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.

Delayed freeze in Laptev Sea could have knock-on effects across polar region, scientists say.