The Arctic is melting faster than expected and could contribute 2-3 feet more in global sea levels by 2100 than earlier thought, experts state in a report being presented to international officials on Wednesday. The report shatters predictions made four years ago by the authoritative U.N. climate change panel.
"The observed changes in sea ice on the Arctic Ocean, in the mass of the Greenland ice sheet and Arctic ice caps and glaciers over the past 10 years are dramatic and represent an obvious departure from the long-term patterns," the international Arctic Monitoring and Assessment Program says in its report.
The report compiles the latest science on how climate change has impacted the Arctic in the past six years.
Melting Arctic glaciers and ice caps are projected to help raise global sea levels by 35 to 63 inches by 2100, the program's scientists stated.
While the program noted the estimate was highly uncertain, the range was a sharp jump from a 2007 projection of 7 to 23 inches by the U.N.'s scientific panel on climate change. Those numbers did not include a possible acceleration of a thaw in polar regions.
A leading ice specialist, Richard Alley of Pennsylvania State University, who did not take part in the assessment, agreed that recent scientific estimates generally support its central finding.
A sea level rise of more than 3 feet this century "fits well within these estimates, and a somewhat higher value cannot be excluded," Alley said.
Such a rise — above most past scientific estimates — would add to threats to coasts from Bangladesh to Florida, low-lying Pacific islands and cities from London to Shanghai. It would also, for instance, raise costs of building tsunami barriers in Japan.
A summary of the key findings shows Arctic temperatures during that period were the highest since measurements began in 1880.
"The past six years have been the warmest period ever recorded in the Arctic," the report stated. The program is backed by the United States and seven other nations that make up the Arctic Council.
"In the future, global sea level is projected to rise by 0.9 meters (35 inches) to 1.6 meters (63 inches) by 2100 and the loss of ice from Arctic glaciers, ice caps and the Greenland ice sheet will make a substantial contribution," it said. The rises were projected from 1990 levels.
"Arctic glaciers, ice caps and the Greenland ice sheet contributed over 40 percent of the global sea level rise of around 3 mm per year observed between 2003 and 2008," it said.
The report was to be unveiled at a meeting of Arctic Council officials on Wednesday. Foreign ministers from Arctic Council nations — the United States, Russia, Canada, Sweden, Finland, Denmark, Norway and Iceland — are due to meet in Greenland on May 12.
"It is worrying that the most recent science points to much higher sea level rise than we have been expecting until now," European Climate Commissioner Connie Hedegaard told Reuters.
U.N. talks on a global pact to combat climate change are making sluggish progress. The United Nations says national promises to limit greenhouse gas emissions, mainly from burning fossil fuels, are insufficient to avoid dangerous changes.
The new report, drawing on work by hundreds of experts, said there were signs that warming was accelerating.
"The increase in annual average temperature since 1980 has been twice as high over the Arctic as it has been over the rest of the world," the report said. Temperatures were higher than at any time in the past 2,000 years, it added.
As a result, the Arctic Ocean could be nearly ice free in summers within 30 to 40 years, earlier than projected by the U.N. climate panel, it stated.
As reflective ice and snow shrink, they expose ever bigger areas of darker water or soil. Those dark regions soak up ever more heat from the sun, in turn stoking a melt of the remaining ice and snow.
"There is evidence that two components of the Arctic cryosphere — snow and sea ice — are interacting with the climate system to accelerate warming," the report stated said.