For the first time since records began, the main nursery of Arctic sea ice in Siberia has yet to start freezing in late October.
The delayed annual freeze in the Laptev Sea has been caused by freakishly protracted warmth in northern Russia and the intrusion of Atlantic waters, say climate scientists who warn of possible knock-on effects across the polar region.
Ocean temperatures in the area recently climbed to more than 5C above average, following a record breaking heatwave and the unusually early decline of last winter’s sea ice.
The trapped heat takes a long time to dissipate into the atmosphere, even at this time of the year when the sun creeps above the horizon for little more than an hour or two each day.
Graphs of sea-ice extent in the Laptev Sea, which usually show a healthy seasonal pulse, appear to have flat-lined. As a result, there is a record amount of open sea in the Arctic.