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Differences in everything from sea ice to permafrost show the Arctic climate is changing even more rapidly than scientists had predicted, says a new summary of the most recent research.
The report, produced for the World Wildlife Fund and presented this week to the Arctic Council, adds that there could be factors contributing to climate change that were not even considered until recently.
"What we see out there happening is already a much stronger response than any of the computer models have predicted," said the lead author, climatologist Martin Sommerkorn. "There is a huge global significance to what happens in the Arctic."
The Arctic is a long way from where most humans live, but that doesn't mean it doesn't affect them, he said.
The report was compiled from papers published since the 2005 Arctic Climate Impact Assessment. It also contains research not considered by the 2007 United Nations International Panel on Climate Change.
Even those predictions may now be too conservative.
While the UN panel, which won a Nobel Prize for its work, predicted an ice-free Arctic by 2100, new measurements from the field suggest ice-cover shrinkage is actually 30 years ahead of that.
New models that take into account factors such as the increased absorption of the sun's heat by open water suggest the summer ice pack could be gone in five to 32 years.
The vast Greenland ice cap is also thought to be shrinking more quickly than anticipated.
"We don't have enough knowledge to be able to predict the future of the Greenland ice cap with any confidence," said Dr. Sommerkorn, who was speaking from Svolvaer, Norway. "But there are quite substantial scientific papers that show this immense ice loss in the last couple years."
Scientists now believe water melting off the cap is raising global sea levels by half a millimetre a year, five times the UN panel's estimate. The panel said sea levels would rise by a maximum of 59 centimetres by the end of the century, but newer research suggests the maximum is between 140 and 160 cm.
Also disturbing is the discovery of vast reserves of greenhouse gases locked in permafrost around the globe. Scientists now estimate those carbon reserves are roughly equivalent to the amount already in the atmosphere.
The Arctic tundra currently stores slightly more carbon than it emits, but that could change quickly with widespread permafrost melting. So far, there is only local evidence of that melt. But a paper in the journal Science released yesterday concludes that human activities are at least partly responsible for increased precipitation in the Arctic.
