The Arctic’s Winter Sea Ice Barely Got Started This Year
Last December the world agreed to keep temperatures from rising more than 3.6 degrees Fahrenheit above pre–industrial revolution levels—before coal-fired power began to drive up atmospheric carbon.
That consensus appears to have come too late for the Arctic.
In February, land temperatures in many parts of the far north soared more than 7.2 degrees Fahrenheit higher than the average from 1951 to 1980, according to the National Snow & Ice Data Center in Boulder, Colorado. Over the central Arctic Ocean, air temperatures were 11 to 14 degrees higher than the 1981 to 2010 average, the agency reported.
The heat broke a regional high-temperature record set just one month earlier and led to a record-setting low in Arctic winter sea ice: 5.5 million square miles, nearly half a million square miles fewer than the 1981 to 2010 February average of about 5.9 million square miles.
The Arctic winter ice cap usually expands nonstop until early spring. But in mid-February the freeze stalled, said Julienne Stroeve, a senior scientist at the National Snow & Ice Data Center, and then resumed at a slow pace late in the month.
“A reporter I was talking to said she’s seeing open water in the Bering Strait, which is really unusual,” Stroeve said.
Natural drivers—such as the El Niño weather cycle over the Pacific—are partly responsible for the diminished sea ice, but Stroeve estimates that about 50 to 60 percent of observed ice loss is due to greenhouse gases.
In the European Arctic, areas north, northeast, and south of Svalbard, and north of Novaya Zemlya, are showing up as open water in satellite imaging, said ice physicist Sebastian Gerland of the Norwegian Polar Institute. "The median from 1981 to 2010 is substantially further in extent than the ice is now.”
Region-wide, “ice is getting less old in the Arctic,” said Gerland, who has been gathering ice thickness data for over two decades with underwater sonar instruments anchored in the Fram Strait, a passage between Greenland and Svalbard.
“The Fram Strait is the main exit route for ice from the Arctic Ocean,” he said, and over time, more of the ice passing over his sonar devices has become thin, first-year ice, rather than thicker multiyear ice.
Scientists have estimated that less than 5 percent of current Arctic sea ice is five or more years old, compared to about 20 percent in the 1990s.
These changes are putting Alaska Native hunters in danger, and changing the migratory patterns of the seal, walrus, and polar bear populations they hunt, said Austin Ahmasuk, a marine issues expert with Kawerak, Inc., a nonprofit that offers social and economic services to 20 Alaska Native communities in the Bering Strait region.
“Wintertime is considered the time when you can, historically, get to many places on the ice, on land, on frozen rivers, that are hard to get to in the summer time,” said Ahmasuk.
But when “ice is much thinner, it goes out earlier. Safe periods for travel are being impacted,” he said.
“In rural Alaska, hunting replaces the grocery store everywhere else,” Ahamsuk said. “We have this ancestral connection to ice. So do the animals. Many of the animals we hunt are adapted to an ice environment, and that environment is less than it was.”
This article has been revised to reflect the following correction:
Correction: March 3, 2016
An earlier version of this article misstated the ice-free areas of the eastern Arctic Ocean in February. They are north, northeast, and south of Svalbard and north of Novaya Zemlya and were assessed using satellite imaging data.