Aug 24, 2008

Is Greenland Turning Green?

A Section of the Ice Sheet Covering Much of Greenland

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New concerns from scientists over the ice sheets in the ironically named Greenland.

In northern Greenland, a part of the Arctic that had seemed immune from global warming, new satellite images show a growing giant crack and an 11-square-mile chunk of ice hemorrhaging off a major glacier, scientists said Thursday.

To put that into perspective, the piece that broke off is about half the size of Manhattan Island.

But the most alarming sign, according to Jason Box of the Byrd Polar Research Center at Ohio State University, is a huge 7-mile (11.3 kilometer) crack, seen above in the center right of the July 25 image, that has appeared farther back on the margin of the glacier.

The groove could create an imminent and even bigger breakup—up to a third of the ice field, he said in a statement.

"The pictures speak for themselves," Box told the Associated Press. "This crack is moving, and moving closer and closer to the front. It's just a matter of time till a much larger piece is going to break off … "

This is concerning for a couple of reasons. Firstly, if the glacier continues to calve, it will add to already rising water tables. Secondly, it could be an indicator of the growing impact of global warming.

The question that now faces scientists is: Are the fractures part of normal glacier stress or are they the beginning of the effects of global warming?

"It certainly is a major event," said NASA ice scientist Jay Zwally in a telephone interview from a conference on glaciers in Ireland. "It's a signal but we don't know what it means."

It is too early to say it is clearly global warming, Zwally said. Scientists don't like to attribute single events to global warming, but often say such events fit a pattern.

AP Photo/Byrd Polar Research Center

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