Top hurricane scientist cools to global warming
New study suggests storm frequency, intensity may not substantially rise during next 2 centuries
One of the most vocal scientists in the field of hurricane prediction has backed away from his earlier certainty of a link between global warming and stronger hurricanes after developing a new forecasting technique that suggests a moderate increase – or even decline – in storm activity over the next 200 years.
Kerry Emanuel, a climate scientist at Massachusetts Institute of Technology, and his co-authors published their findings in the March issue of Bulletin of the American Meteorological Society.
"The results surprised me," Emanuel told the Houston Chronicle.
Emanuel's latest research tackled a problem facing hurricane prediction efforts based on climate models. Most such models, used to predict global atmospheric conditions for centuries in the future, are unable to detect individual tropical storms.
The new technique pioneered by Emanuel "downscales" the simulations by creating "seeds" of tropical systems – bits of computer code – throughout the climate model to see how they behave in terms of its global predictions.
Simulations conducted in the study satisfactorily reproduced past hurricane fluctuations, convincing the researchers it could be used for more accurate predictions.
Emanuel and his colleagues found reduction in the number of hurricanes around the world over the next two centuries with increases in intensity in some regions.
"The models are telling us something quite different from what nature seems to be telling us," Emanuel told DotEarth, the New York Times science blog.
"There are various interpretations possible, e.g. a) The big increase in hurricane power over the past 30 years or so may not have much to do with global warming, or b) The models are simply not faithfully reproducing what nature is doing. Hard to know which to believe yet.
Emanuel was among the first to publish his belief global warming was responsible for the increased number of tropical storms making U.S. landfall during the 2004 and 2005 season. Just three weeks before Hurricane Katrina struck New Orleans, Emanuel, in a paper published in Nature, wrote that a key measurement of the power dissipated by a storm during its lifetime had risen dramatically since the mid-1970s.
In the future, Emanuel concluded, 2005's hurricane activity would become the norm rather than the exception.
As WND reported, lawyer and environmentalist Robert Kennedy Jr. cited that study in blaming the Bush administration for the catastrophic damage caused by Katrina.
"The science is clear," wrote Kennedy, son of slain New York Sen. Robert F. Kennedy, in a commentary at HuffingtonPost.com. "This month, a study published in the journal Nature by a renowned MIT climatologist linked the increasing prevalence of destructive hurricanes to human-induced global warming."
The presumed global warming-hurricane link was used in promotions for Al Gore's "An Inconvenient Truth," with a satellite image of a hurricane emanating from a smokestack.
Emanuel "had the good fortune, or maybe the bad fortune, to publish when the world's attention was focused on hurricanes in 2005," Roger Pielke Jr., who studies science and policy at the University of Colorado, told the Chronicle. "Kerry's work was seized upon in the debate."
Now the debate may go in a different direction.
"The take-home message is that we've got a lot of work to do," Emanuel said of his latest findings. "There's still a lot of uncertainty in this problem. The bulk of the evidence is that hurricane power will go up, but in some places it will go down."
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