. OF SCI. 6, 1786 (12 February 2008). 2 Committee on Abrupt Climate Change, Abrupt Climate Change: Inevitable Surprises, National Academies Press, Washington, D.C., 2003, 107-8. ("Given our understanding of the climate system and of the mechanisms involved in abrupt climate change, this committee concludes that human activities could trigger abrupt climate change. Impacts cannot be predicted because current knowledge is limited, but might include changes in coupled modes of atmospheric-ocean behavior, the occurrence of droughts, and the vigor of thermohaline circulation (THC) in the North Atlantic. More research is needed to better understand the relationship between human influences on climate, especially global warming, and possible abrupt climate change."); see also Terry Barker, Igor Bashmakov, Lenny Bernstein, Jean Bogner, Peter Bosch, Rutu Dave, Ogunlade Davidson, Brian Fisher, Michael Grubb, Sujata Gupta, Kirsten Halsnaes, Bert jan Heij, Suzana Kahn Ribeiro, Shigeki Kobayashi, Mark Levine, Daniel Martino, Omar Masera Cerutti, Bert Metz, Leo Meyer, Gert-Jan Nabuurs, Adil Najam, Nebojsa Nakicenovic, Hans Holger Rogner, Joyashree Roy, Jayant Sathaye, Robert Schock, Priyaradshi Shukla, Ralph Sims, Pete Smith, Rob Swart, Dennis Tirpak, Diana Urge-Vorsatz, and Dadi Zhou, "Summary for Policymakers IPCC Fourth Assessment Report, Working Group III" (April 30, 2007), 13 ("Anthropogenic warming could lead to some impacts that are abrupt or irreversible, depending upon the rate and magnitude of the climate change.") 3 James Hansen, Climate Catastrophe, NEW SCIENTIST, 28 July 2007. 4 James Hansen, Makiko Sato, Pushker Kharecha, David Beerling, Valeris Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer, and James C. Zachos, Target Atmospheric CO2: Where Should Humanity Aim?, [date], 1 available at http://www.columbia.eduHeh1l2008/TargetC02 20080407.pdf accessed on 12 September 2008. 5 Lenton, et aI, supra note [ ], at 1792 ("Society may be lulled into a false sense of security by smooth projections of global change. Our synthesis of present knowledge suggests that a variety of tipping elements could reach their critical point within this century under anthropogenic climate change." 6 ACC: Inevitable Surprises, supra note [ ], at 14 ("Technically, an abrupt climate change occurs when the climate system is forced to cross some threshold, triggering a transition to a new state at a rate determined by the climate system itself and faster than the cause. Chaotic processes in the climate system may allow the cause of such an abrupt climate change to be undetectably small. To use this definition in a policy setting or public discussion requires some additional context, ... because while many scientists measure time on geological scales, most people are concerned with changes and their potential impacts on societal and ecological time scales. From this point of view, an abrupt change is one that takes place so rapidly and unexpectedly that human or natural systems have difficulty adapting to it.") 7 Lenton, et aI, supra note [ ], at 1792. 8 Hansen, et aI, Target Atmospheric CO2, supra note [ ], at 10. 9 Hansen, et aI, Target Atmospheric CO2 supra note [ ], at 10. 10 Ocean and ice sheet inertia cause lags in the system and permit margin for overshooting a tipping point but not passing a point of no return. Hansen, et aI, Target Atmospheric CO], supra note [ ], at 10; id, at 5 ("Since the beginning of the industrial era, the gap is widening between actual global temperature and long-term temperature response based on net estimated forcing. Ocean thermal inertia causes this lag, and ' temperature increases that are expected to occur in the next [next what?] based on current levels of pollution are said to be 'in the pipeline. "')

I Lenton, et aI, supra note [ ], at 1792 ("The greatest threats are tipping the Arctic sea-ice and the Greenland ice sheet, and at least five other elements could surprise us by exhibiting a nearby tipping point.")

