Climate change to trigger rapid retreat of Antarctic glacier

Current rates of climate change could trigger instability in a major Antarctic glacier, ultimately leading to nearly three metre rise of the sea level, say researchers.

The scientists looked at the future of Totten glacier, a significant glacier in Antarctica that drains one of the world's largest areas of ice, on the East Antarctic Ice Sheet (EAIS).

By studying the history of Totten's advances and retreats, the researchers discovered that if climate change continues unabated, the glacier could cross a critical threshold within the next century, entering an irreversible period of very rapid retreat.

This would cause it to withdraw up to 300 kilometres inland in the following centuries and release vast quantities of water, contributing up to 2.9 metres to global sea-level rise.

"The evidence coming together is painting a picture of East Antarctica being much more vulnerable to a warming environment than we thought," said study co-author Martin Siegert, professor at Imperial College London.

"This is something we should worry about. Totten Glacier is losing ice now, and the warm ocean water that is causing this loss has the potential to also push the glacier back to an unstable place," Siegert noted.

The East Antarctic Ice Sheet is currently thought to be relatively stable in the face of global warming compared with the much smaller ice sheet in West Antarctica, but Totten Glacier is bucking the trend by losing substantial amounts of ice.

The new research revealed that Totten Glacier may be even more vulnerable than previously thought.

The findings were published in the journal Nature.

To uncover the history of Totten Glacier's movements, the team looked at the sedimentary rocks below the glacier using airborne geophysical surveys.

From the geological record, influenced by the erosion by ice above, they were able to understand the history of the glacier stretching back millions of years.

The researcehrs found that the glacier has retreated more quickly over certain 'unstable' regions in the past.

Based on this evidence, the scientists believe that when the glacier hits these regions again we will see the same pattern of rapid retreat.

--IANS

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