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Massive ice island breaks off from Greenland glacier

By Catholic Online (NEWS CONSORTIUM)
July 18th, 2012
Catholic Online (www.catholic.org)

A massive chunk of ice, twice the size of Manhattan has broken off from a Greenland glacier, a University of Delaware researcher says. The 59-square-mile iceberg is the second such substantial loss for the Petermann Glacier over the past two years, researcher Andreas Muenchow reports. An ice island four times the size of Manhattan was lost from the glacier in 2010.

LOS ANGELES, CA (Catholic Online) - "While the size is not as spectacular as it was in 2010, the fact that it follows so closely to the 2010 event brings the glacier's terminus to a location where it has not been for at least 150 years," Muenchow reported in a press release.

The 2010 calving was the largest iceberg recorded in the Arctic since 1962.

Taking more than a decade to occur, a passing satellite captured the calving on camera. The iceberg appeared to make the final break in less than two hours, as images from a polar NASA satellite demonstrate.

Scientists analyzing years-old satellite data from 2001 first noticed the rift in the glacier's floating forward edge, or ice shelf, several years ago. Scientists correctly predicted that the most recent iceberg would break away during the warm summer months of this year.

However, Muenchow says it's too early to blame global warming for the loss of Greenland ice.

"Northwest Greenland and northeast Canada are warming more than five times faster than the rest of the world," Muenchow says, "but the observed warming is not proof that the diminishing ice shelf is caused by this, because air temperatures have little effect on this glacier; ocean temperatures do, and our ocean temperature time series are only five to eight years long - too short to establish a robust warming signal."

The latest chunk of ice is expected to drift into the Nares Strait between Greenland and Canada, where it will break up into smaller icebergs, which could take a while. Fragments of the 2010 calving can still be found along the Canadian coast as far south as Labrador.

The Petermann Glacier finds its way through Greenland's ice sheet, and essentially serves as a slow-moving conveyor belt, moving ice from the middle of the ice-bound island to the sea, where it forms colossal, floating plains of ice that, from time to time, give birth to enormous icebergs. 

These floating ice plains also buttress up the glaciers that feed them, slowing their progress into the ocean. Research has revealed that when ice shelves weaken or collapse entirely, glaciers speed up, moving more ice off of land and into the ocean and raising global sea levels.

This week's iceberg birth has shrunk the Petermann Glaciers' ice shelf significantly, scientists say.

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