A new study indicates that a large ice sheet is at risk. Warm water from below is causing it to melt.
Scientists are predicting the disappearance of another vast ice shelf in Antarctica by the end of the century that will accelerate rising sea levels.
The Filchner-Ronne Ice Shelf fringing the Weddell Sea on the eastern side of Antarctica has so far not seen ice loss from global warming and much of the observation of melting has focused on the western side of the continent around the Amundsen Sea. But new research from the Alfred Wegener Institute for Polar and Marine Research in Germany says the 450,000-sq-km ice shelf is under threat.
"According to our calculations, this protective barrier will disintegrate by the end of this century," said Dr Harmut Hellmer, lead author of the study, published in the journal Nature this week.
The huge ice shelves that float on the seas fringing Antarctica provide a buffer against warming waters eating away at the base of the much larger glaciers behind them that sit on the land.
"Ice shelves are like corks in the bottles for the ice streams behind them," said Hellmer. "They reduce the ice flow.
"If, however, the ice shelves melt from below, they become so thin that the dragging surfaces become smaller and the ice behind them starts to move."