Yes, the middle Atlantic is getting socked with snow yet again. And, yes, here in New York City, we're just about to get wallopped as well. No, that doesn't mean that global warming is a sham, as plenty of delighted climate deniers have suggested through tweets and blog posts and signs atop of igloos.I like Juliet Elperin's take best in the Washington Post: "In this most wintry of Washington winters, those Al Gore jokes were only … a matter of time."But seriously, what's up? How to combat the all-too-obvious (and oh-so-unfortunate) headlines screaming that "Climate-change legislation buried under record snowfall in capital" or that the "Blizzard Rearranged Climate Change Announcement."First and foremost–and it can't be emphasized enough–weather is not climate. TIME's Bryan Walsh makes the point clearly: "it's a mistake to use any one storm - or even a season's worth of storms - to disprove climate change (or to prove it)…Weather is what will happen next weekend; climate is what will happen over the next decades and centuries."For the definitive look at why this actually isn't that surprising, check out meteorologist Dr. Jeff Masters' authoritative post "Heavy snowfall in a warming world." I'd recommend reading the whole thing if you expect to be engaging in any weather vs. climate debates, but here's the core nugget:
There are two requirements for a record snow storm:1) A near-record amount of moisture in the air (or a very slow moving storm).2) Temperatures cold enough for snow.It's not hard at all to get temperatures cold enough for snow in a world experiencing global warming. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, the globe warmed 0.74°C (1.3°F) over the past 100 years. There will still be colder than average winters in a world that is experiencing warming, with plenty of opportunities for snow. The more difficult ingredient for producing a record snowstorm is the requirement of near-record levels of moisture. Global warming theory predicts that global precipitation will increase, and that heavy precipitation events–the ones most likely to cause flash flooding–will also increase. This occurs because as the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970. This extra moisture in the air will tend to produce heavier snowstorms, assuming it is cold enough to snow.There was even a section in last year's U.S. Climate Impacts Report that speaks to this point directly, which concluded that "cold-season storm tracks are shifting northward and the strongest storms are likely to become stronger and more frequent." [Emphasis mine.] All that said, I can't really blame folks for piling on good ole' Al.Photo from Senator James Inhofe on Facebook
