Warmer Winters Mean More Snow (On Average)

Waaaay back in December, world governments met in Copenhagen, in an attempt to form a deal to reduce greenhouse gas emissions. It failed miserably. Some were optimistic though, saying that American would pass a bill this year to control greenhouse gas emissions, and then the world could agree on a legally binding treaty later this year in Mexico.

I thought that was silly then, and I'm pretty sure everyone thinks its silly now. For a variety of reasons, Obama and the Democrats in Congress aren't going to pass a bill. But in case they didn't have enough reasons, the snowstorm in DC last week provided another one. Apparently, lots of people are saying that snow is a denial of global warming. They're using this as a further excuse to kill the bill.

It turns out that snow is much more likely to occur in a warming winter. As long as rain is still cold enough to freeze you'll have snow, but if it's not all that cold out, you're likely to have more of it (on average). It turns out warmer winters are wetter, and more wetness leads to more precipitation. See here, and here.

Obviously, any individual storm, or heat wave is not evidence for or against global warming. You have to look at the trends (they indicate warming). So it's an error to point to any single event, as those squawking about the snow storms are doing.

But their mistake is even worse than that, because in a warming world, we should expect bigger snow storms.