Wednesday, January 27, 2010

Arctic Ice Levels Off

Arctic sea ice leveled off a week ago.

Typically, Arctic ice extent slows down at the end of January and reaches a peak early in March, but with the unusual weather patterns of this winter, it may have nearly reached its peak already.

Most of the time, low pressure over the Arctic Ocean ensures that the cold air can’t leak out into the temperate zones of North America, Europe, and the Russian Far East. For most of this winter, though, Arctic air pressure has been higher, sending Arctic air as far south as Florida. The result has been much warmer air near the Arctic Circle, in places like Labrador. There was a period of a week earlier this month when I saw virtually the same temperatures in southern Labrador as in southern Pennsylvania. Today it is happening again, and this pattern may continue into next week. With daytime temperatures rising well above freezing at the edge of the Arctic ice, snow cover is melting away, and any sea ice that forms during the night will tend to melt during the day.

There is little immediate effect on the Arctic Ocean itself, but it’s easy to imagine that an early start to spring nearby could lead to a faster June melt on the Arctic Ocean.