Study: Warming may curb hurricanes

[JonathanBelles]

Associated Press
Published January 23, 2008

WASHINGTON - Global warming could reduce how many hurricanes hit the United States, according to a new federal study that clashes with other research.

The new study is the latest in a contentious scientific debate over how man-made global warming may affect the intensity and number of hurricanes.

In it, researchers link warming waters, especially in the Indian and Pacific oceans, to increased vertical wind shear in the Atlantic Ocean near the United States. Wind shear - a change in wind speed or direction - makes it hard for hurricanes to form, strengthen and stay alive.

So that means "global warming may decrease the likelihood of hurricanes making landfall in the United States," according to researchers at the National Oceanic and Atmospheric Administration's Miami Lab and the University of Miami.

With every degree Celsius that the oceans warm, the wind shear increases by up to 10 mph, weakening storm formation, said study author Chunzai Wang, a research oceanographer at NOAA. Winds forming over the Pacific and Indian oceans have global effects, much as El Nino does, he said.

Wang said he based his study on observations instead of computer models and records of landfall hurricanes through more than 100 years.

His study is to be published today in Geophysical Research Letters.

Critics said Wang's study is based on poor data that was rejected by scientists on the Nobel Prize-winning Intergovernmental Panel on Climate Change. They said that at times, only one in 10 North Atlantic hurricanes hit the U.S. coast, and the data reflect only a small percentage of storms around the globe.

Hurricanes hitting land "are not a reliable record" for how hurricanes have changed, said Kevin Trenberth, climate analysis chief for the National Center for Atmospheric Research in Boulder, Colo.

Trenberth is among those on the other side of a growing debate over global warming and hurricanes. Each side uses different sets of data and focuses on different details.

One group of climate scientists has linked increases in the strongest hurricanes - those with winds greater than 130 mph - in the past 35 years to global warming. The Intergovernmental Panel on Climate Change has said "more likely than not," man-made global warming has already increased the frequency of the most intense storms.

But hurricane researchers, especially scientists at NOAA's Miami Lab, have argued that the long-term data for all hurricanes show no such trend. And Wang's new research suggests just the opposite of the view that more intense hurricanes result from global warming. The Miami faction points to a statement by an international workshop on tropical cyclones that says "no firm conclusion can be made on this point."

Former National Hurricane Center director Max Mayfield said that regardless of which side turns out to be right, it only takes one storm to be deadly. So the key for residents of hurricane-prone areas, he said, is to be prepared for a storm "no matter what."

[Last modified January 23, 2008, 01:49:24]

http://www.sptimes.com/2008/01/23/World ... y_cu.shtml

[HURAKAN]

That's a possibility that I have already been thinking on. Could warmer waters mean an increase in wind shear? Maybe they are correct, I don't know. Also, the Sahara continues to expand. Would this mean an increase in the number and strenght of Dust Storms that move across the Atlantic inhibiting TC development? A lot of questions, very few answers, and a lot of confused people!!!

[RL3AO]

I've thought about that for a while. Even if it decreases numbers, when storms happen to hit an area with little shear, they will have much warmer waters. (Think Felix and Dean)

[cycloneye]

The opinions are diverse on this hot topic.What may happen in the next decades about Global Warming and hurricanes is not known,but what is important is that it only takes one storm to do the harm to a place and that is why the people have to be prepared every season.

[Cyclone1]

Honestly, I think hurricanes are so dependant on strictly local conditions I don't think global warming would have much of an effect on them at all.

In fact, I think this report may be providing a false sense of security.

Not saying global warming isn't real, just saying it doesn't affect hurricanes that much. Maybe I'm wrong.

And hurricanes don't by any means have to be in absolute perfect conditions to develop and sustain themselves. After Erin, I'm starting to think they don't even need water.

[Cyclenall]

Oh funny, the CBS Global Warming speical on last Sunday was talking about stronger hurricanes with GW. When will the other side be heard?

[RL3AO]

2035 Atlantic hurricane finishes up. During the season, six named storms formed with all six becoming category 5's.

[GCANE]

There may be some truth to the study; but there are more factors that need to be addressed.

From my observations, it appears, in general, that wind shear has been increasing around the peak of the traditional hurricane season.

However, the phenomena of a period of time where wind shear becomes minimal may be shifting in time during the season. Instead of coinciding with the peak SSTs; there may be two periods of minimal shear. One earlier in the season and one later. Witness invests and named storms in December.

As SSTs warm even further, there may be in fact two periods of time where the probability of tropical storm development reaches a peak; one in spring and then one in late fall. Since the one in late fall would have higher SSTs as compared to the one in spring; I would theorize that the peak probability would be higher as comapred to spring's.

[terstorm1012]

Did anyone catch the spat between Dr. Landsea and Dr. Holland on the radio the other day, down at the AMS conference?

Whatever the consensus is elsewhere, there's not really any on hurricanes, and this is the second study I've read that suggests what's written here, based on model runs.

[Frank2]

Yes, that's what I heard on TWC about a year ago - that increased shear due to warming ocean temps would inhibit hurricane growth...

Interesting - we'll see what happens...

[AJC3]

Did anyone catch the spat between Dr. Landsea and Dr. Holland on the radio the other day, down at the AMS conference?

Whatever the consensus is elsewhere, there's not really any on hurricanes, and this is the second study I've read that suggests what's written here, based on model runs.

Apparently, this did not go unnoticed by the media. It's mentioned here...

http://www.townhall.com/news/us/2008/01 ... s,_warming

Here are the links to NPR...

http://www.npr.org/templates/story/stor ... d=18292843
http://www.npr.org/templates/story/stor ... d=18369583

[Blown Away]

If you only look at the 2006-07 hurricane seasons, this story has alot of credibility. Shear ruled the Atlantic basin during the past 2 seasons and the overall #'s may have been slightly above average, but the majority of the systems were under heavy shear. We go from GW is causing the hurricane seasons to be more active (04-05) to GW will create more shear and less hurricanes following 2 mostly average seasons (06-07). All I know is it hard to tell if Winter is here in SFL, so it seems La Nina is here and it will be interesting to see if it will affect the 2008 season.

[KWT]

I seem to remember shear actually being below average last season though of couse that doesn't tell the full tale because the whole basin could be under high shear bar the Caribbean and gulf and it could still be a very dangerous season...all the shear last season seemed to be in the central atlantic region as we saw right in the heart of the tropical zone.