Climate change may or may not have helped generate the nor’easter lashing the East Coast this weekend. Such storms happen with some regularity, after all. But the amount of snow the storm called “Nemo” ultimately dumps, and the extent of flood damage it leaves in its wake, may well have ties to global warming, climate scientists suggested.
Michael Mann, a climatologist who directs the Earth System Science Center at Pennsylvania State University, compared a major storm like Nemo — or Hurricane Irene or Superstorm Sandy, for that matter — to a basketball slam-dunk with a lower net.
“If you take the basketball court and raise it a foot, you’re going to see more slam-dunks,” Mann said. “Not every dunk is due to raising the floor, but you’ll start seeing them happen more often then they ought to.”
The two key ingredients in a big snow: just cold-enough temperatures and a lot of moisture. Combine the chilled air converging on the East with the massive moisture coming from the Gulf of Mexico region and you’ve got the “perfect setup for a big storm,” Kevin Trenberth, of the Climate Analysis Section at the National Center for Atmospheric Research in Colorado, told The Huffington Post in an email.
As Trenberth explained, the ideal temperature for a blizzard is just below freezing — just cold enough to crystalize water into snow. Below that, the atmosphere’s ability to hold moisture to create those snowflakes drops by 4 percent for every one degree Fahrenheit fall in temperature.
“In the past, temperatures at this time of year would have been a lot below freezing,” Trenberth said. In other words, it’s been too cold to snow heavily. But that may become less of an obstacle for snow in the Northeast.
In addition to warming the air, climate change is adding moisture to it.
See also: Huffington Post: Boston Blizzard: Northeast Snowed In As ‘Nemo’ Barrels Through