Greenland's Biggest Outlet Glacier Doubles Flow Rate Between 1997-2003

[hatrack]

WASHINGTON, DC, December 6, 2004 (ENS) – "The world's fastest glacier doubled the speed of its ice flow between 1997 and 2003, and its acceleration coincides with very rapid thinning, new research funded by NASA has found. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area.

The stream's near doubling of ice flow from land into the ocean is important, scientists said, because this one glacier has increased the rate of sea level rise by four percent of the 20th century rate of increase. "This speedup is the most dramatic change observed in a large glacier to date," said Mark Fahnestock, coauthor of the new study and a glaciologist with the Institute for the Study of Earth, Oceans, and Space (EOS). "Observing a doubling of the flow of one of the large rivers of ice draining the Greenland Ice Sheet in such a short time raises questions about the nature and stability of the ice sheet." The study, published Friday in the journal "Nature," relied on data from satellites and airborne lasers to derive speed and thickness of the glacier between 1985 and 2003.

The data showed that the glacier slowed down from a velocity of 6,700 meters per year in 1985 to 5,700 meters per year in 1992, where it remained constant until 1997. But by 2000, the glacier had sped up to 9,400 meters per year, topping out with the last measurement in spring 2003 at 12,600 meters per year. Similarly, the glacier began thinning by as much as 15 meters (49 feet) a year just as its velocity began to increase between 1997 and 2003.

Along with increased rates of ice flow and thinning, the floating ice that extends from the mouth of the glacier into the ocean, called the ice tongue, began retreating in 2000, breaking up almost completely by May 2003."

EDIT

No link, subscription service.