WASHINGTON - Global warming isn't to blame for the jump in hurricanes in the Atlantic, according to a prominent federal scientist whose position has shifted on the subject.

Not only that, warmer temperatures will actually reduce the number of hurricanes in the Atlantic and those making landfall, research meteorologist Tom Knutson reported in a study released yesterday.

In the past, Knutson has raised concerns about the effects of climate change on storms. His new paper has the potential to heat up a simmering debate among meteorologists about the effects of global warming in the Atlantic.

Many climate-change experts have tied the rise of hurricanes in recent years to global warming and hotter waters that fuel them.

Another group of experts, those who study hurricanes and who are more often skeptical about global warming, say there is no link. They attribute the recent increase to a natural multi-decade cycle.

What makes this study different is that it is by Knutson, a meteorologist with the National Oceanic and Atmospheric Administration's fluid dynamics lab in Princeton who previously has warned about the harmful effects of climate change.

He has even complained in the past about being censored by the Bush administration.

He said his new study, based on a computer model, argues "against the notion that we've already seen a really dramatic increase in Atlantic hurricane activity resulting from greenhouse warming."

The study, published online in the journal Nature Geoscience, predicts that by the end of the century the number of hurricanes in the Atlantic will fall by 18 percent.

It says the number of hurricanes making landfall in the United States and its neighbors - anywhere west of Puerto Rico - will drop by 30 percent because of wind factors.

It's not all good news from Knutson's study, however. His computer model also forecasts that hurricanes and tropical storms will be wetter and fiercer.

Kevin Trenberth, climate analysis chief at the National Center for Atmospheric Research in Boulder, Colo., said Knutson's computer model "fails to replicate storms with any kind of fidelity."

But NOAA hurricane meteorologist Chris Landsea, who wasn't part of this study, praised Knutson's work. "I think global warming is a big concern, but when it comes to hurricanes the evidence for changes is pretty darn tiny," Landsea said.

Hurricane season starts June 1 in the Atlantic.