It had to happen. In the midst of the record snowfall in the
East, some mainstream media outlet had to try to link this season’s
unusual weather events to global warming.
Time was the first news organization to take the plunge. It published such an article on February 10 — and that very day, Washington, D.C., broke its 1899 seasonal snow record of 54.5 inches with its third official blizzard of the winter. Today, the New York Times joined the party.
Like 2010, winter 1899 was characterized by multiple heavy snowstorms, especially in February. Sometimes the jet stream locks into a position where it is capable of creating such a string. As has been painfully obvious, this is one of those years.
Before 1942, D.C.’s official snow totals were taken downtown. The record since the measurement started being recorded at Reagan National Airport, set in 1996, has been eclipsed by ten inches this year.
The big January 1996 storm put down 17.1 inches at Reagan. The January 22, 1996, Newsweek cover featured a man disappearing in a whiteout with the headline “Blizzards, Floods, and Hurricanes: Blame Global Warming.” The cover story, written by the voluble science populist Sharon Begley, claimed that global warming allows more moisture into the air so that snowstorms can become bigger. Her go-to scientist was NASA’s James Hansen — who more recently became famous for calling coal drags to your local power plant “death trains” and advocating war-crime trials for the executives who daily force you to put gasoline in your car. (So clearly we should expect no hyperbole from that camp.)
This winter, D.C. has placed two storms in the top ten: The 18.0 inches that fell on February 5–6 ranks number four, and the 16.4 on December 18–19 is number eight. Time’s Bryan Walsh, who has a difficult time with the concept that improbable events are not impossible, thought this sufficiently bizarre to root online for any source that could be used to blame it on dreaded greenhouse gases. (Walsh found it in a semi-obscure 2003 study in the Journal of Climate, though he did not actually link to it in his article.)
And so the argument was trotted out again that mid-Atlantic storms can hold more moisture in a warmer world, and therefore can produce more snow. Anyone who would claim this surely does not understand the climatology of snow in Washington, D.C.
There are plenty of storms, usually up to 20 per winter, that are moist enough to produce snow but instead drop rain, or the unaesthetic combination of sleet and freezing rain that I call “sleeze.” Why no snow? Because there is simply not enough cold air available. Why so many near-snow events, like sleeze storms? Because there’s often almost enough cold air for snow.
To simplify things somewhat, snow requires that the temperature at 5,000 feet be at freezing or below. When a low-pressure system moves up the Atlantic seaboard, warm winds ride on top of it, raising the temperature to the point that it cannot support snow. In order to counter this, there usually has to be a replenishing supply of cold air from New England, which comes in the form of the high-pressure systems that often form ahead of the storm.
Scientists have known for a long time that the modest greenhouse effect we have experienced will have a disproportionate effect on these cold-air masses. So, thanks to climate change, the cold air that’s needed for Washington snow is increasingly hard to come by. Moisture is not the problem: Snowflakes fear warm air.
The fact of the matter is that global warming simply hasn’t done a darned thing to Washington’s snow. The planet was nearly a degree (Celsius) cooler in 1899, when the previous record was set. If you plot out year-to-year snow around here, you’ll see no trend whatsoever through the entire history.
But of course, there are those who insist that it snowed more when they were little. That’s partially a matter of physical perspective, as 20 inches of snow on the ground looks a lot bigger to a three-foot child than to a six-foot adult. It’s also a matter of lack of historical perspective. The three winters from 1977 through 1979 are the coldest in the entire U.S. record, and 1979 included the third-ranking snowstorm, the so-called President’s Day Mess.
Did I mention that the popular press back then, including Time and Newsweek, did not hesitate to blame the winters on the climatic bogeyman of that era — global cooling?