Earth

West Antarctic ice shelves tearing apart at the seams

Floating ice shelves of a critical portion of West Antarctica are steadily losing their grip on adjacent bay walls. This could amplify an already accelerating loss of ice to the sea. That’s according to a new satellite study in the Journal of Glaciology that examined nearly 40 years of satellite imagery.

Ice shelves.
Rifts along the northern shear margin of Pine Island Glacier 2011. Image credit: Credit: Michael Studinger, NASA's Operation IceBridge.

The study says that that the margins of the floating ice shelves in the eastern Amundsen Sea Embayment in West Antarctica are fracturing and retreating inland. And this is where they grip onto rocky bay walls or slower ice masses. As that grip continues to loosen, these already-thinning ice shelves will be even less able to hold back grounded ice upstream, say the scientists.

The research team consisted of glaciologists from University of Texas at Austin’s Institute for Geophysics (UTIG). They found that the extent of ice shelves in the Amundsen Sea Embayment changed substantially between the beginning of the satellite record, in 1972, and late 2011. These changes were especially rapid during the past decade. Joseph MacGregor is lead author of the study. He said:

Typically, the leading edge of an ice shelf moves forward steadily over time, retreating episodically when an iceberg calves off, but that is not what happened along the shear margins.

An iceberg “calves” when it breaks off and floats out to sea.

Bottom line: There’s a new satellite study in the Journal of Glaciology. It examined nearly 40 years of satellite imagery. The conclusion is that floating ice shelves of a critical portion of West Antarctica are steadily losing their grip on adjacent bay walls. The study suggests this could amplify an already accelerating loss of ice to the sea.

Read more from the Jackson School of Geosciences

Posted 
March 30, 2012
 in 
Earth

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