An Australian researcher has suggested East Antarctica's giant Totten Glacier is partly unstable and could collapse, causing sea levels around the world to rise by more than two meters.

The Totten Glacier, one of the largest in the East Antarctic ice sheet, is increasingly becoming recognized as the most vulnerable glacier in the region.

East Antarctica, which has the world's largest concentration area of ice, was previously thought to be more secure than the smaller Western Antarctic area.

But in a new study, published by journal Nature on Thursday, climate scientists showed Totten Glacier wasn't as stable as first thought.

"While traditional models haven't suggested this glacier can collapse, more recent models have," said Dr Alan Aitken of the University of Western Australia, co-author of the study.

Based on modelling, Aitken identified that climate change could eventually claim up to one-third of the ice sheet if the earth's temperature continued its unprecedented rise.

"We confirm that collapse has happened in the past, and is likely to happen again if we pass a tipping point, which would occur if we had between three and six degrees of warming above present," he wrote.

The researchers looked at ice sheet activity, topography and sedimentary rocks to form the basis of their model.

Analyzing a 300-kilometer wide stretch of the glacier, they identified that one-third was relatively stable while two-thirds was unstable.

Of the 200-kilometer wide under-threat region, the scientists found half of that area could melt by the end of this century, or later, depending on climate change.

Melting of first 100-kilometer wide expanse of the ice would add about 90 centimeters to worldwide sea levels. But another 1.5 meters could be added to that figure, with the main section of the glacier left more expose in its absence.

However, Aitken said the issue could be avoided if humankind didn't let global warming rise by a further two degrees Celsius on current levels.

"We have in this system at least a little bit of breathing space to cope with some temperature increase because of that stable zone," he said.

"But if we exceed that point, then we're looking at a large additional contribution that could have been avoided if we stuck to our target." （Xinhua)