Melting East Antarctic ice sheet may cause global sea level rise

New York, Dec 18 (IANS) The East Antarctic ice sheet -- one of the two large ice sheets in Antarctica and the largest on the entire planet -- may contribute substantially to global sea level rise, finds a study.

The East Antarctic ice sheet, with more than 12,000 feet thick ice in many places, was thought to be among the most stable, not gaining or losing mass even as ice sheets in West Antarctica and Greenland are shrinking.

However, the findings showed that the ice sheet has a long history of expanding and shrinking.

The study, based on the first-ever oceanographic survey of East Antarctica's Sabrina Coast -- revealed that the glaciers in this region may be particularly susceptible to climate change.

This is because they flow from the Aurora Basin which has been stable only for the past few million years, and if the ice sheet in the Basin melted, global sea levels would rise more than 3-5 meters (10-15 feet).

"It turns out that for much of the East Antarctic Ice Sheet's history, it was not the commonly perceived large stable ice sheet with only minor changes in size over millions of years," said Sean Gulick, Professor at the University of Texas - Austin.

"Rather, we have evidence for a very dynamic ice sheet that grew and shrank significantly between glacial and interglacial periods. There were also often long intervals of open water along the Sabrina Coast, with limited glacial influence," Gulick added.

For the study, published in the journal Nature, the team deployed marine seismic technology from the back of an ice breaker near Antarctica's Sabrina Coast.

The equipment captured images of the seafloor, including geological formations created by the ice sheet, allowing scientists to reconstruct how glaciers in the area have advanced and retreated over the past 50 million years.

According to data, ice advanced from the Aurora Basin and retreated back again at least 11 times during the first 20 million years of the ice sheet's history.