"The world is a much more hopeful place because of the work and life of Lester Brown. World on the Edge should be read by everyone who wants to see a better life for their children, which is just about everybody." —Ted Glick, Policy Director of the Chesapeake Climate Action Network
Chapter 3. Climate Change and the Energy Transition: Melting Ice, Rising Seas
Ice is melting so fast that even climate scientists are scrambling to keep up with the shrinkage of ice sheets and glaciers. The melting of the earth’s largest ice sheets—Greenland and West Antarctica—would raise sea level dramatically. If the Greenland ice sheet were to melt entirely, it would raise sea level 23 feet. Melting of the West Antarctic ice sheet, the most vulnerable portion of the Antarctic ice because of its exposure to both warming air and warming ocean water, would eventually raise sea level 16 feet. Many of the world’s coastal cities would be under water; over 600 million coastal dwellers would be forced to move. 26
Assessing the prospects for the Greenland ice sheet begins with looking at the warming of the Arctic region. A 2005 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 climbed by 3–4 degrees Celsius (5–7 degrees Fahrenheit) over the last half-century. Robert Corell, the ACIA chairman, says this region “is experiencing some of the most rapid and severe climate change on Earth.” 27
In testimony before the U.S. Senate Commerce Committee, Sheila Watt-Cloutier, speaking on behalf of the 155,000 Inuits who live in Alaska, Canada, Greenland, and the Russian Federation, described their struggle to survive in the rapidly changing Arctic climate as “a snapshot of what is happening to the planet.” For example, as the sea ice shrinks it threatens the ice-dwelling seals, a basic food source for the Inuit. She called the warming of the Arctic “a defining event in the history of this planet.” 28
The ACIA report noted that the retreat of the sea ice has devastating consequences for polar bears, whose very survival may be at stake. A subsequent report indicated that polar bears, desperate for food, are turning to cannibalism. Two thirds of the polar bear population could be gone by 2050. 29
There is new evidence that Arctic sea ice is melting faster than previously thought. Scientists from the National Snow and Ice Data Center and NCAR examining data on Arctic Ocean summer ice since 1953 concluded that the ice is melting much faster than climate models had predicted. They found that from 1979 to 2006 the summer sea ice shrinkage accelerated to 9.1 percent a decade. In the summer of 2007, a record melt year, Arctic sea ice shrank to an area some 20 percent smaller than the previous record set in 2005. Recent evidence that the multiyear sea ice is not recovering in winter and therefore thinning overall only adds to concern about the ice cap’s future. 30
Walt Meier, a researcher at the U.S. National Snow and Ice Data Center, views the winter shrinkage with alarm. He believes there is “a good chance” that the Arctic tipping point has been reached. Some scientists now think that the Arctic Ocean could be ice-free in summer as early as 2015, but in early 2009 Warwick Vincent, director of the Center for Northern Studies at Laval University in Quebec, reported that this could happen by 2013. Arctic scientist Julienne Stroeve observed that the shrinking Arctic sea ice may have reached “a tipping point that could trigger a cascade of climate change reaching into Earth’s temperate regions.” 31
Scientists have long been concerned that a self-reinforcing trend may be starting to kick in as the sea ice shrinks. When incoming sunlight strikes the ice in the Arctic Ocean, up to 70 percent of it is reflected back into space. Only 30 percent is absorbed. As the Arctic sea ice melts, however, and the incoming sunlight hits the much darker open water, only 6 percent is reflected back into space and 94 percent is converted into heat. This albedo effect helps explain the accelerating shrinkage of the Arctic sea ice and the rapidly rising regional temperature. 32
If all the ice in the Arctic Ocean melts, it will not affect sea level because the ice is already in the water. But it will lead to a much warmer Arctic region as more of the incoming sunlight is converted to heat. And since Greenland lies largely within the Arctic Circle, its ice sheet—up to 1.6 kilometers (1 mile) thick in places—is beginning to show the effects. 33
