Scientists say warming threatening Fla.

TALLAHASSEE, Fla. - Florida's governor cautiously entered the debate Wednesday over whether rising global temperatures are to blame for an increase in the number of strong hurricanes, meeting with two researchers who say global warming is threatening Florida with a long-term future of more bad storms.

Bush met with Peter Webster and Judith Curry of the Georgia Institute of Technology, who published research last year showing an increase in global hurricane intensity, with a doubling of the number of Category 4 or 5 hurricanes since 1970. That increase coincides with a rise of nearly 1 degree Fahrenheit in ocean surface temperatures, they say.

While they agree with other scientists that the Atlantic basin is in a natural cyclical increase in hurricanes, they argue that can't explain by itself such a dramatic increase in strong storms. Warmer temperatures globally mean warmer water, which is what fuels hurricanes.

"It's very complex, but there's one thing that we do know: if you increase these surface temperatures you're going to get more intense hurricanes," said Curry. "I think we can say — it's not totally conclusive, but with considerable confidence — that there is this connection between global warming and increased global hurricane intensity and the increased number of hurricanes in the north Atlantic."

There isn't scientific consensus that global temperature increases explain increased hurricane intensity, and there are some researchers who say there isn't a continuing long-term pattern of global warming at all.

The debate is something of a storm itself, and Bush joined it cautiously.

"He said they presented some pretty compelling information," said Bush spokesman Russell Schweiss, declining to say whether Bush agrees that global warming is increasing the number of strong hurricanes. "He encouraged them to continue with their research."

Hurricane Alley Heats Up

Water temperatures in areas where hurricanes form in the Atlantic Ocean have warmed up over the past century and human activity could be the reason, scientists report.

To develop into a hurricane, a tropical storm needs its primary fuel—water—to be at least 80 degrees Fahrenheit (26.5 Celsius).

Previous studies suggest that warmer temperatures can fuel stronger storms. Long-term trends show that global ocean surface temperatures have warmed up in the past century, and that this is helping to create stronger hurricanes.

A hurricane spawning region in the Atlantic Ocean off the coast of Africa has experienced more extreme temperature variation than other areas, according to new computer simulations that tease out the long-term change from other known variations that can last decades.

The water temperature in this "hurricane alley" has risen several tenths of a degree Celsius over the 20th century.

Global warming weakens vast Pacific climate system

WASHINGTON (Reuters) - Climate scientists identified a likely new victim of global warming on Wednesday: the vast looping system of air currents that fuels Pacific trade winds and climate from South America to Indonesia.

This could mean more El Nino-like weather patterns in the United States, more rain in the western Pacific and less nourishment for marine life along the Equator and off the South American coast.

Known as the Walker Circulation, this system of currents functions as a huge belt stretching across the tropical Pacific, with dry air moving eastward at high altitude from Asia to South America and moist air flowing westward along the ocean's surface, pushing the prevailing trade winds.

When the moist air gets to Asia, it triggers massive rains in Indonesia. Then it dries out, rises and starts the cycle again, heading east.

This important system has weakened by 3.5 percent over the last 140 years, and the culprit is probably human-induced global warming, scientists reported in the current edition of the journal Nature.