“There's a wealth of real possibilities for change to a more sustainable and more human course.” – Bill McKibben, billmckibben.com on Plan B.
Chapter 4. Rising Temperatures and Rising Seas: Melting Ice and Rising Seas
In its landmark third report, released in early 2001, the IPCC projected that sea level would rise during this century by 0.09–0.88 meters (4–35 inches) as a result of thermal expansion and ice melting. Numerous new studies during the four years since then indicate that the earth’s ice cover is melting even faster than IPCC scientists projected. 34
A 2002 study by two scientists from the University of Colorado’s Institute of Arctic and Alpine Research showed that the melting of large glaciers on the west coast of Alaska and in northern Canada is accelerating. Earlier data had indicated that this melting was raising sea level by 0.14 millimeters per year, but new data for the 1990s show that the more rapid melting is now raising sea level by 0.32 millimeters a year—more than twice as fast. 35
This study is reinforced by a U.S. Geological Survey (USGS) study that indicated glaciers are now shrinking in all 11 of Alaska’s glaciated mountain ranges. An earlier USGS study reported that the number of glaciers in Glacier National Park in the United States had dwindled from 150 in 1850 to fewer than 50 today. The remaining glaciers are projected to disappear within 30 years, leaving future generations of visitors to puzzle over the park’s name. 36
Another team of USGS scientists, which used satellite data to measure changes in the area covered by glaciers worldwide, described an accelerated melting of glaciers in several mountainous regions, including the South American Andes, the Swiss Alps, and the French and Spanish Pyrenees. 37
The melting of glaciers is gaining momentum throughout the Andes. Glaciologist Lonnie Thompson of Ohio State University reports that the Qori Kalis glacier, on the west side of the Quelccaya ice cap in the Peruvian Andes, shrank three times as fast each year from 1998 to 2000 as it did between 1995 and 1998. And the earlier rate, in turn, was nearly double the annual rate of retreat from 1993 to 1995. Thompson projects that the Quelccaya ice cap will disappear entirely between 2010 and 2020. In nearby Ecuador, the Antisana glacier, which supplies half of the water for Quito, has retreated nearly 100 meters in the last eight years. 38
Bernard Francou, research director for the French government’s Institute of Research and Development, believes that 80 percent of South American glaciers will disappear within the next 15 years. For countries like Bolivia, Peru, and Ecuador, which rely on glaciers for water for household and irrigation use, this is not good news. 39
The European Alps are also suffering a meltdown. Scientists at Zurich University report that glaciers in Switzerland shrank by 1 percent from 1973 to 1985 but that the area covered shrank 18 percent between 1985 and 2000. They observed that “the changes could also impact tourism, a crucial pillar of the Swiss economy, as the country’s scenic glacial valleys become barren and rocky.” As the glaciers disappear and the snowline retreats upward, the winter ski season will shrink. 40
Lonnie Thompson’s studies of Kilimanjaro show that between 1989 and 2000, Africa’s tallest mountain lost 33 percent of its ice field. He projected that its snowcap could disappear entirely by 2015. In March 2005, the Guardian in London reported: “Africa’s tallest mountain, with its white peak, is one of the most instantly recognizable sites in the world. But as this aerial photograph shows, Kilimanjaro’s trademark snowy cap, at 5,895 meters (19,340 feet), is now all but gone—15 years before scientists predicted it.” 41
The vast snow/ice mass in the Himalayas is also retreating. The Union Internationale des Associations d’Alpinisme reports that the glacier that ended at the base camp from which Edmund Hillary and Tenzing Norgay launched their history-making ascent of Everest in 1953 has retreated about 5 kilometers (3 miles). Geologist Jeffrey Kargel, who studies the Himalayas, is not surprised by this. “That fits in with the general picture of what’s happening in Nepal, India, Bhutan and, to a smaller extent, Tibet,” he says. 42
A recently completed study by a team of more than 50 U.S. and Chinese scientists over 26 years measured the accelerated melting of the glaciers in Western China. The study reported that the volume of China’s 46,298 glaciers has shrunk by 5.5 percent in the past 24 years. The melting of glaciers in this region, as in most other areas of the world, has accelerated sharply since the early 1990s. 43
Yao Tandong, a leading Chinese glaciologist and contributor to the study, predicted that two thirds of China’s glaciers could be gone by 2060. Melting of the vast Himalayan ice fields, which contain more ice than any region outside of the poles, could dramatically raise sea level. Yao Tandong summarized the situation: “The full-scale glacier shrinkage in the plateau region will eventually lead to an ecological catastrophe.” 44
