Global Science Report is a weekly feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”
Come the cold season, whenever there is some type of strong storm system near the U.S. Eastern Seaboard—be it a Nor’easter, a blizzard, or ex-hurricane Sandy—you don’t have to look very hard to find someone who will tell you that this weather is “consistent with” expectations of climate change resulting from human greenhouse gas emissions. The worse the storm, the more “consistent” it becomes.
The complete collection of climate science describes just how complex the physical processes are governing such storm systems. Teasing out any anthropogenic influence, including even the direction of any influence, is darn near impossible. Claims to the contrary are usually based on a highly selective assessment of the science or the data.
A case in point:
The latest en vogue explanation linking human greenhouse gas emissions to strong winter-season East Coast storms involves changes in the characteristics of the jet stream—a river of fast moving air in the atmosphere that influences both the strength and the forward speed of extratropical storm systems. A prominent (in the media, anyway) research study last year by Rutgers’s Jennifer Francis and University of Wisconsin’s Stephen Vavrus suggests that the declining temperature difference between the Arctic and the lower latitudes (adding greenhouse gases into the atmosphere warms colder, drier regions more so than warmer, wetter ones—with the notable exception of Antarctica) has led to changes in the jet stream which result in slower moving, and potentially stronger East Coast winter storm systems.