Why the Arctic waters are reluctant to freeze

An exceptionally rapid melt this summer has led to unusually high water temperatures in the Arctic Sea, slowing the progress of fresh ice formation

Residents of the Alaskan city of Barrow (due to change its name to Utqiaġvik on 1 December) would normally be looking out across a frozen harbour by now, but this year the sea is reluctant to freeze.

Barrow’s average temperature for October 2016 was a balmy -1C, significantly warmer than the long-term average of around -8C. And over the North Pole the air has been a full 10C warmer than average of late.

Related: How warm seas powered two major hurricanes