for National Geographic News
The western part of Antarctica is shedding ice much faster today than it was just ten years ago, according to new satellite measurements.
The measurements, which surveyed the coasts of nearly the entire continent, suggest that climate models underestimate how quickly Antarctica responds to ongoing global warming, said study co-author Jonathan Bamber of the University of Bristol in England.
Many past studies have tried to estimate how much ice Antarctica is losing.
(Related: "Hundreds of Glaciers Melting Faster in Antarctica" [June 6, 2007].)
But the new study is the first to show that this loss is accelerating, at least in western Antarctica and the Antarctic Peninsula, the researchers say.
"In all the ice sheet models we have at present for Antarctica, things happen very slowly," Bamber said.
"[But] we're seeing things happen rather quickly."
They found that for Antarctica overall, the ice loss increased about 75 percent over the ten-year period, from 112 gigatons of ice per year in 1996 to 196 gigatons of ice per year in 2006.
As to whether Antarctica will lose or gain ice as global warming proceeds, the measurements disagree with existing climate models that suggest "[the ice sheet] is going to get bigger because of increased snowfall with warming temperatures," Bamber said.
"We don't see that. We see the ice sheet losing mass," he said. "So there's a bit of a paradigm shift in what the ice sheet has done recently and what it could do in the future."
Scientists are concerned the melting ice will contribute to a dangerous sea level rise.
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