On March 2 snowstorms hit the eastern seaboard, coinciding with a widely publicized protest against the coal industry in Washington DC . This garnered some attention, with Time noting the irony of people chanting about global warming while shivering in the cold and snow. One might wonder if a March snowstorm is inconsistent with a warming world.
But there is no inconsistency. Weather is not climate. One event does not a trend make.
Snow fell from Maine to South Carolina on March 2, delighting schoolchildren with snow days and snarling traffic and airports. Parts of the greater NY metropolitan area saw snowfalls exceeding a foot.
Is this unprecedented? Is this proof that the climate is not warming?
No and no. As discussed in The Journal News (Lower Hudson Valley) , snowstorms in March are common in the NY region, even April snowstorms are not unheard of. As IRI’s Tony Barnston noted,
The main thing about these weather events is that they’re random and unpredictable.
And if random and unpredictable doesn’t resonate for you, check out the temperature (red line) for the week starting on March 1 from Weather Underground for Westchester County, NY (KNYHAWTH1). Two days of sub 20F weather were followed by 60F on Saturday and Sunday. Chaos anyone?
At longer time scales, year to year variability still swamps the moderate temperature rise associated with global warming, as seen by the El Nino years of 1998 (warm) and 2008 (cool) .
Climate is not characterized by the weather in one place or one season. Climate is regional; it refers to time scales of several years. Natural variability associated with seasons and longer time scales is real and large. We experience weather from day to day but it is the sum of that weather that constitutes climate.
Attributing any given heat wave, hurricane or snowstorm as caused by climate change is not strictly possible. However the models consistently predict that in our warming world, we can expect fewer days of frost, shorter winters, warmer summer nights, and warmer summers. These trends are already underway, with repercussions for ecosystems and humans. It will get worse. But it doesn’t mean that we won’t still have snowstorms in March.