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12 Lenton, et ai, supra note [ ], at 1786. 13 David Spratt, The Big Melt: Lessonsfrom the Arctic summer 0/2007, 6 October 2007, updated 5 November 2007,3. 14 Lenton, et ai, supra note [ ], at 1788 ("As sea-ice melts, it exposes a much darker ocean surface, which absorbs more radiation - amplifying the warming.") 15 James Hansen, Scientific reticence and sea level rise, Environ. Res. Lett. 2 (2007) ("Ice sheet disintegration, unlike ice sheet growth, is a wet process that can proceed rapidly. Multiple positive feedbacks accelerate the process once it is underway. These feedbacks occur on and under the ice sheets and in the nearby oceans. A key feedback on the ice sheets is the 'albedo flip' that occurs when snow and ice begin to melt. Snow-covered ice reflects back to space most of the sunlight striking it. However, as warming air causes melting on the surface, the darker wet ice absorbs much more solar energy. Most of the resulting melt water burrows through the ice sheet, lubricates its base, and thus speeds the discharge of icebergs to the ocean.") available at http://www.iop.orglEJ/articleI1748-9326/2/2/024002/erl7 2 024002.pdf?reguest-id=2055b 1 cb-b869-4ctb-b257-3a 1 e46393fd2 accessed on 12 September 2008; see also James Hansen, Makiko Sato, Pushker Kharecha, Gary Russell, David W. Lea, Mark Siddall, Climate change and trace gases, Phil. Trans. R. Soc. A (2007) 365, 1925-1954, 1925 available at http://pubs.giss.nasa.gov/docs/2007/2007 Hansen etal 2.pdf accessed on 15 September 2008. 16 James Hansen & Larissa Nazarenko, Soot Climate Forcing Via Snow and Ice Albedos, 101 PROC. OF THE NAT'LACAD. OF SCI. 428 (13 January 2004). 17 University of Alaska, A classification of sea ice using its albedo, available at http://www.gi.alaska.edu/~eicken/heteach/GEOS615icenom/albedo/albedo%20classification.htm#dirt

accessed on 08 September 2008. 18 IPCC, "Global climate projections", Climate Change 2007: The Physical Sciences Basis, 776 ("Arctic sea ice is responding sensitively to global warming. While changes in winter sea ice are moderate, late summer sea ice is projected to disappear almost completely towards the end of the 21 sl century.") 19Lenton, et ai, supra note [ ], at 1788 ("Transient warming is generally greater toward the poles and greater on the land than in the ocean."); see also, The University of Melbourne for the Climate Institute, Climate Adaptation Science and Policy Initiative, Evidence 0/ Accelerated Climate Change, November 2007,5 ("The rate of warming in [the Arctic Peninsula] is approximately 0.5 C per decade, compared to the global rate of about 0.2 C per decade.") see also Lemke, P., J. Ren, R.B. Alley, I. Allison, J. Carrasco, G. Flato, Y. Fujii, G. Kaser, P. Mote, R.H. Thomas and T. Zhang, 2007: Observations: Changes in Snow, Ice and Frozen Ground. In: Climate Change 2007: The Physical Science Basis. Contribution o/Working Group I to the Fourth Assessment Report o/the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 339 ("Recent decreases in ice mass are correlated with rising surface air temperatures. This is especially true for the region north of 65°N, where temperatures have increased by about twice the global average from 1965 to 2005."). 20 Spratt, supra note [ ], at 3 ("The IPCC's four-year schedule for producing reports requires a deadline for scientific papers that is often more than two years prior to the report's final release. What happens ifthere is significant new evidence or events that dramatically change [sic] our understanding of climate science in the gap between the science reporting deadline and publication? They don't get a mention, so the IPCC report is out of date before it hits the presses, and in the rapidly changing world of global warming that is a serious problem because it is widely viewed as the climate change Bible.") 