Another recent study, Impacts of a Warming Arctic, concluded that the Arctic is warming almost twice as fast as the rest of the planet. Conducted by the Arctic Climate Impact Assessment (ACIA) team, an international group of 300 scientists, the study found that in the regions surrounding the Arctic, including Alaska, western Canada, and Eastern Russia, winter temperatures have already climbed by 3–4 degrees Celsius (4–7 degrees Fahrenheit) over the last half-century. Robert Corell, chair of ACIA observes, “The impacts of global warming are affecting people now in the Arctic.” This region, he says, “is experiencing some of the most rapid and severe climate change on Earth.” 45
In testimony before the U.S. Senate Commerce Committee, Sheila Watt-Cloutier, an Inuit speaking on behalf of the 155,000 Inuits who live in Alaska, Canada, Greenland, and the Russian Federation, described the Inuits’ struggle to survive in the fast-changing Arctic climate as “a snapshot of what is happening to the planet.” She called the warming of the Arctic “a defining event in the history of this planet.” And she went on to say “the Earth is literally melting.” 46
The ACIA report described how the retreat of the sea ice has “devastating consequences for polar bears” whose very survival may be at stake. Also threatened are the ice-living seals, a basic food source for the Inuits. 47
Higher Arctic temperatures are also thawing what had been perpetually frozen soils of the region. As the tundra thaws, it destabilizes and damages buildings, pipelines, and roads. The melting of the tundra has effects far beyond local structural problems. A report in Science says, “No one knows exactly how much carbon is locked up in boreal and alpine permafrost, but estimates range from 350 to 450 gigatons [billion tons]—perhaps a quarter to a third of all soil carbon. The big question is what will happen if even a fraction of this massive carbon store is liberated.” This compares with the 7 billion tons of carbon that is emitted from burning fossil fuels each year. 48
The scientists chronicling the warming of the Arctic are perhaps most concerned about the effect on Greenland. If all the ice in the Arctic Sea melts, it will not affect sea level because that ice is already in the water. But if the warming of the Arctic melts the Greenland ice sheet, which is a mile and a half thick in some places, sea level would rise by 7 meters (23 feet). Such a melting of the Greenland ice sheet would be measured in centuries, not years. Nonetheless, recent maps show rapid melting around the ice sheet’s outer edges, particularly on the eastern coast. 49
Scientists are concerned about the melting of the Greenland ice sheet not only because of its obvious effect on sea level, but also because it might disrupt ocean circulation, particularly the flow of the Gulf Stream. Under current conditions, the Gulf Stream that brings warm surface water northward from the South Atlantic supports Western Europe’s mild climate. As the high-salinity warm water moves northward, it cools as a result of heat loss and evaporation, becoming more dense and salty. This eventually causes it to sink and then flow southward as deep water. An influx of fresh water from melting of the Greenland ice sheet or of Arctic sea ice could disrupt this circulation pattern, resulting in somewhat lower temperatures in the northeastern United States and eastern Canada and a sharp temperature drop in Europe. Historical evidence suggests that such shifts have sometimes come quickly—in a matter of years or decades. 50
As the Arctic sea ice melts, it opens the possibility of using the Arctic Sea as a shipping route between the Atlantic and Pacific Oceans. The search for the Northwest Passage, a dream of early explorers who otherwise had to sail around the Cape of Good Hope, could become a nightmare for our early twenty-first century society. Shipping companies are already looking at potential shortcuts. The trip from Europe to Asia via the Panama Canal typically covers some 12,600 nautical miles, according to an article in Canada’s Globe and Mail, while the trip via the Northwest Passage would be shortened to 7,900 nautical miles. The risk is that the environmental damage from any accidents, such as an oil spill in the Arctic Sea, could last for decades if not longer in this frigid environment. 51
At the other end of the earth, the 2-kilometer thick Antarctic ice sheet covers a continent about twice the size of Australia and contains 70 percent of the world’s fresh water. Ice shelves that extend from the continent into the surrounding seas are beginning to break up at an alarming pace. 52
The ice shelves surrounding Antarctica are formed by the flow of glaciers off the continent to lower levels in the surrounding sea. This flow of ice, fed by the continuous formation of new ice on land and culminating in the breakup of the shelves on the outer fringe and the calving of icebergs, is not new. What is new is the pace of this process. When Larsen A, a huge ice shelf on the east coast of the Antarctic Peninsula, broke up in 1995, it was a signal that all was not well in the region. Then in 2000, a huge iceberg nearly the size of Connecticut—11,000 square kilometers, or 4,250 square miles—broke off the Ross Ice Shelf. 53
