London: Arctic Sea could be ice free by the summer of 2015, a leading ocean expert in Britain has claimed. According to Prof Peter Wadhams of Cambridge University, the ice that forms over the Arctic sea is shrinking so rapidly that it may vanish altogether in four years' time, destroying the natural habitat of animals like polar bears.

The mass of ice between northern Russia, Canada and Greenland waxes and wanes with the seasons, currently reaching a minimum size of about four million square kilometres.

Most models, including the latest estimates by the Inter- governmental Panel on Climate Change (IPCC), track the decline in the area covered by ice in recent years to predict the rate at which it will deteriorate.

But citing research compiled by Dr Wieslaw Maslowski, a researcher from the American Naval Postgraduate School, Prof Wadhams said that such predictions failed to spot how quickly climate change is causing the ice to thin.

While the IPCC suggests the ice will remain in place until the 2030s, Dr Maslowski's study also takes into account the rate at which it is thinning and calculates that it will vanish much more quickly.

Dr Maslowski's model, along with his claim that the Arctic sea ice is in a "death spiral", were controversial but Prof Wadhams, a leading authority on the polar regions, said the calculations had him "pretty much persuaded."

Prof Wadhams said, "His (model) is the most extreme but he is also the best modeller around. It is really showing the fall-off in ice volume is so fast that it is going to bring us
to zero very quickly. 2015 is a very serious prediction and I think I'm pretty much persuaded that's when it'll happen."

The ice would come back the following winter but its absence in summer would encourage more shipping and oil exploration in the Arctic and could threaten native species, he added.

While polar bears hibernate on land in the winter, they move onto the ice in the spring to hunt.

Prof Wadhams said, "The obvious case that everybody points to is the polar bear, and that obviously would either become extinct or it could be that they will go back to hunting on land."