21 Spratt, supra note [ ], at 6-7 ("The Arctic sea ice minimum on 16 September was 4.13 million square kilometers, compared to the previous record low of 5.32 million square kilometers in 2005, representing a precipitous decline of22 percent in 2 years.") 22 National Snow and Ice Data Center, "Arctic Sea Ice News and Analysis" biweekly updates available at http://nsidc.org/arcticseaicenews/ accessed on September 4, 2008 ("Following a record rate of ice loss through the month of August, Arctic sea ice extent already stands as the second-lowest on record, further reinforcing conclusions that the Arctic sea ice cover is in a long-term state of decline. With approximately two weeks left in the melt season, the possibility of setting a new record annual minimum in September remains open .... Arctic sea ice extent on September 3 was 4.85 million square kilometers (1.87 million square miles), a decline of2.47 million square kilometers (950,000 square miles) since the beginning of August. Extent is now within 370,000 square kilometers (140,000 square miles) oflast year's value on the

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same date and is 2.08 million square kilometers (800,000 square miles) below the 1979 to 2000 average."); see also Lenton, et ai, supra note [ ], at 1788, Table 1. 23 Spratt, supra note [ ], at 4. 24 Spratt, supra note [ ], at 7 ("Dr Wieslaw Maslowski of the Naval Postgraduate School in California, whose research focuses on modeling-the processes of Arctic sea ice loss, projects a blue Arctic Ocean free of sea ice by the summer of2013 [internal citation omitted], the main reason being that the modeled thickness and volume appear to be decreasing at a much faster rate than the satellite derived ice extent [internal citation omitted]. Maslowski's work suggests the sea ice is significantly being thinned by the effect of the warming seas beneath, not just higher air temperatures.") 25 WWF, "Lowest ever sea ice in the Arctic" available at http://www.panda.orglnews facts/newsroom/news/index.cfm?uNewsID=145182 accessed on 15 September 2008. 26 See e.g., UN University, Institute of Advanced Studies, Japan, Press Release, Experts Consider Needfor New Rules to Govern World's Fragile Polar Regions (7 September 2008) (Iceland conference 7-9 September 2008 exploring need for better international approach to control polar activities, including resource exploration, as summer ice retreats.) available at http://www.ias.unu.edulsub page.aspx?catID=35&ddIID=708 accessed on 12 September 2008; see also New Scientist, Race to claim the Arctic (22 December 2007) available at http://environment.newscientist.com/channel/earth/mgI9626355.500-news-review-2007-race-to-claim-thearctic.htm accessed on 12 September 2008. 27 Spratt, supra note [ ], at 7. 28 Spratt, supra note [ ], at 9. 29 Lenton, et ai, supra note [ ], at 1789. 30 Lenton, et ai, supra note [ ], at 1789 ("[I]n deglaciation, warming at the periphery lowers ice altitude, increasing the surface temperature and causing a positive feedback that is expected to exhibit a critical threshold beyond which there is ongoing net mass loss and the GIS shrinks radically or eventually disappears.") 31 Lenton, et ai, supra note [ ], at 1788 (" ... surging of outlet glaciers ... may be contributed to by the intrusion of warming ocean waters"); see also Spratt, supra note [], at 8-9 (" ... this accelerated melting 'is caused by meltwater penetrating crevasses and lubricating the glacier's flow ... the ice is in effect sliding into the ocean on rivers of water,' an effect not included in the models of the effect of global warming ... ") 32 Spratt, supra note [ ], at 8. 33 Spratt, supra note [ ], at 8; Lenton, et ai, supra note [ ], at 1789. 34 Spratt, supra note [ ], at 9; Lenton, et ai, supra note [ ], at 1789. 