The AP is reporting on research to be published Friday stating that the intensity of worldwide hurricanes has increased significantly over the past decade. Scientists at Georgia Institute of Technology say that the number of powerful hurricanes (cat 4 and 5) "rose to an average of 18 per year worldwide since 1990, up from 11 in the 1970s." The report will be published in tomorrow's Science magazine.
Some scientists over at the NOAA question the data saying that measurements taken in the 1970s were not accurate due to a technological difference between today's instruments and those that were used over 25 years ago. Personally, I don't think I need a anemometer to tell me that storm intensity is on the up and up; just look at how fast New Orleans washed out to sea. I've never heard of such destruction from a hurricane, and to think that the 6 of the 10 costliest (in $ not lives lost) hurricanes have occurred in the past 10 years definitely drives the point home: its only getting more intense and if you're living along the Gulf Coast, it might time to trade in your swimsuits for snowsuits and see what Michigan has to offer.
However, if you compare the top 10 strongest hurricanes on record between 1900 and 2004, only 2 (including Katrina) manage to make the list. It seems the most destructive hurricanes in U.S. history aren't necessarily the most intense but are causing the most damage, which begs the question: are we just lucky? What happens when more cat 5 hurricanes acutally stomp all over Miami, Tampa Bay, Orlando, the summer cottages of Hilton Head or Gavelston, TX? The financial damage at that point will be incomprehensible.
So, maybe the data of the past 75 years is not worth considering, since, as Chris Landsea of NOAA says, there just aren't sound results coming from anything pre-1985, due to inaccurate wind measurements and old-school equipment. But that puts us back to focusing on what we do have good data for, the past 15 years. That data isn't any friendlier. Since 1990, the U.S. has dealt with 4 different category 4 and 5 storms. Thats alot of big storms in just a 15 year period. In fact, outside of hurricanes Andrew and Hugo ('92 and '89) the last category 4 or 5 storm was in 1969.
Is the answer in building stronger, more expensive levees? Rebuilding the natural barrier islands that oil and gas companies have decimated could be a great addition to NO hurricane strategy. Checkout the CS Monitor's article on where this rebuilding should start.