Recent research may shed new light on whether the increase in hurricane activity on the Gulf Coast is part of a cycle that could end in a couple of decades, or a long-term climate trend that could last for centuries.

Two studies published this summer contend that the number of hurricanes counted in the early 20th century is lower than the number that actually formed. The reason: Weather-recording technology has improved to the point that scientists can see tropical storms now that they never would have known about 100 years ago.

The findings are important because in recent years, several researchers have factored in historical data to show that hurricane seasons have become more active. They have theorized that the more active seasons are linked to global warming.

But those theories could come into question if there were more hurricanes in the past than previously believed.

“If what I’ve done is reasonable, then taking into account what was missed, there’s nothing you can relate to global warming,” said Chris Landsea, a National Hurricane Center researcher who published one of the papers.

In the long run—the very long run—that would be good news for Mobile and other coastal cities, which enter every summer worrying about the death, destruction and rising insurance premiums that hurricanes can bring.

Insurance industry officials have said that they would be forced to raise rates and drop customers along the coast if global warming proves to create more risk for hurricane damage.

Landsea said he believes that global warming causes fewer hurricanes because it increases vertical wind shear, which tears apart the storms. The cyclones that do form see a slight increase in intensity, he said, but the difference is so small that humans couldn’t measure it.

The two studies, one by Landsea and one by Stony Brook University professors Edmund Chang and Yuanjian Guo, differ on how many storms were missed in the early part of the century.

Landsea believes that there were an average of 2.2 cyclones missed each year from 1900 to 1965, and that those missed cyclones totally eliminate any notion of a recent upward trend in storms.
FULL STORY at http://www.al.com/news/mobileregister/index.ssf?/base/news/1189330481234080.xml&coll=3