Do Glaciers And Ice Sheets Show Global Warming?
March 30, 1999
Some global warming theorists say receding glaciers are evidence that climate change caused by humans is underway. But mid-latitude glaciers are only 6 percent of the world's total ice mass, while the other 94 percent is in Antarctica and Greenland. The latter show no evidence of global warming, while evidence from other glaciers is mixed -- suggesting ice masses are a poor predictor of climate change.
- For instance, Africa's Mount Kenya lost 92 percent of its mass over the last century, while the number of glaciers in Spain fell from 27 in 1980 to just 13 today.
- However, several Swiss glaciers are advancing even though Switzerland has experienced a decade of mild winters, warmer summers and less rainfall.
- Furthermore, global warming models say the polar regions should have warmed 2-5°F since 1940; but from 1955 to 1990 the Arctic cooled by 1°F.
- And a study in Geophysical Research Letters reports that the West Greenland Ice Sheet has thickened by up to seven feet since 1980.
- Over the past 10,000 years, say scientists, several glaciers in Antarctica expanded during conditions a lot warmer than today.
Martin Beniston of the Institute of Geography at the University of Fribourg says the response time of glaciers to climatic changes varies with size, exposure and altitude. A polar ice sheet might take 10,000-100,000 years to respond, while a small mountain glacier might take 100 to 1,000 years. Thus glaciers today may be reacting to warming in the 11th century or an even warmer period 6,000 years ago.
Interestingly, Greenpeace's Climate Impacts Database notes that "the new data suggest strongly that Antarctica's response to future warming will be an increase in mass balance" -- or more ice, not less.
Source: John Carlisle, "Behavior of World's Glaciers Fails to Prove Global Warming Theory," National Policy Analysis No. 235, February 1999, National Center for Public Policy Research, 777 N. Capitol Street, N.E., Suite 803, Washington, D.C. 20002, (202) 371-1400.
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