Antarctica region once thought stable suddenly `thawing fast`

Washington: A group of scientists has observed a sudden increase of ice loss in a previously stable region of Antarctica.

Using measurements of the elevation of the Antarctic ice sheet made by a suite of satellites, the team from the University of Bristol, UK found that the Southern Antarctic Peninsula showed no signs of change up to 2009.

Around 2009, multiple glaciers along a vast coastal expanse, measuring some 750km in length, suddenly started to shed ice into the ocean at a nearly constant rate of 60 cubic km, or about 55 trillion litres of water, each year.

This makes the region the second largest contributor to sea level rise in Antarctica and the ice loss shows no sign of waning.

Team leader Bert Wouters said that to date, the glaciers added roughly 300 cubic km of water to the ocean, which is the equivalent of the volume of nearly 350,000 Empire State Buildings combined.

By analysing roughly 5 years of the data, the researchers found that the ice surface of some of the glaciers is currently going down by as much as 4m each year.

The ice loss in the region is so large that it causes small changes in the gravity field of the Earth, which can be detected by another satellite mission, the Gravity Recovery and Climate Experiment (GRACE).

Wouters said that it appears that sometime around 2009, the ice shelf thinning and the subsurface melting of the glaciers passed a critical threshold which triggered the sudden ice loss. However, compared to other regions in Antarctica, the Southern Peninsula is rather understudied, exactly because it did not show any changes in the past, ironically.

The study is published in Science.