"Eliminating water shortages depends on a global attempt to raise water productivity similar to the effort launched a half-century ago to raise land productivity, an initiative that has nearly tripled the world grain yield per hectare." –Lester R. Brown, World Facing Huge New Challenge on Food Front in Plan B 3.0: Mobilizing to Save Civilization
Chapter 4. Rising Temperatures and Rising Seas: Rising Temperature and Its Effects
Scientists at the National Aeronautics and Space Administration’s Goddard Institute for Space Studies gather data from a global network of some 800 climate-monitoring stations to measure changes in the earth’s average temperature. Their records go back 125 years, to 1880. 8
Since 1970, the earth’s average temperature has risen by 0.8 degrees Celsius, or nearly 1.4 degrees Fahrenheit. During this span, the rise in temperature each decade was greater than in the preceding one. (See Figure 4–1.) Meteorologists note that the 22 warmest years on record have come since 1980. And the six warmest years since recordkeeping began in 1880 have come in the last eight years. Three of these six—2002, 2003, and 2005—were years in which major food-producing regions saw their crops wither in the face of record temperatures. 9
The amount of CO 2 in the atmosphere has risen substantially since the Industrial Revolution, with most of the rise coming since recordkeeping began in 1959. Since then it has risen every year, making this one of the world’s most predictable environmental trends. As shown in Figure 4–2, CO 2 levels turned sharply upward around 1960. Roughly a decade later, around 1970, the temperature too began to climb. 10
Against this backdrop of record increases, the projections of the Intergovernmental Panel on Climate Change (IPCC) that the earth’s average temperature will rise 1.4–5.8 degrees Celsius (2.5–10.4 degrees Fahrenheit) during this century seem all too possible. Recent data on the temperature rise in some northern regions—such as Alaska, western Canada, and Siberia—coupled with the accelerated melting of the Greenland ice sheet, the melting of glaciers in mountain ranges throughout the world, and the likelihood at this writing that the global temperature for 2005 will set yet another record high all suggest that the global temperature rise will be close to the upper end of the IPCC projected range. Such an increase—of 5.8 degrees Celsius by 2100, a rise comparable to that between the last Ice Age and today—will create a world far different from the one we know. 11
At a practical level, the IPCC projected rise in temperature is a global average. In reality, the rise will be very uneven. It will be much greater over land than over oceans, in the higher latitudes than over the equator, and in the continental interiors than in coastal regions. 12
Higher temperatures diminish crop yields, melt the snow/ice reservoirs in the mountains that feed the earth’s rivers, cause more destructive storms, increase the area affected by drought, and cause more frequent and destructive wild fires. 13
In a paper presented at the American Meteorological Society’s annual meeting in San Diego, California, in January 2005, a team of scientists from the National Center for Atmospheric Research reported a dramatic increase in the earth’s land surface affected by drought over the last few decades. They reported that the land experiencing very dry conditions expanded from less than 15 percent of the earth’s total land area in the 1970s to roughly 30 percent by 2002. They attributed part of the change to a rise in temperature and part to reduced precipitation, with high temperatures becoming progressively more important during the latter part of the period. Lead author Aiguo Dai reported that most of the drying was concentrated in Europe and Asia, Canada, western and southern Africa, and eastern Australia. 14
Researchers with the U.S. Department of Agriculture’s Forest Service reported that even a 1.6-degree-Celsius rise in summer temperature could double the area of wildfires in the 11 western states. The study, published in the August 2004 issue of Conservation Biology, drew on 85 years of fire and temperature records. 15
The National Wildlife Federation (NWF) reports that if temperatures continue to rise, by 2040 one out of five of the Pacific Northwest’s rivers will be too hot for salmon, steelhead, and trout to survive. Paula Del Giudice, Director of the Federation’s Northwest Natural Resource Center, notes that “global warming will add an enormous amount of pressure onto what’s left of the region’s prime cold-water fish habitat.” 16
Ecosystems everywhere will be affected by higher temperatures, sometimes in ways we cannot easily predict. The Pew Center for Global Climate Change sponsored a mega-study analyzing some 40 scientific reports that link temperature with changes in ecosystems. Among the many changes reported are spring arriving nearly two weeks earlier in the United States, tree swallows nesting nine days earlier than they did 40 years ago, and a northward shift of red fox habitat that has it encroaching on the Arctic fox’s range. Inuits were surprised by the appearance of robins, a bird they had never seen before. Indeed, there is no word in Inuit for “robin.” 17
Hector Galbraith of the University of Colorado-Boulder, a co-author of the Pew study, indicated that “the effects of this change are occurring much more rapidly than...expected.” He also said “that ecosystems are much more sensitive to climate change than believed a decade ago.” A study sponsored by Conservation International has predicted that continued climate change could drive more than a quarter of all land animals and plants to extinction. 18
Douglas Inkley, NWF Senior Science Advisor and senior author of a report to the Wildlife Society, notes, “We face the prospect that the world of wildlife that we now know—and many of the places we have invested decades of work in conserving as refugees and habitats for wildlife—will cease to exist as we know them, unless we change this forecast.” 19
7. “Awful Weather We’re Having,” The Economist, 2 October 2004; Richard Milne, “Hurricanes Cost Munich Re Reinsurance,” Financial Times, 6 November 2004.
