Saturday, September 5, 2015

Global Warming Causing Cold Winters? Goofy And Denialist Bait, But Maybe True

New research suggests that global warming might be contributing to such extreme cold winters that have cropped up in some spots in the Northern Hemisphere in recent years, including last winter in New England.

Warming wouldn't seem to cause cold spells at first glance. And I'm sure the climate change denialists would spout and steam about how ridiculous this seems.

But more and more research seems to be backing up this thesis.

New research indicates a warming Arctic contributes
to larger dips in the jet stream, meaning more intense cold
blasts in mid-latitudes  
A new study in Nature Geoscience, a peer-reviewed journal says rising temperatures in the Arctic are contributing to some nastier and nastier winters occasionally in parts of North America and Europe.

The Arctic is warming at a much faster rate than points further south. The warmer Arctic makes for bigger northward and southward bulges in the jet stream, that wavy river of upper level fast moving air that largely controls the speed, strength and direction of weather systems.

The Arctic is warmer than it was, but it's still pretty cold in the winter. The sharper, more persistent southward dips in the jet stream, ones that dip more south than they used to, bring repeated waves of bitter air into places like the United States and western Europe.

The latest research builds on previous work by other scientists, including Jennifer Francis, a climate scientist at Rutgers University, that generally reached the same conclusions.

Of course, other factors are at work, too, so there's no guarantee any one winter will be bitter. For instance, El Nino is going to be a big factor this winter. El Ninos sometimes help prevent some of these big dips in the jet stream.

That's just one example of how the warming Arctic doesn't always cause cold winters in parts of the Northern Hemisphere, but it can.

Of course, the concept of cold winters gets the warming denialists all riled up.

Last year, when it was cold, for instance, some guy named James Taylor wrote in Forbes how "ridiculous" it is for climate scientists to suggest climate change could have contributed cold waves and large snowstorms.

This research about the Arctic's influence on the jet stream is valuable, but it will give ammunition to the denialist echo chamber which seeks to discredit climate scientists through some odd leaps of logic.

Next time somebody tells global warming doesn't exist because it's cold outside your own window, just wave them off.

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