The Arctic Ocean will be an "open sea" almost entirely free from ice within a decade, newly-released data has indicated.
Ice cover during the summer months will have entirely disappeared within 20 years, but most of the decrease will happen before 2020, leaving the Arctic Ocean clear for marine transport.
The changes will mean the top of the Earth will appear blue rather than white when photographed from space and ships will have a new sea route north of Russia.
The Catlin Arctic Survey, completed earlier this year by a team led by explorer Pen Hadow, is the latest research into the condition of Arctic ice.
Drilling and observation figures obtained during a 450km route across the northern part of the Beaufort Sea suggest the area is almost entirely made up of young, "first-year" ice, whereas the region traditionally consists of older, thicker "multi-year" ice.
Peter Wadhams, Professor of Ocean Physics and head of the Polar Physics Group, has spearheaded the team analysing the results.
"The summer ice cover in the Arctic will completely vanish in 20 to 30 years time. There won't be any sea ice there at all," he said. "In much less time than that, the ice in summer will be shrinking back to this last bastion north of Greenland and Ellesmere Island, so within a decade we will see a largely ice-free Arctic Ocean in summer.
"It won't be very long before we have to start thinking of the Arctic as an open sea. Man has taken the lid off the northern end of his planet and we can't put that lid back on again.
"There will be a small enough area left that you can regard the Arctic Ocean as open as far as transport is concerned for instance
"You'll be able to sail across the Arctic Ocean from Bering Strait to the Atlantic without any hindrance."
PA