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"The key is to recognize what is happening and what will be happening in the future," said Kevin Trenberth, head of the climate analysis section at the National Center for Atmospheric Research in Boulder, Colo. "That helps us prepare."
The theory that increased ocean and atmospheric temperatures could increase the intensity of hurricanes has been around for years. It works like this: Greenhouse gases such as carbon dioxide and methane trap heat in the atmosphere and warm the ocean. Warmer water produces more water vapor, which is the fuel that drives hurricanes. More fuel means increased intensity.
In 1987, a study from the Massachusetts Institute of Technology concluded that a doubling of carbon dioxide in the atmosphere would yield "a 40-50 percent increase in the destructive potential of hurricanes." Another breakthrough came last year in a study written by scientists Thomas Knutson and Robert Tuleya. Using supercomputers, they ran models of simulated hurricanes. Nearly all the models revealed that increased greenhouse gases would create stronger hurricanes on average. he trapped gases would push future hurricanes an average of a half-step up the five-step intensity scale over the next 75 years, the study showed. Knutson cautioned that the exact amount of buildup in greenhouse gases is tough to predict.
"But I think you can use what we found to get a rough indicator of how much more intense the storms will be in the next few decades," said Knutson, who works at the government's Geophysical Fluid Dynamics Laboratory in Princeton, N.J.
Current research shows that the waters in the Atlantic basin are as warm as they've been since scientists began recording temperatures more than 100 years ago. The average for the last decade was one-tenth of a degree centigrade higher than the previous high, recorded in the late 1940s and early 1950s. The increase doesn't sound like much. But researchers such as Trenberth have concluded that it is not a normal fluctuation in ocean temperatures, or the effect of El Nino, a current of warm ocean water. It's an increase in greenhouse gases such as carbon dioxide, they say."
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http://www.sptimes.com/2005/05/02/Tampabay/Warmer_Atlantic_basin.shtml