Strongest Atlantic Hurricanes May Almost Double Under Global Warming

The strongest Atlantic hurricanes may almost double in frequency by the end of the century as the planet warms, U.S. scientists said Thursday in the journal Science.

Occurrence of the most destructive hurricanes may rise 81 percent over 80 years while the total number of storms, including weaker systems, is projected to drop by 28 percent, the researchers said. The net effect may be to increase property damage by 30 percent, Tom Knutson, a co-author of the study, said.

"There will be fewer storms, more of these more intense storms, and it works out to some increase in damage potential," said Knutson, a climate scientist at the National Oceanic and Atmospheric Administration. The 81 percent rise translates to about a doubling over a century, he said.

An area northeast of Cuba and east of Florida that includes the Bahamas may see the biggest surge in incidence of the strongest hurricanes, according to the research. The findings have implications for the multibillion-dollar tourism industries of Florida and the Bahamas and Gulf of Mexico oil operations.

Storms rated Category 4 or 5 on the five-step Saffir- Simpson scale, with winds of at least 131 miles an hour, are those that are projected to increase in frequency. Hurricane Katrina, which devastated New Orleans in 2005, was a Category 3 storm when it made landfall. Katrina caused about $81 billion of damage and killed 1,833 people, according to the U.S. National Hurricane Center.

The scientists assumed a rise in the average sea-surface temperature of the tropics of 3.1 degrees Fahrenheit due to global warming over the 80-year period, Knutson said. Warmer waters favor hurricane formation.

The total number of storms will decline because conditions in the area where they typically start are projected to be less favorable to cyclone formation, Knutson said. At the same time, those that do form and move out of that region will find the conditions are then more favorable for intensification, meaning the strongest hurricanes will become more frequent, he said.

The biggest increase in stronger storms was detected north of the 20 degrees north line of latitude that runs south of Cuba and through Mexico's Yucatan Peninsula, said Morris Bender, a colleague at NOAA of Knutson and lead author of the study..

Graphics included in the study show the area east of Florida that includes the Bahamas may get up to three more Category 4 and 5 storms per decade.

In the Gulf of Mexico, home to oil platforms and facilities, the change would rangedfrom an increase of one stronger storm per decade to a decrease of one, the study forecast.

Morales reported from London.