35 Lenton, et ai, supra note [ ], at 1789. 36 Spratt, supra note [], at 9; Lenton, et ai, supra note [], at 1789. 37 Spratt, supra note [ ], at 10. 38 Lenton, et ai, supra note [ ], at 1789. 39 Lenton, et ai, supra note [ ], at 1788, Table 1. 40 Spratt, supra note [ ], at 8 ("Rising Arctic regional temperatures resulting from sea ice loss and albedo effect (white, reflective ice replaced by dark, heat-absorbing sea) are already at 'the threshold beyond which glaciologists think that the (Greenland) ice sheet may be doomed. '''); see also Spratt, supra note [ ], at 10 ("Global warming seems to be pushing the vast reservoirs of ice on Greenland and Antarctica toward a significant, long-term meltdown, and the world may have as little as a decade to take the steps to avoid this scenario.") 41 Lenton, et ai, supra note [ ], at 1789. 42 Lenton, et ai, supra note [ ], at 1789. 43 Spratt, supra note [ ], at 13. 44 Lenton, et ai, supra note [ ], at 1789. 45 Spratt, supra note [ ], at 13. 46 Lenton, et ai, supra note [ ], at 1789. 47 The University of Melbourne, supra note [], at 5; see also [until I can find a more scholarly source] National Snow and Ice Data Center, "Larsen B Ice Shelf Collapses in Antarctica", 18 March 2002, updated 212 March 2002 ("Ted Scambos, a researcher with the National Snow and Ice Data Center (NSIDC) at University of Colorado, and a team of collaborating investigators, developed a theory of how the ice

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disintegrates. The theory is based on the presence of ponded melt water on the surface in late summer as the climate has warmed in the area. Meltwater acts to enhance fracturing of the shelf by filling smaller cracks and forcing them through the thickness of the ice due to the weight of the water ... satellite images have provided substantial observational proof that it is in fact the main process responsible for the Peninsula shelf disintegrations.") 48 Lenton, et ai, supra note [ ], at 1789. 49 Lenton, et ai, supra note [ ], at 1789. 50 Lenton, et ai, supra note [ ], at 1788, Table I. 51 United Nations Environment Programme (UNEP) and World Glacier Monitoring Service (WGMS) [hereinafter UNEP and WGMS Report], "Global glacier changes: facts and figures" [03 September 2008], 11. 52 UNEP and WGMS Report, supra note [ ], at 11. 53 UNEP and WGMS Report, supra note [ ], at 11. 54 V. Ramanathan and G. Carmichael, Global and regional climate changes due to black carbon, 1 NATURE GEOSCIENCE 224 (23 March 2008). 55 Ramanathan and Carmichael, supra note [ ], at 224. 56 Lester R. Brown, Melting Mountain Glaciers Will Shrink Grain Harvests in China and India, PLAN B UPDATE, Earth Policy Institute (20 March 2008), available at http://www.earthpolicy.org/Updates/2008/Update71.htm ("Melting Himalayan glaciers will soon reduce water supply for major Chinese and Indian rivers (Ganges, Yellow River, Yangtze River) that irrigate rice and wheat crops that feed hundreds of millions and "could lead to politically unmanageable food shortages."). 57 Claudia Delpero, "Melting Glaciers on the Tibetan Plateau", 10 July 2007 available at http://www.panda.org/news facts/newsroomiindex.cfm?uNewsID=1 08360 accessed on 15 September 2008. 58 David Spratt and Philip Sutton, Target practice: Where should we aim to avoid dangerous climate change?, November 2007,8. 59 Spratt and Sutton, supra at note [ ], at 8. 60 Plataforma SINC "Glaciers In The Pyrenees Will Disappear In Less Than 50 Years, Study Finds", ScienceDaily, 6 September 2008 available at http://www.sciencedaily.com/releases/2008/09/080905164328.htm accessed on 15 September 2008. 61 Spratt and Sutton, supra at note [ ], at 8. 62 UNEP and WGMS Report, supra note [], at 43. 63 Spratt and Sutton, supra at note [ ], at 8. 64 Spratt and Sutton, supra at note [ ], at 8. 