GLOBAL WARMING DECREASES NUMBER OF CATEGORY 4 AND 5 STORMS

New Scientist reports:

A massive global increase in the number of strong hurricanes over the past 35 years is being blamed on global warming, by the most detailed study yet. The US scientists warn that Katrina-strength hurricanes could become the norm.

Worldwide since the 1970s, there has been a near-doubling in the number of Category 4 and 5 storms – the strength that saw Hurricane Katrina do such damage to the US Gulf coastline late in August 2005.

Peter Webster of the Georgia Institute of Technology, Atlanta, says the trend is global, has lasted over several decades and is connected to a steady worldwide increase in tropical sea temperatures. Because of all these factors, it is unlikely to be due to any known natural fluctuations in climate such as El Niño, the North Atlantic Oscillation or the Pacific Decadal Oscillation.

Okay, I'm no expert on hurricanes or statistics but I have looked at the number of hurricanes to have struck the United States and the strengths of these storms. This supposed massive increase in category 4 and 5 storms didn't seem quite right.

To check the figures, I went to the National Hurricane Center's list of the most intense hurricanes to strike the United States during the period 1851-2004. (Bear in mind that the study above is for global hurricanes and the figures I cite are only for storms that actually struck the United States.) I then broke the figures into the following year groups to parallel the study as closely as possible. The breakdown for category 4 and 5 storms by period is as follows:

1901-1935 – 7
1936-1970 – 6
1971-2005 – 4 (Includes Katrina, not on NHC list)

It looks to me like the incidence of category 4 and 5 storms is actually decreasing. Then again, maybe this is nothing more than flawed Beck Logic™ – see at

http://timlambert.org/2005/09/hypocrisy/

If so, here's Fact-Check Boy's chance to set me straight.