I don't think anyone can top this:
Lots of snow falling outside. This proves whatever I believe. — Dan Gardner (@dgardner) February 9, 2013
Now I read that as a clever rejoinder to all sides in the climate debate. But since we're already seeing stories that link global warming to the blizzard that has just struck the Northeast, let's focus on the side that is making the connection. First, some helpful background. A year ago, Kevin Trenberth, a climate scientist with the National Center for Atmospheric Research (NCAR), wrote an essay that I believe has deeply influenced, or at least, reinforced, what I call the new normal in the climate discourse. Trenberth:
Scientists are frequently asked about an event “Is it caused by climate change?” The answer is that no events are “caused by climate change” or global warming, but all events have a contribution. Moreover, a small shift in the mean can still lead to very large percentage changes in extremes. In reality the wrong question is being asked: the question is poorly posed and has no satisfactory answer. The answer is that all weather events are affected by climate change because the environment in which they occur is warmer and moister than it used to be.
The emphasis is his. I think it's hard to overstate how brilliant this is as a rhetorical framing device, for now we see that every major storm and severe weather event is discussed in the context of climate change. It's a tricky balancing act for journalists who aim to put big storms in such a context. Here's Bryan Walsh at Time on the recent blizzard:
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.