After Larsen A broke up, it was only a matter of time, given the rise in temperature in the region, before Larsen B would do the same. In November 2001, an alert went out to the
scientific community from a researcher at the Instituto Antártico Argentino, who noted the unusually warm spring temperature and the 20-percent acceleration in the flow of the ice shelf. So when the northern part of the Larsen B ice shelf collapsed into the sea in March 2002, it was not a total surprise. At about the same time, a huge chunk of ice broke off the Thwaite Glacier. Covering 5,500 square kilometers, this iceberg was the size of Rhode Island. 54
Even veteran ice watchers are amazed at how quickly the disintegration is occurring. “The speed of it is staggering,” said Dr. David Vaughan, a glaciologist at the British Antarctic Survey, which has been monitoring the Larsen Ice Shelf closely. Along the Antarctic Peninsula, in the vicinity of the Larsen Ice Shelf, the average temperature has risen 2.5 degrees Celsius over the last five decades. Higher temperatures lead to ice melting on the surface of the ice shelves. Scientists theorize that as the melted water on the surface penetrates fractures, it weakens the ice, making it vulnerable to further fracturing. 55
When ice shelves already in the water break off from the continental ice mass, this does not have much direct effect on sea level per se. But without the ice shelves to impede the flow of glacial ice, typically moving 400–900 meters a year, the flow of ice from the continent could accelerate, leading to a thinning of the ice sheet on the edges of the Antarctic continent. If this were to happen, sea level would rise. Dr. Neal Young of the Antarctic Cooperative Research Centre at the University of Tasmania in Australia notes that after Larsen A broke off, the upstream rate of glacial flow at least doubled. 56
The accelerated melting of ice, which is consistent with the accelerating rise in temperature that has occurred since 1980, is of great concern in low-lying regions of coastal countries and low-lying island countries. Perhaps the most easily measured effect of rising sea level is the inundation of coastal areas. Donald F. Boesch, with the University of Maryland’s Center for Environmental Sciences, estimates that for each 1-meter rise in sea level, the shoreline will retreat by an average 1,500 meters, or nearly a mile. 57
In 2000, the World Bank published a map showing that a 1-meter rise in sea level would inundate half of Bangladesh’s riceland. With a rise in sea level of up to 1 meter forecast for this century, tens of millions of Bangladeshis would be forced to migrate. In a country with 142 million people—already one of the most densely populated on earth—this would be a traumatic experience. Rice-growing river floodplains in other Asian countries would also be affected, including India, Thailand, Viet Nam, Indonesia, and China. With a 1-meter rise in sea level, more than a third of Shanghai, a city of 13 million people, would be under water. 58
Such a rise would cost the United States 36,000 square kilometers (14,000 square miles) of land, most of it in the middle Atlantic and Mississippi Gulf states. With a 50-year storm surge, large portions of Lower Manhattan and the National Mall in the center of Washington, D.C., would be flooded with seawater. 59
While public attention focuses on the effect of ice melting on sea level rise, the thermal expansion of the oceans as a result of rising temperature is also raising sea level. At present, scientists estimate the relative contributions of ice melting and thermal expansion to sea level rise to be about the same. Together, the two are raising sea level at a measurable rate. It has become an indicator to watch—a trend that could force a human migration of unimaginable dimensions. It also raises questions about responsibility to future generations that humanity has never before faced. 60
34. IPCC, op. cit. note 11.
35. University of Colorado at Boulder, “Global Sea Levels Likely to Rise Higher in 21st Century than Previous Predictions,” press release (Boulder, CO: 16 February 2002).
36. “Alaska Examines Impacts of Global Warming,” National Geographic News, 21 December 2001; Myrna H. P. Hall and Daniel B. Fagre, “Modeled Climate-Induced Glacier Change in Glacier National Park, 1850–2100,” BioScience, February 2003, pp. 131–40.
37. American Institute of Physics, “New Research Shows Mountain Glaciers Shrinking Worldwide,” press release (Boston: 30 May 2001).
38. Thompson, op. cit. note 33; Eric Hansen, “Hot Peaks,” OnEarth, fall 2002, p. 8.
39. Hansen, op. cit. note 38.
40. Paul et al., op. cit. note 11; Ceri Radford, “Melting Swiss Glaciers Threaten Alps,” Reuters, 16 November 2004.
41. Thompson, op. cit. note 11; “The Peak of Mt Kilimanjaro As It Has Not Been Seen for 11,000 Years,” The Guardian (London), 14 March 2005.
