'Hidden Hurricanes' Upsetting Global Warming Theories?

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. Chang and Guo, who both work in the Institute for Terrestrial and Planetary Atmospheres at the New York-based university, believe the number of missed storms is lower, less than one a year after 1910, and that the upward trend still exists but to a lesser extent.

Before the advent of weather satellites in 1966, the only way to know whether a tropical cyclone had formed was to feel the winds whipping from the shore or the bow of a ship.

Landsea's theory is based on how frequently tropical storms hit land both before and after satellites came into use. Before 1966, 75 percent of known storms hit land. After satellites started noting mid-Atlantic storms, that dropped to 59 percent.

Landsea used statistical analysis to determine that the blind spot in the Atlantic Ocean caused scientists to miss about 2.2 more storms per year in the early part of the century.

Chang and Guo employed a different method to try to glean the same information. They used ship observations from the early part of the 20th century and recent hurricane tracks to find the probability that a storm would spin around in the Atlantic and never encounter a boat.

"Even in the early 20th century, there was a lot of trans-Atlantic traffic," Chang said. "If a storm came close to a shipping route, it's unlikely it would not be detected."

Chang said his data show an increase in hurricane activity in recent decades, but he was quick to say that the debate about what caused that increase is far from over.

Regardless, the Atlantic is in the midst of an energetic hurricane cycle that will probably last until 2020, experts agree. And even less active years can be destructive -- as was the case in 1979, when Hurricane Frederic battered Mobile.

"We'll still see an enhanced risk for hurricanes on the U.S. coast and in the Caribbean," Landsea said.

Look at it this way, from historical records the 1900 Galveston hurricane was known about when a beach goer shouted “thar she blows”. The time was so short they couldn’t get off the island before it was completely flooded. About 12,000 people may have died, no one really knows, Galveston was destroyed.

Same with the 1935 keys hurricane, that killed the WWI vets building the overland railroad. They knew about the hurricane hours before it hit. They still aren’t sure how strong it was, but have put some numbers down.

I wonder what the hurricane count was during the medieval warm period?

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.