From: National Oceanic And Atmospheric Administration.
Published May 20, 2008 09:37 AM

http://www.enn.com/top_stories/article/36568

A new model simulation of Atlantic hurricane activity for the last two decades of this century projects fewer hurricanes overall, but a slight increase in intensity for hurricanes that do occur. Hurricanes are also projected to have more intense rainfall, on average, in the future.

"This study adds more support to the consensus finding of the Intergovernmental Panel on ClimateChange and other reports that it is likely that hurricanes will gradually become more intense as theclimate continues to warm," said Tom Knutson, research meteorologist and lead author of the report. "It's a bit of a mixed picture in the Atlantic, because we're projecting fewer hurricanes overall."

...

Large-scale environmentalchanges in circulation, such as wind shear, as well as possibly moisture, are likely the dominant factors producing the reduced storm frequency. These results support recent research showing that the primary driver of the recent increase in Atlantic hurricane numbers was the warming of the tropical Atlantic relative to the other tropical basins.

These results are also consistent with a number of previous modeling and theoretical studies that have examined the influence of global warming from increasing greenhouse gases on hurricane intensity. An increase in hurricane intensities globally is assessed as "likely" in the Intergovernmental Panel on Climate Change Fourth Assessment Report issued in 2007.