Rising Greenhouse Gases Could Prevent Weather Patterns Like the One Behind Sandy

As levels of greenhouse gases continue to rise, weather patterns like the one that steered Superstorm Sandy directly onto the East Coast's shores may become less frequent, according to a new study published in the Proceedings of the National Academy of Sciences.

Using state-of-the-art climate models, a team of researchers led by Elizabeth Barnes of Colorado State University's Department of Atmospheric Science are predicting a decrease in both the frequency and persistence of the westward flow that pushed Sandy onto land in October 2012.

As a result, the researchers conclude, atmospheric conditions will be less likely over time to send tropical storms crashing into the coast.

"Some recent research has implicated accelerated warming over the Arctic as the potential cause of the landfall of Sandy in 2012," Barnes said in a statement. "However, our study shows that, in the North Atlantic, the models project that temperature changes caused by rising levels of carbon dioxide and other gases will decrease the frequency of the occurrence of the circulation patterns that steered Sandy into the East Coast of the U.S."

The weather patterns that sent Sandy east were abnormal for two reasons, according to Barnes. First was the fact that the jet stream shifted toward the south and second was a "wave breaking" and blocking event that took place in the upper atmosphere that essentially halted the normal west-to-east wind. The two of these worked together to accelerate the storm toward the New Jersey coast: by the time Sandy made landfall, winds spanned more than 1,000 miles, resulting in widespread damage.

What the study does not address, notes co-author Lorenzo Polvani or Lamont-Doherty Earth Observatory in New York, is the probability of storms like Sandy occurring.

"These findings do not imply that there will be fewer events with the destructive power of Hurricane Sandy," Polvani said, "just that the models say it won't be because of increased atmospheric steering toward the coast. Future changes in the frequency of tropical cyclones remain an open question, and projected sea level rise would increase the risk of storm surges."