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Warming & Winter

January 30, 2012

Arctic warming may actually be keeping winters cold for now, while raising temperatures in the other three seasons.

Transcript

BOB HIRSHON (host):

Wicked winters and warming.  I’m Bob Hirshon and this is Science Update.

Global warming may actually be keeping winters cold, at least for now.  This according to climatologist Judah Cohen, of the Massachusetts company Atmospheric and Environmental Research.  His team found that spring, summer and fall in the in the Northern Hemisphere have gotten steadily warmer recently, but winters haven’t.  One reason may lie in the warming Arctic autumns, where the warmer air can hold more moisture, and shrinking ice caps expose more seawater to evaporation.  The upshot:

JUDAH COHEN:

There’s been this statistically significant increasing trend in snow cover across Eurasia in the fall.  And the key month is October.

HIRSHON:

That snow, in turn, affects atmospheric patterns, pushing more cold air into the mid-latitudes during the winter.  Cohen notes that all this could break down when it gets too warm for those early snows to fall.  I’m Bob Hirshon for AAAS, the Science Society.