Scientists at the National Snow and Ice Data Center (NSIDC) and NASA said on Monday (March 28, 2016) that wintertime Arctic sea ice has reached a record low maximum extent, for the second year in a row. The record began with the advent of satellites in 1979, 37 years ago. At 5.6 million square miles (14.52 million square km), this year now has the lowest maximum extent in the satellite record.
This year’s maximum was slightly smaller than the previous record low maximum extent of 5.612 million square miles (14.54 million square kilometers), set last year.
The 13 smallest maximum extents on the satellite record have happened in the last 13 years.
This year’s maximum is 431,000 square miles (1,116,285 square km) below the 1981 to 2010 average maximum extent.
Notice we’re talking about wintertime maximum extent, which happens every year between February and April. Unlike Antarctica – which is a continent surrounded by ocean – the Arctic is a cap of frozen seawater, ringed by continents. Arctic sea ice melts during the spring and summer; scientists track a summertime minimum extent, too, and 2015’s was the 4th lowest in the satellite record. It grows back in the fall and winter.
The short animation below shows the Arctic sea ice freeze cycle from the last summertime minimum extent to March 24, when it reached 2016’s wintertime maximum.
NASA said in a statement:
The new record low follows record high temperatures in December, January and February around the globe and in the Arctic. The atmospheric warmth probably contributed to this lowest maximum extent, with air temperatures up to 10 degrees Fahrenheit above average at the edges of the ice pack where sea ice is thin, said Walt Meier, a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
The wind patterns in the Arctic during January and February were also unfavorable to ice growth because they brought warm air from the south and prevented expansion of the ice cover. But ultimately, what will likely play a bigger role in the future trend of Arctic maximum extents is warming ocean waters, Meier said.
Meier added that, because the ocean has also warmed up, the Arctic ice edge can’t expand as far south as it used to. He said:
Although the maximum reach of the sea ice can vary a lot each year depending on winter weather conditions, we’re seeing a significant downward trend, and that’s ultimately related to the warming atmosphere and oceans.
Since 1979, NASA said, that trend has led to a loss of 620,000 square miles (1,605,792 square km) of winter sea ice cover, an area more than twice the size of Texas.
NASA also said that 2016’s record low wintertime sea ice maximum extent won’t necessarily means a low summertime minimum extent:
Summer weather conditions have a larger impact than the extent of the winter maximum in the outcome of each year’s melt season; warm temperatures and summer storms make the ice melt fast, while if a summer is cool, the melt slows down.
Bottom line: In 2016, Arctic sea ice reached its lowest wintertime maximum extent in the 37-year satellite record. It’s slightly lower than the previous record, set last year. This year’s wintertime sea ice in the Arctic peaked on March 24 at 5.6 million square miles (14.52 million square km).