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Iceberg twice as big as Manhattan breaks off of glacier

July 23, 2012

On Monday, July 16, NASA satellites showed that an iceberg twice the size of Manhattan broke off Greenland’s Petermann Glacier, one of the two largest glaciers left in Greenland, and this is not the first time it has happened. Two years ago, another ice island four times the size of Manhattan broke off from the same glacier.

One of the only memorable moments in The Day After Tomorrow was the scene in which Dennis Quaid watches a huge shelf of ice crack down the center, creating an enormous crevasse. What appeared as an over-dramatized prophecy of the effects of global warming in 2004 might not look so far-fetched any more.

According to researchers at the University of Delaware who discovered the fracture, Greenland’s ice sheet as a whole is rapidly melting and reducing in size due to changing global air and water temperatures and the resulting changes in circulation patterns.

Evidence supports the claim that something unusual is happening to Greenland’s ice. Before 2010, the last time an ice island of similar size broke off from a glacier in the region was fifty years ago, in 1962, when the Ward Ice Shelf in Nunavut, Canada, calved a 230-square-mile island. Additionally, studies show that the air around Greenland has increased in temperature by a little over a tenth of a degree Celsius yearly since 1987.

Nevertheless, Andreas Muenchow, associate professor of physical ocean science and engineering at the University of Delaware, is hesitant to blame global warming for the ice islands just yet. “Northwest Greenland and northeast Canada are warming more than five times faster than the rest of the world,” Muenchow told University of Delaware’s UDaily, “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.”

Still, ice scientist Ted Scambos told Fox News that if the Petermann continues to lose ice and that ice begins to melt, something the ice islands have not yet done, it will most likely lead to an increase in sea levels.

This summer, the Canadian Coast Guard Ship Henry Larsen is scheduled to travel to the Nares Strait and the Petermann Fjord to recover moorings placed by UD in 2009, which might help to solve the mystery behind the dissolution of the Greenland glacier. This data will provide scientists with ocean temperature, current, salinity, and ice thickness data from 2009 to 2012, including during the period when the 2010 ice island passed directly over the instruments. The moorings recorded data at a better than hourly rate, providing scientists with a detailed look at the patterns of the ocean in the area, in addition to the data collected from 2003 to 2009.

In the meantime, scientists expect that this new ice island will follow the same path as the one from 2010, which broke apart and scattered north and west and last year began to land in Newfoundland.