The Arctic sea ice is unlikely to shrink below last year's record low this year in a reprieve from the worst predictions of climate change even though new evidence confirms a long-term thaw is under way, experts said.
The 2007 record raised worries of a melt that could leave the North Pole ice-free this year, threaten indigenous hunters and thaw ice vital for creatures such as polar bears. It would also help open the Arctic to shipping and oil and gas firms.
"Most likely there will not be a new record minimum ice year in the Arctic this September," said Ola M. Johannessen of the Nansen Environmental and Remote Sensing Centre in west Norway.
The Arctic sea ice area reaches an annual summer low in September but is about one million square kilometres bigger than at the same time in late July 2007 at about six million square kilometres, an area almost as big as Australia.
It is still far smaller than the average of recent decades.
"It's looking rather unlikely that we will beat the record sea ice minimum of 2007," said Mark Serreze, a senior research fellow at the US National Snow and Ice Data Centre (NSIDC), adding there could still be surprises.
"The North Pole is likely to be safe for at least this year," he said. The NSIDC had suggested in May that it was "quite possible" that the North Pole could be ice-free this year.
"The basic reason is that while last summer saw an ideal atmospheric pattern for melting sea ice - essentially a "perfect storm" - the pattern so far this summer has been characterized by somewhat cooler conditions," he said. The 2007 low area of 4.13 million square kilometres shattered a 2005 record and was among factors adding pressure on governments to slow a build-up of greenhouse gases from factories, power plants and cars. Governments have agreed to negotiate a new climate treaty by the end of next year to succeed the UN's Kyoto Protocol.
Johannessen gave Reuters a hitherto unpublished study showing there was a 90 percent match between rising greenhouse gas emissions, mainly from use of fossil fuels, in recent decades and observations of a retreat of the ice.
"Ninety per cent ... of the decreasing sea-ice extent is empirically 'accounted for' by the increasing carbon dioxide in the atmosphere," he wrote in the study, to be published next month in a journal by the Chinese Academy of Sciences.
If the match continues to hold true, the annual average ice extent would be several million kilometres smaller by 2050 than predicted by the UN Climate Panel, which draws on the work of 2,500 scientists, it said.