The Biggest Ice Shelf Could Collapse at Any Time

The Ross Ice Shelf on the Antarctica is the largest ice shelf (ice floating over open ocean) worldwide, several hundred meters thick and covering a surface roughly equal to that of France.

Recent research showed that this giant could break off from Antarctica without warning causing a dramatic rise in sea levels. Analysis of ice cores achieved by drilling the shelf will detail three million years of climate history, at the same time revealing clues as to what may happen in the future. Analysis of sea-floor cores near Scott Base points that the Ross Ice Shelf had broken in the past, at times, suddenly. A 83m core offers climate records spanning about 500,000 years.

The results of the sediments analysis reveal how this huge ice shelf could react faced to global warming. "If the past is any indication of the future, then the ice shelf will collapse," said Dr. Tim Naish, a sedimentologist with the Institute of Geological and Nuclear Sciences of New Zealand.

"If the ice shelf goes, then what about the West Antarctic Ice Sheet? What we've learnt from the Antarctic Peninsula is when once buttressing ice sheets go, the glaciers feeding them move faster and that's the thing that isn't so cheery."

Antarctica's ice keeps 90 % of the world's fresh water, with the West Antarctic Ice Sheet storing about 30 million cubic km. Scientists believe that Ross Ice Shelf collapse would rise sea levels between 5 to 17 m. "We're really getting everything we've dreamed of. What we're getting is a pretty detailed history of the ice shelf," he said. "You go from full glacial conditions to open ocean conditions very abruptly. It doesn't surprise us that much that the transition was dramatic."

The Larsen Ice Shelf collapse in 2002 had already proved that ice shelf can desintegrate "extremely quickly".

"Once dating of the sample was completed, researchers would be able to look at what the ice shelf was doing during periods when scientists knew from other evidence that it was 2degC to 4degC warmer than today," said Naish.