
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, July 15, 1993                   TAG: 9307150200
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A-1   EDITION: METRO 
SOURCE: The New York Times
DATELINE:                                 LENGTH: Medium

CLIMATE SHIFTS ARE WIDE AND QUICK, STUDY SAYS

To the astonishment of climate specialists, an analysis of ice extracted from the full depth of the Greenland ice sheet has shown that except for the 8,000 to 10,000 years since the last glacial epoch, the climate over the past 250,000 years has changed frequently and abruptly.

The findings suggest that the period of stable climate in which human civilization has flourished might be unusual, and that the current climate may get either warmer or colder much more quickly than had been believed - in spans of decades or even less.

The data are likely to bolster concern that future changes in climate might not be spread over many centuries, allowing farmers to adjust to altered growing conditions and coastal cities to deal with rising sea levels, for example.

Scientists have speculated for years about the effects of climate warming. Even a rise of a few feet in sea level would flood many food-producing regions and populous areas.

The 40 scientists on the Greenland Ice Core Project said their data showed that a significantly warmer period and a significantly colder period had occurred during the last interval between glacial epochs, about 115,000 to 135,000 years ago. They said they could not tell whether that meant similar changes were in store.

Previous studies had shown that there were abrupt changes in climate during glacial epochs, but the new results, which are being reported today in the journal Nature, unexpectedly showed that the same was true in the periods when glaciers had retreated. In one "catastrophic event" at the height of the last interglacial period the average temperature plunged 25 degrees Fahrenheit, to ice-age levels, for about 70 years, the scientists say.

The authors did not have an explanation for the rapid shifts. They also said it was a mystery why the climate of the last 8,000 to 10,000 years had been "strangely stable."

by CNB