Oslo: A freak warming around the North Pole is sending a blast of Arctic cold over Europe in a sign of "wacky" weather that may happen more often with man-made global warming, scientists say.

On the northern tip of Greenland, the Cape Morris Jesup meteorological site has had a record-smashing 61 hours of temperatures above freezing so far in 2018, linked to a rare retreat of sea ice in the Arctic winter darkness.

"It's never been this extreme," said Ruth Mottram, a climate scientist at the Danish Meteorological Institute (DMI).

Warmth was coming into the Arctic both up from the Atlantic and through the Bering Strait, driving cold air south.

Around the entire Arctic region, temperatures are now about 20 degrees above normal, at minus 8 degrees, according to DMI calculations.