Researchers have discovered a valley underneath East Antarctica's most rapidly-changing glacier that delivers warm water to the base of the ice, causing significant melting. The intrusion of warm ocean water is accelerating melting and thinning of Totten Glacier, which at 65 kilometres long and 30 kilometres wide contains enough ice to raise global sea levels by 3.5 metres. The glacier is one of the major outlets for the East Antarctic Ice Sheet, which is the largest mass of ice on Earth and covers 98 percent of the continent.

Climate change is raising the temperature of the oceans, and sea levels are predicted to rise about one metre per century. Totten Glacier could represent a major component of this change.

The research is published today (Monday 16 March) in Nature Geoscience by scientists from Imperial College London and institutions in the US, Australia and France.

"It's only one glacier, but it's changing now and it is significant for sea levels globally," said study co-author Professor Martin Siegert, Co-Director of the Grantham Institute at Imperial College London. "The 3.5 metre rise may take several centuries to complete, but now the process has started it is likely irreversible. This is another example of how human-induced climate change could be triggering major changes with knock-on impacts that will be felt globally."