Record Arctic Air Temperatures Are Wreaking Havoc on Walruses and Everything Else in the Region

These days, the Arctic is warming faster than anywhere else on earth. Air temperatures over the Arctic have risen more than 5 degrees Fahrenheit since records began in 1900, and were fully 2.3 degrees Fahrenheit above average this last year, making 2015 the hottest air temperature year in the Arctic ever recorded, according to this year's peer-reviewed "report card" on the region, put out by the U.S. National Oceanic and Atmospheric Administration in collaboration with 70 authors from 10 countries.

In the Arctic summer, the sun now heats open waters previously covered by ice. Land that used to be covered in reflective snow is now bare and sun-absorbent, which means it heats faster, too. June, for example, had the second-lowest snow cover for that month on record. This is not an isolated event: Every decade since 1979, the amount of Arctic land covered by snow in June has declined 18 percent, according to NOAA.

Sea ice in the Arctic fluctuates with the seasons, and in 2015, that fluctuation was particularly extreme: The minimum extent of the ice, when it is at its most melted each year, was 29 percent less than the 1981-2010 average. The maximum sea ice extent, when the most water in the Arctic is refrozen in winter, was the lowest on record.

But one of the most important measures of climatic change in the Arctic is how much ice manages to stay frozen over the summer months. This "old ice," which has lasted four years or more, is thick and stable, and in 1985 accounted for 20 percent of the ice pack. In 2015, it accounted for just 3 percent.

This is critically bad for animals that rely on sea ice to mate and give birth to their young. Walruses, for example, have been photographed teeming in large groups on land in recent years—NOAA says this is because they usually haul themselves out of the water and onto sea ice to mate and find shelter from storms. Now, NOAA says walruses are forced to travel much farther from their food sources to find land. As a result, they are ending up clumping together on the nearest patches of land in groups of tens of thousands, creating "problems such as overcrowding which has led to stampedes that have killed calves," NOAA writes.

The Greenland Ice Sheet, meanwhile, was in bad shape this year. For the first time since 2012, when researchers were astonished at the "exceptional" rate of melt that year, melting occurred on more than 50 percent of the ice sheet, and the melt season lasted 30 to 40 days longer than average.

"If the Greenland Ice Sheet were to melt away completely, ocean level would rise roughly 23 feet," NOAA notes in a press release. "So scientists have good reason to watch Greenland melt closely."