An ice scientist has claimed that the loss of Arctic ice is effectively doubling mankind's contribution to global warming.
According to Professor Peter Wadhams, white ice reflects more sunlight than open water thus acting like a parasol.
Melting of white Arctic ice, currently at its lowest level in recent history, is causing more absorption.
Wadhams calculates that this increased absorption of the sun's rays is "the equivalent of about 20 years of additional CO2 being added by man".
The Cambridge University expert says that the Arctic ice cap is "heading for oblivion".
In 1980, the Arctic ice in summer made up some 2 percent of the Earth's surface, but since then the ice has roughly halved in area, and the volume of ice has dropped to just a quarter of what it was.
"The volume of ice in the summer is only a quarter of what it was 30 years ago and that's really the prelude to this final collapse," the BBC quoted Wadhams as saying.
The polar ice cap acts as a giant parasol, reflecting sunlight back into the atmosphere in what is known as the albedo effect.
But white ice and snow reflect far more of the sun's energy than the open water that is replacing it as the ice melts.
Instead of being reflected away from the Earth, this energy is absorbed, and contributes to warming.
Wadhams added that parts of the Arctic Ocean are now as warm in summer as the North Sea is in winter.