East Antarctic Water Temperature not Higher

"The water under the ice shelf is very close to the freezing point," wrote Ole Anders Noest of the Norwegian Polar Institute in a statement after drilling through the Fimbul, which is 250-400m thick. "This situation seems to be stable, suggesting that melting under the ice shelf is not increasing," he wrote of the first drilling cores.

The findings, a rare piece of good news after worrying signs in recent years of polar warming, are only a small part of how Antarctica is responding to climate change. Antarctica holds enough water to raise world sea levels by 57m, so even tiny changes are a risk for low-lying coasts or cities such as Beijing and New York.

The Institute said that the water below the Fimbul was at a temperature of -2.05 degrees Celsius (salty water freezes at a slightly lower temperature than fresh water). This was slightly colder than estimates generated by a regional computer model for Antarctica, said Nalan Koc, head of the Norwegian Polar Institute's Center for Ice, Climate and Ecosystems. "The important thing is that we are now in a position to monitor the water beneath the ice shelf," she said. "If there is a warming in future we can tell."

Noc described how data collected could be included in a new report by the UN's Intergovernmental Panel on Climate Change, due in 2013-14. The last IPCC report in 2007 did not include models for sea temperature around the Fimbul Ice Shelf.

Experts have generally raised estimates for sea level rise. The United Nations spoke in late 2009 of a maximum 2m rise by 2100, up from 18-59cm estimated by the IPCC in 2007 which excluded any possible acceleration from Antarctica. The break-up of ice shelves does not in itself contribute to rising sea levels since the ice is already floating. However, melting ice shelves increase the risk that glaciers on land will flow faster toward the ocean if the shelves are removed.

At the Copenhagen climate summit last month, most nations agreed to limit any rise in world temperatures to below 2 degrees Celsius above pre-industrial times. They failed to set cuts in greenhouse gas emissions needed to achieve the goal, however.