Weather or Not?: Last Winter's Record Snow Driven by Short-Term Meteorologic Patterns, Not Long-Term Climate Change
Just six months ago residents of the eastern U.S. were shoveling themselves out of the snowiest winter ever--weather that prompted mockery of global warming among some people . Now, scientists have a new explanation for why such anomalous snowstorms can coexist with global warming: The storms were kicked up by the convergence of two natural, large-scale weather patterns.In order to better understand possible triggers of last year's media-dubbed " snowmaggedon ," a team of scientists from Columbia University's Lamont–Doherty Earth Observatory analyzed more than 50 years of snow data as well as measurements of atmospheric pressure and sea-surface temperatures. They found that a combination of El Niño (periodic sea-surface warming in the tropical Pacific Ocean) with an unusual period of decreased variability in atmospheric pressure across the North Atlantic (known as the North Atlantic oscillation , or NAO) frequently results in a pile-up of...