Antarctic melt-down: no reason to expect it just yet

A recurring horror story warns that man-made warming could melt the Antarctic ice and flood a lot of valuable real estate. While that's legitimate scientific speculation, the story usually omits scientists' caveats, raising needless fear overwhat is at best a vaguely defined threat.

It's refreshing, then, to have D. E. Sugden and C. M. Clapperton of Scotland's University of Aberdeen point out that, on present evidence, "there is no need to fear imminent West Antarctic ice sheet collapse due to climate warming. . . ." In fact, they report in Nature that field studies indicate the ice has been building over the past 8,000 years, rather than undergoing collapse in response to post-glacial warming as some scientists have suggested. And they see no reason to expect imminent collapse from warming due to increased atmospheric carbon dioxide (CO[2]) content from burning fossil fuels -- the man-made effect at issue.

This undermines the alarmist stories. But it does not imply that scientists themselves should neglect the need to understand thoroughly the possible effect of rising CO[2] levels on Antarctic ice -- a need that was the original point of concern.

J. H. Mercer of Ohio State University raised this concern in January 1978 when he pointed out that the West Antarctic ice sheet in particular appeared vunerable to sudden collapse due to CO[2]-induced warming. This could raise global sea level by about 5 meters, flooding many cities and much farmland. However, he emphasized that the possibility arose from studies with computer models of climate that "are known to be crude and oversimplified."

Thus, Mercer was not raising an alarm about a possible climatic disaster. He was urging more incisive study to see whether or not any alarm were justified. "More sophisticated modeling may show that the outlook is less than this, but on the other hand, it may show that the situation is even more threatening. The urgent need for this sophisticated modeling is evident," he said.

This point has tended to be lost as some environment lists have picked up on Antarctic melting as a reason to hold back now on intensive development of coal as an energy source. Many news reports have followed this theme, giving the impression that the great Antarctic melt-down is a distinct possibility rather than an unsubstantiated hypothesis. It did not help public perception for a prominent scientist who advocates a hold-down on coal to pose on the steps of the US Capitol showing how high the waters would come.

Such posturing does not change the basic fact that the melt-down scenario is too hypothetical to justify any public policy other than the decision already taken by the US Department of Energy to support research to gain more understanding. meanwhile, as Sugden and Clapperton note, there is no need to entertain groundless fears.

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