Several recent studies report accelerated melting of the Greenland ice sheet. In September 2006, a University of Colorado team study published in Nature indicated that between April 2004 and April 2006 Greenland lost ice 2.5 times faster than during the preceding two years. In October 2006, a team of NASA scientists reported that the flow of glaciers into the sea was accelerating. Eric Rignot, a glaciologist at NASA’s Jet Propulsion Laboratory, said that “none of this has been predicted by numerical models, and therefore all projections of the contribution of Greenland to sea level [rise] are way below reality.” 34
In late summer 2007 scientists at a symposium in Ilulissat, Greenland, said that the Greenland icecap is melting so fast that it is triggering minor earthquakes as pieces of ice weighing millions of tons break off and slide into the sea. ACIA chairman Corell reported that “we have seen a massive acceleration of the speed with which these glaciers are moving into the sea.” The Ilulissat (Jakobshavn Isbrae) glacier, a large outlet glacier on Greenland’s southwest coast, is moving at 2 meters per hour on a front 8 kilometers (5 miles) wide and 900 meters deep. 35
Data gathered by NASA satellites indicated that Greenland’s floating ice shelves shrank by 24 square miles in 2007. In the summer of 2008 this loss jumped to 71 square miles, nearly tripling. Part of this loss was observed directly by an Ohio State University research team, which saw a massive 11-square-mile chunk of ice break off from the Petermann Glacier in northern Greenland. An upstream crack in the glacier suggested an even larger chunk would be breaking off soon. 36
What scientists once thought was a simple linear process—that at the surface an ice sheet melts a fixed amount each year, depending on the temperature—is now seen to be much more complex. As the surface ice begins to melt, some of the water filters down through cracks in the glacier, lubricating the surface between the glacier and the rock beneath it. This accelerates the glacial flow and the calving of icebergs into the surrounding ocean. The relatively warm water flowing through the moulins (deep holes) and cracks in the ice sheet also carries surface heat deep inside it far faster than it would otherwise penetrate by simple conduction. 37
At the other end of the earth, the 2-kilometer-thick Antarctic ice sheet, which covers an area one and a half times the size of the United States and contains 70 percent of the world’s fresh water, is also beginning to melt. Ice shelves formed by the flow of glaciers from the continent into the surrounding seas are breaking up at an alarming rate. 38
The 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. Even veteran ice watchers are amazed at how quickly the disintegration is occurring. “The speed of it is staggering,” said 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 Larsen, the average temperature has risen 2.5 degrees Celsius over the last five decades. 39
When Larsen A, a huge ice shelf on the eastern side 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 (4,250 square miles)—broke off the Ross Ice Shelf on the south side of the continent. 40
After Larsen A broke up, it was only a matter of time, given the rise in temperature in the region, before neighboring Larsen B would do the same. 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 Rhode Island–sized chunk of ice broke off the Thwaites Glacier. 41
In May 2007, a team of scientists from NASA and the University of Colorado reported satellite data showing widespread snow-melt on the interior of the Antarctic ice sheet over an area the size of California. This melting in 2005 was 900 kilometers inland, only about 500 kilometers from the South Pole. Team member Konrad Steffen observed, “Antarctica has shown little to no warming in the recent past with the exception of the Antarctic Peninsula, but now large regions are showing the first signs of the impacts of warming.” 42
