The meltdown in the Arctic is speeding up and as a result the North Pole could be ice-free by 2013 instead of in 60 years' time as earlier predicted, scientists have warned.

Within the Arctic circle there are 90 billion barrels of oil and vast quantities of natural gas waiting to be tapped, most of it offshore, the government-run US Geological Survey said.

The area north of the Arctic Circle has an estimated 90 billion barrels of recoverable oil, the US Geological Survey (USGS) has said.