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GLOBAL WARMING, IF IT OCCURS, COULD SLOW SEA LEVEL RISE
Ice Accumulation at the Poles Likely to Offset Glacial Melting

SAN FRANCISCO, CALIFORNIA, DECEMBER 9, 1997---Fears of a disastrous rise in sea level due to a possible future global warming may prove groundless, according to physicist S. Fred Singer of The Science & Environmental Policy Project in Fairfax, Virginia. In a research paper presented today in San Francisco at the Annual Meeting of the American Geophysical Union, Singer shows an anti-correlation between sea surface temperature and sea level rise, a result contrary to that forecast by the UN's scientific advisory group, the Intergovernmental Panel on Climate Change (IPCC).

Sea level has been rising steadily at an average rate of about 7 inches per century, notes Singer. Most researchers attribute this rise to factors unrelated to climate fluctuations or to any human influences. The IPCC has predicted with some certainty that any future warming of the earth's climate--resulting in glacial melting and thermal expansion of ocean water--would accelerate this rise.

Singer points to an offsetting factor. "As temperatures warm," he says, "the rate of ocean evaporation accelerates, which leads to more precipitation. This would come down over the polar regions as snow, thickening the ice caps of Greenland and the Antarctic and transferring water from the oceans to the ice sheets.

Scientists have known for some time that in the event of a global warming, both mechanisms--glacial melting/thermal expansion and increased precipitation/thickening ice caps--would be in play. It wasn't known, however, which mechanism would be the most important.

Last fall, Singer observed in a paper published by A. Trupin and J. Wahr in the Geophysical Journal International that the steady rise in sea level slowed significantly during the period from 1920 to 1940, a time of rapid warming as the earth recovered from the "Little Ice Age." Singer decided to do a statistical analysis of the available data on sea level, and to compare it with sea surface temperature and global temperature. What he discovered was a strong anti-correlation that held over the entire record, since the beginning of this century.

"Sea level has been going up about 7 inches per century for reasons other than climate change, and that will likely continue," says Singer. "But what the data show is that when temperatures get warmer the rate of rise slows considerably." If this is confirmed by direct measurement of annual ice accumulation at the poles, it would indicate that with any future warming a transfer of water to the polar regions, in the form of ice, would more than offset any glacial melting and thermal expansion. "And that would be good news," says Singer, "to those concerned about coastal flooding."

S. Fred Singer is Distinguished Research Professor at George Mason University and Professor Emeritus of environmental sciences at the University of Virginia. Previous academic and government positions include Dean of the School of Environmental and Planetary Sciences, University of Miami; chief scientists, U.S. Department of Transportation; Deputy Assistant Administrator, Environmental Protection Agency; and first Director, U.S. Weather Satellite Service (now part of NOAA).

See also The Sky Isn't Falling, and the Ocean Isn't Rising.