September 11, 2009

How Will Greenland’s Glacier Melt Change Sea Levels?

Scientists are trying to determine what occurred in Greenland's history to cause its glaciers to rapidly melt, and what implications it might have for the earth's future in light of looming global warming.

In 2005, scientists noticed that Greenland's Helheim Glacier had nearly doubled in speed as it moved through a river at a pace of 100 feet per day.

The rapid movement caught researchers by surprise and sparked concerns that it could be a sign of a massive melting of the Greenland's ice sheet to come.

"It does seem that the very rapid speeds were only sustained for a short period of time, although none of these glaciers have returned to the 'normal' flow speeds yet," Gordon Hamilton, a glaciologist from the University of Maine, told the Associated Press.

A melting of the massive two-mile-thick ice sheet could result in a global sea level increase of 20 feet.

Now scientists are trying to recover information that could provide clues as to why Greenland's glaciers sped up five years ago as the world confronts the dangers of global warming.

"This is like medical science in the 15th century," David Holland, director of the Center for Atmosphere Ocean Science at New York University, told the AP. "It's going to take a while to find out what's going on with the patient here."

Researchers told the AP that the Greenland ice sheet is receding at a pace of about 7 billion cubic feet each year.

Scientists are beginning to gain better insight at how Greenland's glaciers began to speed up, but they are still unsure about whether or not it can be attributed to natural processes or to human impact.

Scientists lean toward explaining that the occurrence was caused by a warmer ocean rather than warmer air.

Holland told the AP that warmer ocean water had reached the edge of the Sermeq Kujalleq, western Greenland's biggest glacier.

"We've had a confirmation that the waters are really coming up to the glacier," said Fiamma Stranneo, of the Woods Hole Oceanographic Institution in Massachusetts. "This is the first time that we've seen it in these southeast glacial fjords."

Last month, Stranneo led a team of researchers to study the temperature of the Sermilik fjord.

Researchers are trying to gather as much information as possible, as soon as possible, in order to meet a December deadline when the world's leaders are expected to meet in Copenhagen to discuss a new agreement to replace Kyoto Protocol, which will expire in 2012.

The Intergovernmental Panel on Climate Change's 2007 report estimated that sea levels could rise by 7 to 24 inches, but the report fails to take the Greenland melt into account.

Some researchers estimate that the addition of melting glaciers in Antarctica and Greenland could double to estimates projected by the IPCC.

"It doesn't sound like a lot, but it's an important difference by the way you sort of deal with that issue," Hamilton told the AP.

"How you engineer for a sea level rise of 30 centimeters is quite different as to how you would ... deal with a sea level rise of 1 meter."


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