Arctic sea ice coverage appears headed for a record-low winter maximum this year, and the annual melt appears to be off to a very early start, according to information from the National Snow and Ice Data Center.
The maximum extent of 5.59 million square miles, reached Feb. 25, was lower than any other year's winter maximum and 6.35 percent lower than the 1981-2010 average, according to the Boulder-based center. Sea ice extent has trended down since that date; ice extent usually peaks around the middle of March and last year peaked on the spring equinox, March 21.
Scientists are waiting a couple of days before declaring that the year's maximum has been reached, but the recent decline is striking, said Mark Serreze, director of the National Snow and Ice Data Center.
"We're seeing that the maximum is going to be at or near a record low, unless something funny happens in the next two weeks, which it could," Serreze said Monday.
The decline isn't necessarily an indicator of an extraordinarily big summer melt-off, Serreze said.
The regions where sea ice is particularly low this winter – the Bering Sea and Russia's Sea of Okhotsk – are areas where ice normally melts out in summer anyway.
"It's not quite clear what the low extent starting out the melt season is going to portend for the health of the ice," he said.
Winter satellite measurements are not nearly as significant as those in the summer and fall, Serreze said. The satellite images show just the extent of the ice, not its age, thickness or strength, he pointed out. The best indication of ice health comes in September, after a season's melt, he said.
Still, this winter's freeze-up statistics are interesting, he said, especially as they come during a year when the jet stream has been moving in unusual ways, bringing cold and snowy weather to the U.S. East Coast and warm weather to Alaska and the U.S. West.
Serreze said he does not see evidence that reductions in sea ice strongly influence the jet stream, as is hypothesized by some climate scientists. But sea ice disappearance is probably one of many factors resulting in the meandering pattern that has brought unusual weather to wide regions, he said.
"What changes in sea ice can do is, essentially, load the dice," he said.
Arctic sea ice extent reached its a record low on Sept. 16, 2012, when it dwindled to 1.32 million square miles, the lowest coverage since satellite measurements began in 1979. Last year's seasonal low was 1.94 million square miles, significantly higher than in 2012 but still the sixth-lowest in the satellite record. The six lowest annual Arctic ice minimums have occurred in the last eight years.