65 The Sierra Nevada Alliance, "Background on Climate Change and Sierra Water" available at http://www .sierranevadaalliance.org/programs/program.shtml?type=pgm01 accessed on 12 August 2008; see also Kerri L. Timmer, Troubled Water of the Sierra, The Sierra Nevada Alliance, 2003, 25-26. 66 Lenton, et ai, supra note [ ], at 1789. 67 Spratt, supra note [ ], at [need to find quote]. 68 [In Day After, from Woods Hole?] 69 Lenton, et ai, supra note [ ], at 1789. 70 Lenton, et ai, supra note [ ], at 1789. 71 ACC: Inevitable Surprises, supra note [], at []; Lenton, et ai, supra note [], at 1789. 72 Peter Schwartz and Doug Randall, An Abrupt Climate Change Scenario and Its Implications for United States National Security, OCtober 2003, 18-19. ("The remarkable feature of the Younger Dryas event was that it happened in a series of decadal drops of around 5 degrees, and then the cold, dry weather persisted for over 1,000 years. While this event had an enormous effect on the ocean and land surrounding Europe (causing icebergs to be found as far south as the coast of Portugal), its impact would be more severe today - in our densely populated society.") 73 !d.; see also Peter Read and Jonathan Lermit, Bio-Energy with Carbon Storage (BECS): a Sequential Decision Approach to the threat of Abrupt Climate Change, 2 ("Abrupt climate change is [within this article] taken to be a shift in climate regime that may have only minor impacts, to which adaptation is acceptable, or that may be more serious, even catastrophic. Of the latter variety are shifts into and out of the major reallocations of surface water that characterize ice ages and ice free periods (of which the latter have

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not occurred since half a million years ago, when the present ice cps formed, and the former many times during that period, with the onset of some glaciation episodes having taken no more than a few decades).") 74 Lenton, et aI, supra note [ ], at 1790. 75 Lenton, et aI, supra note [ ], at 1788, Table 1, 1790. 76 Spratt and Sutton, supra at note [ ], at 8. 77 Spratt and Sutton, supra at note [ ], at 9; Lenton, et aI, supra note [ ], at 1790. 78 Spratt and Sutton, supra at note [ ], at 9. 79 B. N. Goswami, V. Venugopal, D. Sengupta, M. S. Madhusoodanan, Prince K. Xavier, Increasing Trend of Extreme Rain Events Over India in a Warming Environment, 314 SCIENCE 442, 1 December 2006, 1442. 80 Lenton, et aI, supra note [ ], at 1790; see also Goswami, et aI, supra note [ ], at 1443 ("However, interannual changes in moisture content over [Central India (CI)] can be influenced by regional-scale land surface processes as well as by atmospheric teleconnections associated with remote SST such as the El Nino and Southern Oscillation (ENSO). Although El Nino events are generally associated with positive SST anomaly over the tropical 10, they lead to drying of the atmosphere over CI through large-scale subsidence.") 81 This increasing frequency and intensity of severe rains has been accompanied by a decreasing frequency of moderate rain events, which is another problem. Goswami, et aI, supra note [], at []. 82 Meehl, G.A., T.F. Stocker, W.D. Collins, P. Friedlingstein, A.T. Gaye, J.M. Gregory, A. Kitoh, R. Knutti, J.M. Murphy, A. Noda, S.C.B. Raper, I.G. Watterson, A.J. Weaver and Z.-C. Zhao, 2007: Global Climate Projections. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, KB. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 778. 83 Lenton, et aI, supra note [ ], at 1790. 84 Meehl, et aI, supra note [ ], at 778. 85 Lenton, et aI, supra note [ ], at 1790. 86 Chris Funk, Michael D. Dettinger, Joel C. Michaelsen, James P. Verdin, Molly E. Brown, Mathew Barlow and Andrew Hoell, Warming of the Indian Ocean threatens eastern and southern African food security but could be mitigated by agricultural development, 105 PROC. OF THE NAT'L ACAD. OF SCI. 32, 11084 (12 August 2008). 