Scientific models predict that global warming will occur first and worst at the poles. But testing that theory has been tough, since good data on temperatures in the Arctic have been hard to come by. Now, thanks to the end of the cold war, scientists have examined U. S. and Russian measurements taken from 1950 to 1990. Their findings, published in the Jan. 28 Nature, are a surprise. Says Jonathan D. Kahl, a climatologist at the University of Wisconsin: "The predicted widespread warming in the Arctic is not observed."
By no means is the debate over, though. For one thing, Kahl points out that 40 years may be too short to spot a warming trend. And John E. Walsh, a University of Illinois climatologist, adds that Russia's drifting ice stations, from which many balloon-borne instruments were released, may not have been in the best places to detect warming. Still, the new study does strongly suggest that the computer models don't yet do justice to the Arctic's complicated climate. "My guess is that there probably is some warming caused by greenhouse gases, but it may be balanced by other factors, such as changes in cloud cover," says Kahl. "It's very confusing."