Warming May Curb Hurricane Landfalls in U.S.

The warming of the world's oceans may reduce the number of Atlantic hurricanes that make landfall in America, government researchers found.

Scientists at the National Oceanic and Atmospheric Administration analyzed Atlantic storms between 1854 and 2006. They found that higher ocean temperatures increase the vertical wind shear of a system, or the rate at which wind speeds vary with altitude, NOAA said in a statement on its Web site. That, in turn, correlated with a decrease in the number of storms that strike land.

"We found a gentle decrease in the trend of U.S. land-falling hurricanes when the global ocean is warmed up," an oceanographer at the center, Chunzai Wang, said in the statement. "This trend coincides with an increase in vertical wind shear over the tropical North Atlantic and the Gulf of Mexico." The study, which appeared yesterday in the journal Geophysical Research Letters, may influence future predictions of how global warming will affect America. Scientists with the U.N. Intergovernmental Panel on Climate Change said last year that rising temperatures will cause storms to intensify. Hurricane Katrina, which devastated New Orleans in 2005, caused more than $41.1 billion in insured damage.

The NOAA scientists found that warmer waters in the Pacific and Indian oceans help to increase vertical shear in Atlantic hurricanes, suppressing their activity and reducing the number of landfalling storms.