87 Christensen, J.H., B. Hewitson, A. Busuioc, A. Chen, X. Gao, I. Held, R. Jones, R.K Kolli, W.-T. Kwon, R. Laprise, V. Magana Rueda, L. Mearns, C.G. Menendez, J. Raisanen, A. Rinke, A. Sarr and P. Whetton, 2007: Regional Climate Projections. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, KB. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 866. 88 Christensen, supra note [ ], at 866. 89 Lenton, et aI, supra note [ ], at 1790. 90 Lenton, et aI, supra note [ ], at 1790. 91 Claussen, V., Brovkin, V., Ganoposki, A., 2002. Africa: Greening of the Sahara, in Challenges ofa Changing Earth, ed. by W. Steffen et aI., Proceedings of the Global Change Open Science Conference, Amsterdam, The Netherlands, 10-13 July 2001. Springer-Verlag Berlin Heidelberg,p. 125 - 128. 92 Funk, et aI, supra note [ ], at 11084. 93 Funk, et aI, supra note [ ], at 11084. 94 Funk, et aI, supra note [ ], at 11081 ("Tracing moisture deficits upstream to an anthropogenically warming Indian Ocean leads us to conclude that further rainfall declines are likely. We present analyses suggesting that warming in the central Indian Ocean disrupts onshore moisture transports, reducing continental rainfall. Thus, late 20th century anthropogenic Indian Ocean warming has probably already produced societally dangerous climate change by creating drought and social disruption in some of the world's most fragile food economies ... Persistence of current tendencies may result in a 50% increase of undernourished people by 2030. On the other hand, modest increases in per-capita agricultural productivity could more than offset the observed precipitation declines.") 95 Lenton, et aI, supra note [ ], at 1790 ("Dieback of the Amazon rainforest has been predicted to occur under ~ 3_4 0 C global warming ... "); see also Spratt and Sutton, supra note [ ], at 9 ("Between 20 C and 30

C, the Amazon rainforest...may turn to savannah ... ")

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96 Lenton, et aI, supra note [ ], at 1790. 97 Spratt and Sutton, supra note [ ], at 9; see also Easterling, W.E., P.K Aggarwal, P. Batima, KM. Brander, L. Erda, S.M. Howden, A. Kirilenko, J. Morton, J.-F. Soussana, J. Schmidhuber and F.N. Tubiello, 2007: Food, fibre and forest products. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution a/Working Group II to the Fourth Assessment Report a/the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 273-313, 281. ("Simulations show that during the 2001 ENSO period approximately one-third of Amazon forests became susceptible to fire.") 98 Spratt and Sutton, supra note [ ], at 8. 99 Lenton, et aI, supra note [ ], at 1790; see also Easterling, et aI, supra note [ ], at 281. 100 Lenton, et aI, supra note [ ], at 1791. 101 Lenton, et aI, supra note [ ], at 1791. 102 Spratt, supra note [ ], at 16 ("As the Arctic warms, permafrost in the boreal forests and further north in the Arctic tundra is now starting to melt, triggering the release of methane, a greenhouse gas twenty-five times more powerful than C02, from thick layers of thawing peat. With less than one degree of warming, Arctic ground frozen by permafrost for 3000 years is melting, producing thermokarst (land surface that forms as ice-rich permafrost melts) that potentially can affect 10-30% of arctic lowland landscapes and severely alter tundra ecosystems even under scenarios of modest climate warming [internal citation omitted]. As permafrost thaws and lakes form, microbes convert the soils' organic matter into methane, which bubbles through the surface water into the atmosphere; where permafrost decay is a dry process, C02 is released.") 103 Lenton, et aI, supra note [ ], at 1791. 104 Lenton, et aI, supra note [ ], at 1788, Table 1. lOS Lenton, et aI, supra note [ ], at 1788, Table 1. 106 Spratt, supra note [ ], at 13. 