It was an unusual winter in Washington, D.C. While the city was buried beneath the area’s largest snowstorm in recorded history, AU students relished a week without classes and witnessed the collapse of the Mary Graydon Center canopy as it succumbed to the weight of over two feet of snow, falling to the ground with a resounding crash. Perhaps not surprisingly, many global warming skeptics seized the opportunity to question the reality of climate change, making earth-shattering observations of their own. Surveying the snowpocalyptic wasteland of the nation’s capital, these outspoken skeptics (several of whom work in this very city) insightfully concluded that the world is not, in fact, warming up.

Take, for example, Sen. Jim DeMint (R) of South Carolina. On Feb. 9, the senator used his Twitter page to proclaim, “It’s going to keep snowing in Washington, D.C. until Al Gore cries ‘uncle.’ ” Or take Sen. James Inhofe (R) of Oklahoma, whose family built an igloo next to the Capitol adorned with a sign reading “Al Gore’s new home.” Gotcha, Al!

Well actually, fellas, the joke is on you. To make assumptions about the global climate based on a single storm in Washington is unscientific and simply illogical. According to AU professor Keryn Gedan, who teaches a course called Sustainable Earth, “Even a scientist who is a climate change skeptic wouldn’t say that such a storm is evidence against global warming – scientists must look at the long-term trend.”

Clearly, Sen. Jim DeMint is no scientist. If he were, he would be aware that such an unprecedented storm is perfectly consistent with what climate experts have been predicting. While it is common for many skeptics to be suspicious of this so-called “science,” the explanation behind recent aberrant weather is actually pretty simple.

A skimming of the Intergovernmental Panel on Climate Change’s 2007 Summary for Policymakers (I can name at least two policymakers who didn’t read this) reveals several important truths. Fact: average global temperatures have been rising. Fact: average atmospheric water vapor content has been rising. Because warm air can hold more water vapor, higher temperatures have led to increased evaporation.

What does this mean for weather patterns? Well, higher levels of water vapor in the atmosphere are expected to lead to more frequent events of heavy precipitation. In general, climatologists expect to see more erratic and extreme weather. It shouldn’t be too surprising that – given a long stretch of adequately cold temperatures – these unprecedented levels of water vapor produced an unprecedented snowstorm.

The unusual nature of this storm is precisely why we should be concerned about climate change. By mid-February, Washington had the second-highest seasonal snowfall of any U.S. city. Yes, Washington, D.C., just ahead of Rochester, New York. This is not normal.

So while the skeptics continue tweeting their ignorance to the world and building igloos where there shouldn’t even be snow, the rest of us should be concerned about our climate becoming warmer and weirder. Or else, by the time scientists cry “I told you so,” it will be too late.