Global Warming Expected to Worsen Hurricanes

July 9, 2005 — -- In Florida, they know just how powerful hurricanes can be: Over the last year, they have been reminded more than they care to count.

But it could get even worse.

According to a recent study, hurricanes will become even more intense because of global warming -- the idea that greenhouse gases are heating the Earth's atmosphere and oceans.

"Those storms that do occur are going to have the potential to be significantly stronger in a warmer climate," said Tom Knutson, a climate modeler for the Geophysical Fluid Dynamics Lab, and the lead author of the study that used one the world's most powerful computers to simulate 1,300 virtual storms.

Hurricanes get their strength from warm ocean water, so higher water temperatures mean more energy for the storms.

"As a storm is moving across the ocean, it's evaporating water from the ocean's surface, and that's supplying fuel for the storm," Knutson said.

Knutson's study found that within 80 years, the average hurricane strength will increase by half a category in the five-step scale of destructive power.

"It could be the difference between, say, a roof staying on a house and the roof being ripped off," said Robert Tuleya of the Center for Oceanography at Old Dominion University.

Average wind speed could jump 15 miles an hour, rainfall two inches and storm surges several feet.

"In our simulations, you end up with some of these really monster storms," Knutson said.

The study says nothing about how global warming might affect the frequency of hurricanes. The researchers say that is next on their agenda.

ABC News' John Berman originally reported this story for "World News Tonight."