Although now is the time when the Arctic is supposed to be refreezing, scientists say sea ice there hit record low levels for November. In the crucial Barents Sea, the amount of floating ice decreased when it would be expected to grow.
Arctic sea ice extended for 9.1 million square kilometres. That's 800,000 square kilometres below the record set in 2006.
The National Snow and Ice Data Centre says it's the seventh month this year to set a record low.
"There's crazy stuff going on up there. It's bad," said Rutgers University marine scientist Jennifer Francis.
The data centre calculated that ice in the Barents Sea, just outside Norway, shrank by 50,000 square kilometres during what is supposed to be a cold month, but wasn't. That area is important because recent research links sea ice there to changes in extreme weather in lower latitudes, though scientists have not come to a consensus on that link yet.
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"Almost certainly there will be unusual weather events this winter," Francis said.
The sea ice reached levels not seen since satellites started to monitor the region in 1979. Some Arctic air was 10 degrees Celsius warmer than normal and seawater was 4 degrees above normal, preventing sea ice from forming. Data centre scientist Julienne Stroeve blamed natural weather patterns and man-made global warming.