107 Spratt, supra note [ ], at 13, quoting Nicholas Stern, "Executive Summary", Stem Review on the Economics of Climate Change, October 2006 [ check link http://www.hmtreasury.gov.uk/independent reviews economics climate change/sternreview summary.cfm]. 108 Spratt, supra note [ ], at 13 109 Spratt, supra note [ ], at 13. 110 Mimura, N., L. Nurse, R.F. McLean, J. Agard, L. Briguglio, P. Lefale, R. Payet and G. Sem, 2007: Small islands. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution a/Working Group II to the Fourth Assessment Report a/the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, PJ. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 687-716, 689. III Lester R. Brown, Melting Mountain Glaciers Will Shrink Grain Harvests in China and India, PLAN B UPDATE, Earth Policy Institute (20 March 2008), available at http://www.earthpolicy.org/Updates/2008/Update71.htm ("Melting Himalayan glaciers will soon reduce water supply for major Chinese and Indian rivers (Ganges, Yellow River, Yangtze River) that irrigate rice and wheat crops that feed hundreds of millions and "could lead to politically unmanageable food shortages."); see also WWF Nepal Program An Overview of Glaciers, Glacier Retreat, and Subsequent Impacts in Nepal, India and China (2005), 2 available at http://assets.panda.org/downloads/himalayaglaciersreport2005.pdf accessed on 15 September 2008. 112 The Sierra Nevada Alliance, "Background on Climate Change and Sierra Water" available at http://www.sierranevadaalliance.org/programs/program.shtml?type=pgmOI accessed on 12 August 2008; see also Kerri L. Timmer, Troubled Water a/the Sierra, The Sierra Nevada Alliance, 2003, 25-26. 113 Spratt, supra note [ ], at 8. 114 WWF Nepal Program, supra note []. lIS Spratt, supra note [ ], at 8. 116 Funk, et aI, supra note [ ], at 11081. 117 Spratt, supra note [], at 8. 118 James Hansen, Makiko Sato, Pushker Kharecha, Gary Russell, David W. Lea, Mark Siddall, Climate change and trace gases, Phil. Trans. R. Soc. A (2007) 365, 1925-1954, 1925.

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119 David Archer, "Methane hydrates and anthropogenic climate change", 16; see also The University of Melbourne, supra note [ ], at 7. 120 Spratt, supra note [ ], at 16. 121 Jamais Cascio, "Methane Trigger fro Geo & Bioengineering" available at http://www.openthefuture.com/2008/08/methanetriggerforgeobioen.htmlaccessed on 06 September 2008 [ replace with International Siberian Shelf Study 2008 (lSSS-08) when published later this year] 122 Archer, supra note [ ], at 16. 123 Archer, supra note [ ], at 16. 124 Archer, supra note [ ], at 1. 125 Mau, S., D. L. Valentine, 1. F. Clark, 1. Reed, R. Camilli, and L. Washburn (2007), Dissolved methane distributions and air-sea flux in the plume of a massive seep field, Coal Oil Point, California. Geophys. Res. Lett., 34 (22) L22603, doi: 10.1 029/2007GL031344. [I need access to this article!] 126 Schwartz and Randall, supra note [ ], at 1-2. 127 Schwartz and Randall, supra note [ ], at 2, 6. 128 Schwartz and Randall, supra note [ ], at 2. 129 Schwartz and Randall, supra note [ ], at 2. 130 Schwartz and Randall, supra note [], at 2,14. 131 Spratt, supra note [ ], at 3. 132 Laurence Caramel and Stephane Foucart, "Rajendra Pachauri: We Have Seven Years Left to Reverse the C02 Emissions Curve" Le Monde, 07 July 2008. 133 Spratt and Sutton, supra note [ ], at 5 quoting Harvey, L. (2007) "Dangerous anthropogenic interference, dangerous climate change, and harmful climactic change: non-trivial distinctions with significant policy implications", Climactic Change 82(1-2):1-25.

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Documents

Tipping Points that Could Lead to Abrupt Climate Change 87.pdfis a point at which the climate, without additional forcing, undergoes rapid changes that are practically uncontrollable.8