Those who follow the politics of the climate debate will be expecting Hurricane Katrina to be used to confirm catastrophic climate warming.

James K. Glassman says [Canada’s National Post, September 02, 2005 ] that one of the first out of the traps was, "Sir David King, the British government's Chief Scientific Advisor [who] warned that global warming may be responsible for the devastation reaped by Hurricane Katrina." The New York Times, says: "Because hurricanes form over warm ocean water it is easy to assume that the recent rise in their number and ferocity [sic] is because of global warming."

But scientists say the severity of hurricane seasons changes with cycles of temperatures of several decades in the Atlantic Ocean.” The recent onslaught "is very much natural," said William M. Gray, Professor of atmospheric science at Colorado State University.

What about frequency, though? The web site of the National Hurricane Center tells us that:

Giant hurricanes are rare - and they are not increasing. To the contrary. The peak for major hurricanes (categories 3, 4, 5) came in the decades of the 1930s, 1940s and 1950s, when such storms averaged nine per year. In the 1960s, there were six such storms; in the 1970s, four; in the 1980s, five; in the 1990s, five; and in 2001-04, there were three. Category 4 and 5 storms were also more prevalent in the past than they are now. As for Category 5 storms, there have been only three since the 1850s: in the decades of the 1930s, 1960s and 1990s.

The science of sea temperature and level is still evolving, and scientists have long pointed to a disparity that showed the atmosphere's lowest layer, the troposphere, had not warmed as much as the surface - contrary to greenhouse theory and model results. Dr Roy Spencer (U of Alabama) tells us:

This discrepancy between the UAH satellite LT trends and the surface thermometer trends has caused some consternation, since atmospheric physics suggests that sustained warming at the surface should be amplified with height in the troposphere, not reduced.

Hurricane Katrina has been a terrible tragedy, and may teach us to be better prepared for what nature throws our way. But to suggest it is man-made looks only like an attempt by interested parties to use it to their advantage.