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Melting of Canadian Arctic ice sheet accelerating, study finds

April 13, 2010 |  2:14 pm

Belcher-glacier

The Devon Island ice cap, which sprawls over more than 5,500 square miles in the Arctic latitudes of Canada, has been shrinking at an increasing rate since 1985, an analysis of nearly 50 years of data concludes.

The melting, believed to have been caused by warmer summers, could affect shipping and overall sea levels, as more icebergs calf into the sea, according to the paper published in the March edition of Arctic, published by the University of Calgary's Arctic Institute of North America. Previous studies have noted a similar shrinking.

"We've been seeing more mass loss since 1985," said Sarah Boon, lead author on the paper and a geography professor at the University of Lethbridge.

Changes to Arctic ice and snow cover are not easily compensated, as the region experiences very little precipitation. Excessive warming is upsetting that balance, researchers warned. A recent remote-sensing study showed that the first decade of the 21st century included four unusually warm summers: 2001, 2005, 2007 and 2008, according to the data. 

"What we see during these warm summers is the extent of the melt is greater," Boon said.

The melt exposes darker ground that absorbs more solar radiation, helping to accelerate the melting at the cap's periphery. Calving from outlet glaciers has increased, potentially creating more obstacles to shipping, the authors said.

The paper adds to a growing volume of studies suggesting that man-made greenhouse gases are warming Earth, setting off widespread changes in climate.

Accelerated melting of the much larger Greenland ice sheet has been well chronicled.

-- Geoff Mohan

Photo: Belcher Glacier, a principal outlet glacier on the Devon Island ice cap. Credit: University of Alberta

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