8. J. Hansen, NASA’s Goddard Institute for Space Studies (GISS), “Global Temperature Anomalies in 0.1 C,” at http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt, updated September 2005; climate monitoring stations from Reto A. Ruedy, GISS, e-mail to Janet Larsen, Earth Policy Institute, 14 May 2003.
9. Figure 4–1 from Hansen, op. cit. note 8; crops from USDA, op. cit. note 3; USDA, Grain: World Markets and Trade (Washington, DC: various months).
10. Figure 4–2 from Keeling and Whorf, op. cit. note 2, with historical carbon dioxide estimate in data from Seth Dunn, “Carbon Emissions Dip,” in Worldwatch Institute, Vital Signs 1999 (New York: W.W. Norton & Company, 1999), pp. 60–61; update from Hansen, op. cit. note 8.
11. Intergovernmental Panel on Climate Change (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); Arctic Climate Impact Assessment (ACIA), Impacts of a Warming Arctic (Cambridge, U.K.: Cambridge University Press, 2004); National Snow and Ice Data Center (NSIDC), “Arctic Sea Ice Shrinking, Greenland Ice Sheet Melting, According to Study,” press release, 7 December 2002; Frank Paul et al., “Rapid Disintegration of Alpine Glaciers Observed with Satellite Data,” Geophysical Research Letters, vol. 31, L21402 (12 November 2004); Hansen, op. cit. note 8; comparison to time since Ice Age from Warren Washington, cited in Stephen Phillips, “Ignoring Climate Will Land Us in Hot Water,” Times Higher Education Supplement, 7 February 2003.
12. IPCC, op. cit. note 11.
13. Shaobing Peng et al., “Rice Yields Decline with Higher Night Temperature from Global Warming,” Proceedings of the National Academy of Sciences, 6 July 2004, pp. 9971–75; John Krist, “Water Issues Will Dominate California’s Agenda This Year,” Environmental News Network, 21 February 2003; Thomas R. Knutson and Robert E. Tuleya, “Impact of CO 2-Induced Warming on Simulated Hurricane Intensity and Precipitation: Sensitivity to the Choice of Climate Model and Convective Parameterization,” Journal of Climate, vol. 17, no. 18 (15 September 2004), pp. 3477–95; Aiguo Dai, Kevin E. Trenberth, and Taotao Qian, “A Global Dataset of Palmer Drought Severity Index for 1870–2002: Relationship with Soil Moisture and Effects of Surface Warming,” Journal of Hydrometeorology, vol. 5 (December 2004), pp. 1117–30; “Even Modest Climate Change Means More and Larger Fires,” Environment News Service, 31 August 2004.
14. National Center for Atmospheric Research and UCAR Office of Programs, “Drought’s Growing Reach: NCAR Study Points to Global Warming as Key Factor,” press release (Boulder, CO: 10 January 2005); Dai, Trenberth, and Qian, op. cit. note 13.
15. Donald McKenzie et al., “Climatic Change, Wildfire, and Conservation,” Conservation Biology, vol. 18, no. 4 (August 2004), pp. 890–902.
16. “Elizabeth Gillespie, “Global Warming May Be Making Rivers Too Hot: Cold-Water Fish Will Struggle, Report Says,” Seattle Post-Intelligencer, 24 March 2005.
17. Camille Parmesan and Hector Galbraith, Observed Impacts of Global Climate Change in the U.S. (Arlington, VA: Pew Center on Global Climate Change, 2004); DeNeen L. Brown, “Signs of Thaw in a Desert of Snow, Washington Post, 28 May 2002.
18. Parmesan and Galbraith, op. cit. note 17; J. R. Pegg, “Global Warming Disrupting North American Wildlife,” Environment News Service, 16 December 2004.
19. Douglas B. Inkley et al., Global Climate Change and Wildlife in North America (Bethesda, MD: The Wildlife Society, December 2004).
Copyright © 2006 Earth Policy Institute