As Climate Shifts, Antarctic Ice Sheet Is Growing

The vast East Antarctic Ice Sheet -- a 2-mile-thick wasteland larger than Australia, drier than the Sahara and as cold as a Martian spring -- increased in mass every year from 1992 to 2003 because of additional annual snowfall, an analysis of satellite radar measurements showed.

"It is an effect that has been predicted as a likely result of climate change," said David Vaughan, an independent expert on the ice sheets at the British Antarctic Survey in Cambridge, England.

In a region known for the lowest temperatures recorded on Earth, it normally is too cold for snow to form across the 2.7 million square miles of the ice sheet. Any additional annual snowfall in East Antarctica, therefore, is almost certainly attributable to warmer temperatures, four experts on Antarctica said.

"As the atmosphere warms, it should hold more moisture," said climatologist Joseph R. McConnell at the Desert Research Institute in Reno, who helped conduct the study. "In East Antarctica, that means there should be more snowfall."

The additional snowfall is enough to account for 45 billion tons of water added to the ice sheet every year, just about equal to the amount of water flowing annually into the ocean from the melting Greenland icecap, the scientists reported in research published online Thursday by the journal Science.

Rising sea level, which could swamp many coastal and island communities, is considered one of the most serious potential consequences of global warming, according to the most recent assessment by the United Nations' Intergovernmental Panel on Climate Change.

Overall, sea level is estimated to be rising by 1.8 millimeters a year worldwide because of the expansion of warming water and the added outwash from melting glaciers in Greenland, Alaska, tropical highlands and some areas of Antarctica.

Every millimeter of increased sea level corresponds to about 350 billion tons of water a year.

The growth in the East Antarctic icecap is enough to slow sea-level rise by a fraction of that -- about 0.12 millimeter a year -- the researchers reported.