The Arctic Ocean is on track to becoming ice-free in summers by 2040, while autumn and winter temperatures will be more than 12c higher in 2100 than they were at the end of the 20th century, claimed reports just released by the Arctic Council’s Arctic Monitoring and Assessment Programme.
The forecasts mark the end of the two-year US chairmanship of the eight-nation Council, and come two weeks ahead of the its ministerial meeting in Fairbanks, after which Finland will take over the chair for two years. The reports were released at a four-day Arctic science conference in Reston, Virginia, and outlined in a pair of teleconferences held on April 25th.
Jim Overland, NOAA oceanographer and co-author of the report Snow, Water, Ice and Permafrost in the Arctic (SWIPA), said that “the changes are cumulative, and so what we do in the next five years is really important on slowing down the changes that will happen in the next 30 or 40 years.” Changes are speeding up.
Since the previous SWIPA report in 2011, Arctic sea ice hit a record-low extent in 2012 and last year tied for the second-lowest level in the satellite record, noted the report. Between 2011 and 2014 Greenland lost ice at twice the rate observed from 2003 to 2008.
“The difference is the confidence in the results is much greater,” said Martin Forsius, chairman of the monitoring and assessment program and research professor at the Finnish Environmental Institute.
The latest SWIPA report used extrapolation of recent observations to come up with an estimate, Overland said. “It’s hard to pin down,” he said. “But this last summer, the ice was particularly thin and diffuse. So it’s not just the extent. The ice is changing with the pack.”