Wednesday, February 10, 2010

Another Blizzard: What Happened to Global Warming?

Quite a good piece from Time. Most of the media have missed the “extreme weather” angle of climate change.

A pedestrian crosses Fuller Place in Brooklyn, New York. Mary Altaffer / AP

By Bryan Walsh
Wednesday, Feb. 10, 2010

As the blizzard-bound residents of the mid-Atlantic region get ready to dig themselves out of the third major storm of the season, they may stop to wonder two things: Why haven't we bothered to invest in a snow blower, and what happened to climate change? After all, it stands to reason that if the world is getting warmer — and the past decade was the hottest on record — major snowstorms should become a thing of the past, like PalmPilots and majority rule in the Senate. Certainly that's what the Virginia state Republican Party thinks: the GOP aired an ad last weekend that attacked two Democratic members of Congress for supporting the 2009 carbon-cap-and-trade bill, using the recent storms to cast doubt on global warming. (See pictures of the massive blizzard in Washington, D.C.)

Brace yourselves now — this may be a case of politicians twisting the facts. There is some evidence that climate change could in fact make such massive snowstorms more common, even as the world continues to warm. As the meteorologist Jeff Masters points out in his excellent blog at Weather Underground, the two major storms that hit Philadelphia, Baltimore and Washington, D.C., this winter — in December and during the first weekend of February — are already among the 10 heaviest snowfalls those cities have ever recorded. The chance of that happening in the same winter is incredibly unlikely.

But there have been hints that it was coming. The 2009 U.S. Climate Impacts Report found that large-scale cold-weather storm systems have gradually tracked to the north in the U.S. over the past 50 years. While the frequency of storms in the middle latitudes has decreased as the climate has warmed, the intensity of those storms has increased. That's in part because of global warming — hotter air can hold more moisture, so when a storm gathers it can unleash massive amounts of snow. Colder air, by contrast, is drier; if we were in a truly vicious cold snap, like the one that occurred over much of the East Coast during parts of January, we would be unlikely to see heavy snowfall. (See pictures of the effects of global warming.)

Climate models also suggest that while global warming may not make hurricanes more common, it could well intensify the storms that do occur and make them more destructive. …

Another Blizzard: What Happened to Global Warming?

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