Friday, June 11, 2010

Warming in the Arctic to Cause Colder Winters

In an ironic twist, a new study shows that rapid warming in the Arctic will make the weather in Northern Europe and Eastern North America much colder.  This was the weather pattern that prevailed in December and January of the past winter. The map below, from NASA, shows that temperature were much higher (red) than normal in the high Arctic, while much lower (blue) in Eurasia and North America.

At the International Polar Year Science Conference, currently taking place in Oslo, Dr James Overland of NOAA presented a study that says that a warming of the arctic will have significant impact on winter weather in Europe, Asia, and North America.  In fact, Dr Overland said "The exceptional cold and snowy winter of 2009-2010 in Europe, eastern Asia and eastern North America is connected to unique physical processes in the Arctic."

The loss of Arctic sea ice has long been seen as one of the areas that will have major feedbacks on a changing climate.  However, so far as I know, the focus of worries about those feedback has been that a (darker colored) ice-free ocean would absorb more heat than the (lighter colored) ice does currently.  This would cause the Arctic to warm, and would prevent the re-building of ice.  According to Dr Overland, this is occuring, and that will cause the current warming to be permanent.  However, this is the first study I've seen that supposes any effects on global weather patterns of a warming Arctic, and it is disturbing. 

Last year, Time magazine ran an article "Is There a Climate-Change Tipping Point?" which said that before we hit a tipping point that the earth would see what was called 'squealing'.  I'll quote directly from the article:

In climate terms, squealing may involve increased variability of the weather — sudden shifts from hot temperatures to colder ones and back again. General instability ensues and, at some point, the center ceases to hold. "Before we reached a climate tipping point we'd expect to see lots of record heat and record cold," says Carpenter. "Every example of sudden climate change we've seen in the historical record was preceded by this sort of squealing."
These tipping points - which we won't know about unitl after they've passed - are scary.  Rapid, sustained changes in the climate are impossible to predict, and as I've said before, uncertainty should worry us.

Of course, the fact that global climate change could cause record levels of snowfall and cold is a level of complexity that will struggle to make it through the ADD political-media crowd.  No points for guessing who will build the next igloo on the Capitol lawn.  If it weren't so important, it would be funny that a symptom of a rapidly changing climate is being used as evidence that the climate isn't changing. 

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