The National Snow and Ice Data center based in Colorado report Arctic sea ice reached its maximum extent for the winter on March 15.
This year’s winter-time sea ice extent is the sixth lowest since the National Snow and Ice Data Center started keeping satellite records in 1979. Walt Meier is a research scientist at NSIDC. “In winter, we used to be about 16 million square kilometers, which is about double the lower 48 United States,” says Meier.
Based on this year’s satellite records, Meier says winter sea ice covered roughly 15.13 million square kilometers of the Arctic this year. That’s roughly ten times the size of the state of Alaska. It’s also equivalent to more than 337 billion football fields. “We’ve kind of lost about a couple million square kilometers,” he explains. “On the order of about 10 to 15 percent, so that’s kind of like the eastern sea board of the United states in terms of the ice loss.”
Meier says recent Arctic sea ice records show a more pronounced seasonal cycle. Data show more of the winter time sea ice that does exist is first-year ice, meaning it develops each winter but melts as temperatures warm in the spring and summer. “It used to be for example from Barrow Alaska, you’d see things open up, but you could take a boat out and reach the ice edge, but nowadays, the ice edge is much farther from the coast and the ocean is more exposed during the during the summer time.”
Sea ice acts as the Earth’s air conditioner. When it reflects sunlight, it cools the planet. “But now when we lose the ice cover,” says Meier. “The ocean is much darker than the ice. That absorbs all that solar energy that’s coming and that heats up the ocean. It’s like your air conditioning is running out of coolant. It’s not as efficient in terms of cooling the rest of the planet.”
NSIDC has measured the ten lowest winter sea ice extents in each of the last ten years, with the lowest ever measured in 2011. At the beginning of April, NSIDC scientists will release a detailed analysis of this year’s winter sea ice conditions in the Arctic.