Greenland Ice Shrinking Faster than Expected

By MIKE TONER The Atlanta Journal-Constitution etc.

Published on: 10/20/06

NASA reported Thursday that Greenland's polar ice cap, in an apparent response to changing climate, has undergone "dramatic ice mass losses" over the past two years.

Satellite measurements have provided precise new evidence about the rate at which climate change is shrinking Greenland's polar ice sheet.

Researchers have long believed that any warming of the polar regions would produce two effects — increased melting of ice during the summer and an increase in the winter snows that replenish it.

At least in Greenland, they now say the melting is easily outstripping winter snowfall. In a report in the journal Science they conclude that since 2003, Greenland has lost 41 cubic miles of ice along the coast and gained only 14 cubic miles from increased snowfall in the interior.

The ice mass loss in this study is less than half that reported in

other recent research, NASA said in a statement, but it still shows

that Greenland is losing 20 percent more mass than it gets in new

snowfall each year.

The Greenland ice sheet is considered an early indicator of the

consequences of global warming, so even a slower ice melt there raises

concerns.

"This is a very large change in a very short time," said Jay Zwally, a

co-author of the study. "In the 1990s, the ice sheet was growing

inland and shrinking significantly at the edges, which is what climate

models predicted as a result of global warming.

"Now the processes of mass loss are clearly beginning to dominate the

inland growth, and we are only in the early stages of the climate

warming predicted for this century," Zwally said.

If Greenland's ice sheets melted completely, it would raise sea level around the world by more than 20 feet.

Scientists don't think such a massive change is likely, but they note that even the current imbalance is equivalent to six years of average water flow from the Colorado River.