Global warming inhibits hurricanes, study finds

Some scientists say global warming intensifies storms.
MCCLATCHY NEWSPAPERS
MIAMI -- Now, the brighter side of global warming: It might not strengthen hurricanes after all, and it eventually could inhibit their development and growth.
Illustrating the bewildering complexity of the climate, a study scheduled for publication today found that global warming will strengthen a phenomenon called "wind shear" -- crosswinds that tear apart or substantially weaken hurricanes.
And that could counteract global warming's baking of the Atlantic Ocean, which some experts have predicted will grow so hot by the end of this century that it turbocharges hurricanes.
"Global warming is producing other changes in the environment besides a warming ocean, and these changes are acting to offset ocean temperatures," said Brian Soden, co-author of the new study and a climate scientist at the University of Miami's Rosenstiel School of Marine and Atmospheric Science.
Chris Landsea, the National Hurricane Center's science officer and an expert on global warming and hurricanes, said the study suggests that a warmer climate could make the Atlantic "more hostile to hurricanes."
Still, any changes will be very gradual, he and other scientists say. For now, we remain in a decades-long cycle of active hurricane development, they say, and last year's relatively benign season was the exception to the current rule.
The next six-month hurricane season begins June 1, and forecasters are predicting above-average activity.
Debate
The peer-reviewed study, in today's issue of Geophysical Research Letters, seemed certain to reignite one of the most heated debates in science: What effect, if any, does global warming have on hurricanes?
Some scientists say they have found evidence that global warming already has intensified the storms and will continue to do so, largely because hurricanes feed on warm water.
Others call that evidence sketchy and inconclusive, and they say any link between global warming and hurricanes is so tiny that it cannot be accurately measured.
The new study, also conducted by Gabriel Vecchi of the federal government's Geophysical Fluid Dynamics Laboratory in Princeton, N.J., examined 18 computerized forecast models that were tweaked to reflect a steadily warming climate.
Crosswinds
It found that one dramatic consequence of global warming will be the creation of stronger crosswinds over much of the tropical Atlantic, the primary breeding grounds of hurricanes.
The average intensity of those winds could increase by 10 percent to 15 percent by the end of the century, said Soden, who also helped write an influential warming study released in February by the Intergovernmental Panel on Climate Change.
The study also predicted increased wind shear in the eastern Pacific (near Mexico and Latin America), but less wind shear farther away in the Pacific, meaning that parts of Asia might experience more and stronger storms, called typhoons there.
The hurricane center's Landsea, who did not participate in the study, called it "a very important contribution to the understanding of how global warming is affecting hurricane activity."
Soden, Vecchi and Landsea emphasized that the new study does not alter the scientific consensus that global warming is occurring and humans are contributing to it.
"The fact that there may or may not be a connection between global warming and hurricanes shouldn't in any way undermine our concerns about global warming, which are very real," he said.