More hurricanes as result of global warming?
Submitted by Martin on Wed, 08/01/2007 - 00:03
Just published research suggests that numbers of Atlantic hurricanes are rising, and part of this rise is due to global warming.
Been plenty of arguments re warming and hurricanes (major tropical cyclones; known as typhoons here in Hong Kong and other parts of Pacific/S China Sea).
But, has always seemed likely: hurricanes form over warm seas, so as seas warm, can expect more - and more intense - tropical cyclones.
Yes, also seen Johnny Chan, HK researcher, who has found that over the Pacific, it's important ot also consider winds/air currents that can destroy these storms before they form: and these too may increase with warming, cancelling out effect of warming seas. (Plus, tropical Pacific warmer than Atlantic; temps generally well above those needed to form trop cyclones, while Atlantic more typically around the threshold level, so warming there can have more of an effect. [this guff partly from answer I asked Prof Chan at a global warming workshop, plus from his talk])
But interesting, too, to see that S America (east coast) lately had it's first tropical storm. And, just a few weeks ago, Arabian Peninsula hit by strongest cyclone since record keeping began there in 1945. For the latter:
http://www.sciencedaily.com/releases/2007/06/070613070547.htm
Also, even been computer models suggesting hurricane force storms just might impact the Mediterranean should warming continue.
Back to the hurricane research; info on Scientific American site includes:
Quote:
Using records dating back to 1855, hurricane researchers say they have uncovered an ongoing rise in the number of Atlantic hurricanes that tracks the increase in sea surface temperature related to climate change. Critics of such a link argue that this trend is merely because of better observations since the dawn of the satellite era in the 1970s. But the authors of the new study say the conclusion is hard to dodge."Even if we take the extreme of these error estimates, we are left with a significant trend since 1890 and a significant trend in major hurricanes starting anytime before 1920," say atmospheric scientists Greg Holland of the National Center for Atmospheric Research in Boulder, Colo., and Peter Webster of the Georgia Institute of Technology in Atlanta.
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The experts agree that natural variability is largely to blame for the relative intensity of various hurricanes, but Holland and Webster note that the locations of such storms have changed. "As more storms form near the equator, they are experiencing much better conditions for intensification and they are experiencing these conditions for a much longer period," the pair note. And that means more numerous and stronger hurricanes in the foreseeable future, whether the forecast is from a computer model or a meteorologist's instincts.
Stronger Link Found between Hurricanes and Global Warming
A century's worth of records suggests that hurricanes are on the rise and a warming Atlantic is to blame
Comments
Less hurricanes with warming and wind shear?
I've seen that numbers of west Pacific typhoons may decrease with global warming - as wind shear increases, so it's harder for them to form. Now, first news I've noticed that maybe this will be true for Atlantic - albeit contentious.
Must still wonder if warmer seas will lead to more strong storms (ie, powerful trop cyclones) - ie once they start forming, tend to become powerful, maybe fast.
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.
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Critics say 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.
Study: Warming May Cut US Hurricane Hits
Increase in numbers of intense tropical cyclones?
Good article by Chris Mooney, who has written book apparent link between hurricane/tropical cyclone intensity and global warming. Uses current Hurricane Dean as starting point, and includes:
To be sure, there’s a counterargument here: Data wasn’t as good on hurricane intensity in previous eras as it is today, when our measuring equipment is better than ever. Stronger storms may well have existed in the past, but we were simply incapable of detecting their true strength.
This is a serious objection, although it’s hard to know precisely how serious. Nevertheless, the fact remains that if you look at the official records, Dean now fits in to a staggering hurricane decade. That’s highly suggestive, if not definitive. And this staggering decade has occurred in part because of anomalously warm ocean temperatures in the hurricane-prone regions. Many scientists question whether you can explain these warm anomalies without invoking global warming as at least part of the cause.
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according to my ongoing “Storm Pundit” count of mega-hurricanes, Dean is the 10th Category 4 or 5 tropical cyclone observed globally this year. [Mooney lists the storms]
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by my own count, there were 19 of these intense storms in 2006, 22 in 2005, and 23 in 2004. Hurricane specialist Jeff Masters says the long term average is 17 — in which case all of these years would be above it and we might indeed be looking at a trend.
Hurricane Dean: 1 Of 10 Most Intense Atlantic Hurricanes Ever Measured