Global warming might decrease hurricane frequency

01/24/08 Seán Kinane
WMNF Drive-Time News Thursday | Listen to this entire show:

A new study concludes that the warming of the world’s oceans due to global climate change may actually decrease the number of hurricanes that make landfall in the United States.

In a paper published yesterday in the Journal of Geophysical Research Letters, Miami-based scientists Chunzai Wang and Sang-Ki Lee write that warming seas are associated with an increase in vertical wind shear in the region where Atlantic hurricanes develop.

According to the report, the increased wind shear associated with warm seas corresponds to a downward trend in frequency of hurricanes since the middle of the 19th century.

Jennifer Collins is an Assistant Professor in the Department of Geography at the University of South Florida.

“From what I understand of the article, it’s relating wind shear, although not localized wind shear, actually wind shear in other oceans and how the effects of that can affect what’s going on in the Atlantic Ocean. The Atlantic is linked to other areas through the complex nature of the atmosphere.”

Atlantic hurricane activity has increased in frequency and intensity since 1995, including the most active year on record, 1995. WMNF asked Collins whether the results of the study seem plausible.

“I think it’s a very interesting study, since many of the other studies have shown the opposite occurring, that actually you might get more hurricanes in a global warming environment or even that there be no change in hurricanes. So it’s certainly a very interesting study and one that’s concentrating on wind shear driving hurricanes whereas a lot of the other studies look at sea surface temperatures directly providing the fuel for the hurricanes.”

Warm seas usually increase the intensity of hurricanes, but Collins said there is still some controversy about whether the intensity of future hurricanes will be affected by climate change.

“There’s much literature out on the intensity of hurricanes and it’s huge debate in the world of the climate scientists because some people think it is affecting the intensity and other people think it doesn’t affect the intensity.”

Even though this study could be seen as good news regarding future hurricanes, Collins warns that Floridians should not become complacent.

“I think that people shouldn’t jump on just one paper alone. I think one article provides some evidence. And we have to weigh and balance that evidence with other research that’s been going on. So I don’t think the public or the insurance industry should just jump on anything and just run with it. I think they need to look at the whole picture and the research going on.”

Collins said that this year has the potential to be an active hurricane year.

“Well, just because this article is implying global warming is diminishing the number of hurricanes, I still think we should be cautious because we do know that we’re in a cycle that is indicating to stay around for the next 10, 15 years or so to be an active cycle with hurricanes. Not only that, but we’re in a La Niña phase, the opposite of the El Niño, and the La Niña phase tends to cause more hurricanes in the Atlantic and right now we are in that La Niña. We’ll have to see how that carries on into the summer.”

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