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| Earth on Mar 30, 2012

West Antarctic ice shelves tearing apart at the seams

Floating ice shelves in West Antarctica are losing their grip on adjacent bay walls, which could amplify an already accelerating loss of ice to the sea.

Floating ice shelves of a critical portion of West Antarctica are steadily losing their grip on adjacent bay walls, which 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.

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

What’s happening, says the study, is the the margins of the floating ice shelves in the eastern Amundsen Sea Embayment in West Antarctica – where they grip onto rocky bay walls or slower ice masses- are fracturing and retreating inland. 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.

Location of Amundsen Sea Embayment. Image credit: Jackson School of Geosciences

The research team, glaciologists from University of Texas at Austin’s Institute for Geophysics (UTIG), 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 is said to calve when it breaks off and floats out to sea.

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

Read more from the Jackson School of Geosciences