Heading for Another "Bumpy" Hurricane Season

Warmer Seas Creating Stronger Hurricanes, Study Confirms

By Ker Than
LiveScience Staff Writer
posted: 16 March 2006
02:00 pm ET

A rise in the world's sea surface temperatures was the primary contributor to the formation of stronger hurricanes since 1970, a new study reports.

While the question of what role, if any, humans have had in all this is still a matter of intense debate, most scientists agree that stronger storms are likely to be the norm in future hurricane seasons.

The study is detailed in the March 17 issue of the journal Science.

An alarming trend

In the 1970s, the average number of intense Category 4 and 5 hurricanes occurring globally was about 10 per year. Since 1990, that number has nearly doubled, averaging about 18 a year.

Category 4 hurricanes have sustained winds from 131 to 155 mph. Category 5 systems, such as Hurricane Katrina at its peak, feature winds of 156 mph or more. Wilma last year set a record as the most intense hurricane on record with winds of 175 mph.

While some scientists believe this trend is just part of natural ocean and atmospheric cycles, others argue that rising sea surface temperatures as a side effect of global warming is the primary culprit.

According to this scenario, warming temperatures heat up the surface of the oceans, increasing evaporation and putting more water vapor into the atmosphere. This in turn provides added fuel for storms as they travel over open oceans.

Other factors less important

The researchers used statistical models and techniques from a field of mathematics called information theory to determine factors contributing to hurricane strength from 1970 to 2004 in six of the world's ocean basins, including the North Atlantic, Pacific and Indian oceans.

They looked at four factors that are known to affect hurricane intensity:

• Humidity in the troposphere—the part of the atmosphere stretching from surface of the Earth to about 6 miles up
• Wind shear that can throttle storm formation
• Rising sea-surface temperatures
• Large-scale air circulation patterns known as "zonal stretching deformations"

Of these factors, only rising sea surface temperatures was found to influence hurricane intensity in a statistically significant way over a long-term basis. The other factors affected hurricane activity on short time scales only.

"We found no long-term trend in things like wind shear," said study team member Judith Curry of the Georgia Institute of Technology. "There's a lot of year to year variability but there's no global trend. In any given year, it's different for each ocean."

The continuing (and all too familiar) refrains of the "Environmentalist Boogie." Those who look at the data see a recurring pattern in climatological history, those who build their little computer models see "Man-made Global Warming." Talk about "not seeing the forest, for the trees"... That's a perfect description of the "Mankind is evil and destroying the Earth" faction in the environmentalist movement (note how even the word should be a warning, environ-MENTAL).

Let me repeat it for those of you who still don't get it. Our written history is about 4-5000 years at most, our recorded weather observation, considerably less. The Earth, by contrast is what, 5-7 billion (that's billion with a "B") years old. Folks, there are patterns of weather that have existed for tens of thousands of years, millions of years if you include the ice-ages. We are currently in an "inter-glacial" period that means that we have been in an ice-age in the (recent, geologically speaking) past and will, presumably, return to that state sometime in the future. In between ice-ages, the planet heats up, just as we are currently witnessing.

This is a natural process over which mankind has little if any control and on which has little if any effect. I'm sorry if this offends your ego, but that is just the way it is, and it is the utmost in hubris for any scientist to presume to know to any degree of certitude what is going to happen in the next several decades. Heck we can't even predict tomorrow's weather with any consistency.

Are we going to experience an unusual number of category four and five hurricanes again this year? Very likely so, but there is nothing-repeat nothing-that we can do about it, except prepare ourselves.

"Gray skies are gonna clear up..."

Full Story: Scientists Discover Heat Causes Hurricanes...DUH!

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