42. Kargel quoted in Hansen, op. cit. note 38.
43. Jonathan Watts, “Highest Icefields Will Not Last 100 Years, Study Finds: China’s Glacier Research Warns of Deserts and Floods Due to Warming,” The Guardian (London), 24 September 2004; “China Warns of ‘Ecological Catastrophe’ from Tibet’s Melting Glaciers,” Agence France-Presse, 5 October 2004; “Glacier Study Reveals Chilling Prediction,” China Daily, 23 September 2004.
44. Watts, op. cit. note 43; “China Warns of ‘Ecological Catastrophe’ from Tibet’s Melting Glaciers,” op. cit. note 43; “Glacier Study Reveals Chilling Prediction,” op. cit note 43.
45. ACIA op. cit. note 11; ACIA Web site, www.acia.uaf.edu, updated 13 July 2005; “Rapid Arctic Warming Brings Sea Level Rise, Extinctions,” Environment News Service, 8 November 2004.
46. J. R. Pegg, “The Earth is Melting, Arctic Native Leader Warns,” Environment News Service, 16 September 2004.
47. ACIA, op. cit. note 11.
48. Erik Stokstad, “Defrosting the Carbon Freezer of the North,” Science, vol. 304 (11 June 2004), pp. 1618–20; carbon emissions in G. Marland, T. A. Boden, and R. J. Andres, “Global, Regional, and National CO 2 Emissions,” in Oak Ridge National Laboratory, op. cit. note 2.
49. R. Warrick et al., “Changes in Sea-Level,” in J.T. Houghton et al., eds., Climate Change, 1995: The Science of Climate Change (Cambridge, U.K.: Cambridge University Press, 1995), pp. 359–405, cited in Dorthe Dahl-Jensen, “The Greenland Ice Sheet Reacts,” Science, vol. 289 (21 July 2000), pp. 404–05.
50. IPCC, Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change (New York: Cambridge University Press, 2001), pp. 948–51; Committee of Abrupt Climate Change, Abrupt Climate Change: Inevitable Surprises (Washington, DC: National Research Council, 2002).
51. Joe Friesen, “Arctic Melt May Open Up Northwest Passage: Portal Could Cut Nearly 5,000 Nautical Miles From Asia-Europe Trip Via Panama Canal,” Globe and Mail (Toronto), 9 November 2004.
52. U.S. Department of Energy, Energy Information Administration, “Antarctica: Fact Sheet,” at www.eia.doe.gov/emeu/cabs/antarctica.html, September 2000.
53. Andrew Shepherd, “Larsen Ice Sheet Has Progressively Thinned,” Science, vol. 302 (31 October 2003), pp. 856–59; “Breakaway Bergs Disrupt Antarctic Ecosystem,” Environment News Service, 9 May 2002; “Giant Antarctic Ice Shelves Shatter and Break Away,” Environment News Service, 19 March 2002.
54. NSIDC, “Antarctic Ice Shelf Collapses,” at nsidc.org/iceshelves/larsenb2002, 19 March 2002; “Breakaway Bergs Disrupt Antarctic Ecosystem,” op. cit. note 53; “Giant Antarctic Ice Shelves Shatter and Break Away,” op. cit. note 53.
55. NSIDC, op. cit. note 54; “Breakaway Bergs Disrupt Antarctic Ecosystem,” op. cit. note 53; “Giant Antarctic Ice Shelves Shatter and Break Away,” op. cit. note 53; Vaughan quoted in Andrew Revkin, “Large Ice Shelf in Antarctica Disintegrates at Great Speed,” New York Times, 20 March 2002.
56. Michael Byrnes, “New Antarctic Iceberg Split No Threat,” Reuters, 20 May 2002; Young quoted in “Giant Antarctic Ice Shelves Shatter and Break Away,” op. cit. note 53.
57. Boesch cited in Bette Hileman, “Consequences of Climate Change,” Chemical & Engineering News, 27 March 2000, pp. 18–19.
58. World Bank, World Development Report 1999/2000 (New York: Oxford University Press, 2000), p. 100; population from United Nations, op. cit. note 26; Shanghai population from United Nations, World Urbanization Prospects: The 2003 Revision (New York: 2004); Shanghai from Stuart R. Gaffin, High Water Blues: Impacts of Sea Level Rise on Selected Coasts and Islands (Washington, DC: Environmental Defense Fund, 1997), p. 27.
59. James E. Neumann et al., Sea-level Rise & Global Climate Change: A Review of Impacts to U.S. Coasts (Arlington, VA: Pew Center on Global Climate Change, 2000); Gaffin, op. cit. note 58.
60. IPCC, op. cit. note 11, p. 665.
Copyright © 2006 Earth Policy Institute