Ice sheets are now breaking up at a remarkable rate. At the end of February 2008, a NASA satellite caught a Manhattan-sized piece of the Wilkins ice shelf breaking up. Within 10 days, the 5,000-square-mile ice shelf lost 160 square miles of ice. 43
Just over a year later, a NASA satellite image showed the collapse of an ice bridge that signaled the final demise of the Wilkins ice shelf. Yet another chunk of the West Antarctic ice sheet is disappearing. NASA reports that the Wilkins breakup is the tenth major Antarctic ice sheet to collapse in recent times. 44
When ice shelves already largely 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 can accelerate, leading to a thinning of the ice sheet on the edges of the Antarctic continent, thus contributing to sea level rise. 45
The accelerated melting of both the Greenland and West Antarctic ice sheets is leading to much higher projected rises in sea level for this century. The IPCC projections of 18–59 centimeters during this century do not fully include the dynamic processes accelerating ice melt on the Greenland and West Antarctic ice sheets. As scientists take these into account, they are revising their projections. In 2008, a report by the U.S. Climate Change Science Program indicated that the IPCC sea level rise is likely an underestimate. A team led by W. Tad Pfeffer of the Institute of Arctic and Alpine Research at the University of Colorado concluded in September 2008 that with melting continuing to accelerate, the world could see a sea level rise of 0.8–2 meters (3–6 feet) by 2100. 46
The International Institute for Environment and Development (IIED) has analyzed the effect of a 10-meter rise in sea level, providing a sense of how humanity would be affected if the two ice sheets started to disappear. The IIED study begins by pointing out that 634 million people currently live along coasts at or below 10 meters above sea level, most of them in cities and rice-growing river deltas. 47
One of the most vulnerable countries is China, with 144 million potential climate refugees. India and Bangladesh are next, with 63 million and 62 million respectively. Viet Nam has 43 million vulnerable people, and Indonesia 42 million. Others in the top 10 include Japan with 30 million, Egypt with 26 million, and the United States with 23 million. 48
It is difficult to imagine the displacement of so many people. Some of the refugees could simply retreat to higher ground within their own country. Others—facing extreme crowding in the interior regions of their homeland or a total inundation of their low-lying island countries—would seek refuge elsewhere. Rising-sea refugees in already crowded Bangladesh would likely try to do this, which helps explain why neighboring India has built a fence along its border.
Not only would some of the world’s largest cities, such as Shanghai, Kolkata, London, and New York, be partly or entirely inundated, but vast areas of productive farmland would also be lost. The rice-growing river deltas and floodplains of Asia, including the Gangetic and Mekong deltas, would be covered with salt water, depriving Asia of part of its food supply.
26. UNEP, op. cit. note 2; Gordon McGranahan et al., “The Rising Tide: Assessing the Risks of Climate Change and Human Settlements in Low Elevation Coastal Zones,” Environment and Urbanization, vol. 18, no. 1 (April 2007), pp. 17–37.
27. Arctic Climate Impact Assessment (ACIA), Impacts of a Warming Arctic (Cambridge, U.K.: Cambridge University Press, 2004); “Rapid Arctic Warming Brings Sea Level Rise, Extinctions,” Environment News Service, 8 November 2004.
28. J. R. Pegg, “The Earth is Melting, Arctic Native Leader Warns,” Environment News Service, 16 September 2004; ACIA, op. cit. note 27, p. 8.
29. ACIA, op. cit. note 27; Steven C. Amstrup, Bruce G. Marcot, and David C. Douglas, Forecasting the Range-wide Status of Polar Bears at Selected Times in the 21st Century (Reston, VA: U.S. Geological Survey (USGS), 2007), p. 2.
30. Julienne Stroeve et al., “Arctic Sea Ice Decline: Faster than Forecast,” Geophysical Research Letters, vol. 34 (May 2007); National Snow and Ice Data Center (NSIDC), “Arctic Sea Ice Shatters All Previous Record Lows,” press release (Boulder, CO: 1 October 2007); R. Kwok et al., “Thinning and Volume Loss of the Arctic Ocean Sea Ice Cover: 2003–2008,” Journal of Geophysical Research, vol. 114 (7 July 2009).
