Thursday, September 5, 2013

Climate Study Finds Superstorm Sandy Unrelated to Global Warming, Predicts Such Storms Will Be Less Frequent in the Future

I ran across an interesting article in the USA Today regarding the study a climate researcher did on Superstorm Sandy, formerly known as Hurricane Sandy:
The role that global warming played in the disaster became part of the debate in the aftermath of the storm, with Bloomberg BusinessWeek magazine blaring, "It's the Global Warming, Stupid," on its cover immediately afterward.

"A lot of speculation after Sandy was that its steering winds were some sort of 'new normal" caused by a warming climate, says climate scientist Elizabeth Barnes of Colorado State university in Fort Collins, lead author of the new study in Proceedings of the National Academy of Sciences.

The research seeks to answer part of the question by looking into whether Sandy-like steering winds look more or less likely by 2100.  "We wanted to test that idea, and what we have found is that steering winds actually look less frequent in the next century," Barnes says. 
[Superstorm Sandy] was driven by east-moving jet stream winds that were bottled up by two "blocking weather patterns over the Atlantic Ocean.  With the jet stream pushing Sandy out to sea blocked, westerly winds at lower altitudes essentially shoved Sandy ashore.

In the new study, Barnes and colleagues looked closely at the future of the Mid-Atlantic, examining the likelihood of Sandy's sheering weather recurring by 2100.

Overall the models showed the eastward-moving jet stream strengthening int he Mid-Atlantic and the weather-blocking patterns becoming less frequent in at least 17 of the 22 forecasts of the future.  All of that means more hurricanes headed out to the sea, not into the coast.

"My interpretation is that Sandy was a rare event, and this looks like a reasonable approach to say some of the mixture of conditions that led to it look less likely in the century ahead," says climate model expert Tom Knutson of the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory in Princeton, N.J. who was not part of the study.
The article then goes on to express a warning about misinterpreting the results:
Regardless of the steering winds, Barnes adds, the study says nothing about whether hurricanes will become more or less frequent because of global warming.
"That's another piece of the puzzle," she says.
Knutson though is a research meterologist who looked at the last 100 years of hurricane activity in the Atlantic and found out that such activity has been declining despite claims that global warming would increase hurricane activity.  I reported his research on my blog.

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