

Ice extent across the Arctic Ocean reached its annual minimum about two weeks ago. At this point ice would normally be forming rapidly, especially in the center of the Arctic Ocean. However, ice coverage in the Central Arctic Basin, the largest part of the Arctic Ocean comprising around 4.5 million square kilometers, continues to decline puzzling climate scientists.

This region has never before experienced continued melting this late into fall. Even during the record-low years of 2007 and 2012 the center of the Arctic Ocean was freezing over rapidly by mid-October.

"In fact now ice extent in the Central Arctic Basin is second lowest for the day. Its slightly below the overall record year 2012. Only in the year 2007 there was less ice in the Central Arctic on this day of the year," says Lars Kaleschke from the Center of Marine and Atmospheric Research (ZMAW) at the University of Hamburg. About 500,000 square kilometers of ice coverage are missing – about the size of Sweden – compared to the previous five years.

What exactly this development means for Arctic sea ice later this winter remains unclear, but it’s another unsettling development in a region where climate change is happening at twice the rate of the rest of the world.

"It is still a bit too early to draw any conclusions for wintertime weather patterns in response to the current sea ice loss. However, Arctic climate change is happening now," says Zack Labe, climate scientists at the University of California, Irvine.