31. David Adam, “Meltdown Fear as Arctic Ice Cover Falls to Record Winter Low,” Guardian (London), 15 May 2006; Kevin Rollason, “Arctic to See First Ice-Free Summer in 2015,” Canwest News Service (Canada), 6 December 2008; Vincent cited in David Ljunggren, “Arctic Summer Ice Could Vanish by 2013: Expert,” Reuters, 5 March 2009; Stroeve quoted in “Arctic Ice Retreating 30 Years Ahead of Projections,” Environment News Service, 30 April 2007.
32. NSIDC, “Processes: Thermodynamics: Albedo,” at nsidc.org/seaice/processes/albedo.html, viewed 26 July 2007.
33. UNEP, op. cit. note 2.
34. J. L. Chen, C. R. Wilson, and B. D. Tapley, “Satellite Gravity Measurements Confirm Accelerated Melting of Greenland Ice Sheet,” Science, vol. 313 (29 September 2006), pp. 1,958–60; Isabella Velicogna and John Wahr, “Acceleration of Greenland Ice Mass Loss in Spring 2004,” Nature, vol. 443 (21 September 2006), pp. 329–31; S. B. Luthke et al., “Recent Greenland Ice Mass Loss from Drainage System from Satellite Gravity Observations,” Science, vol. 314 (24 November 2006), pp. 1,286–89; “Gravity Measurements Confirm Greenland’s Glaciers Precipitous Meltdown,” Scientific American, 19 October 2006.
35. Paul Brown, “Melting Ice Cap Triggering Earthquakes,” Guardian (London), 8 September 2007; Robert W. Corell, discussion with Jignasha Rana, Earth Policy Institute, 15 July 2009.
36. Ohio State University, “Greenland’s Glaciers Losing Ice Faster This Year than Last Year, Which Was Record-Setting Itself,” news release (Columbus, OH: 13 December 2008).
37. H. Jay Zwally et al., “Surface Melt-Induced Acceleration of Greenland Ice-Sheet Flow,” Science, vol. 297 (12 July 2002), pp. 218–22.
38. U.S. Department of Energy (DOE), Energy Information Administration (EIA), “Antarctica: Fact Sheet,” at www.eia.doe.gov, September 2000.
39. “Giant Antarctic Ice Shelves Shatter and Break Away,” Environment News Service, 19 March 2002; Vaughan quoted in Andrew Revkin, “Large Ice Shelf in Antarctica Disintegrates at Great Speed,” New York Times, 20 March 2002.
40. “Breakaway Bergs Disrupt Antarctic Ecosystem,” Environment News Service, 9 May 2002; “Giant Antarctic Ice Shelves Shatter and Break Away,” op. cit. note 39.
41. NSIDC, “Larsen B Ice Shelf Collapses in Antarctica,” at nsidc.org/news/press/larsen_B/2002.html, 21 March 2002; “Breakaway Bergs Disrupt Antarctic Ecosystem,” op. cit. note 40; “Giant Antarctic Ice Shelves Shatter and Break Away,” op. cit. note 39.
42. University of Colorado at Boulder, “NASA, CU-Boulder Study Shows Vast Regions of West Antarctica Melted in Recent Past,” press release (Boulder: 15 May 2007).
43. Peter Brown, “NASA Satellites Watch Polar Ice Shelf Break into Crushed Ice,” Scientific American, July 2008.
44. NASA Earth Observatory, “Wilkins Ice Bridge Collapse,” at earthobservatory.nasa.gov/IOTD/view.php?id=37806, posted 8 April 2009.
45. Michael Byrnes, “New Antarctic Iceberg Split No Threat,” Reuters, 20 May 2002.
46. Robin McKie, “Scientists to Issue Stark Warning Over Dramatic New Sea Level Figures,” Guardian (London), 8 March 2009; IPCC, op. cit. note 1, p. 13; Pfeffer, Harper, and O’Neel, op. cit. note 2; USGS, Synthesis and Assessment Product 3.4: Abrupt Climate Change (Washington, DC: 2009), p. 9.
47. McGranahan et al., op. cit. note 26.
Copyright © 2009 Earth Policy Institute