Global Warming and Katrina
From Light on Dark Water:

[R]egarding the question of global warming and its role in this year's epidemic of hurricanes: this chart from NOAA seems to put that question pretty well to rest for the time being, at least as far as this country is concerned. There is no correlation between whatever warming has occurred since the 1850s and either the number or severity of hurricanes striking the U.S. The possibility remains, of course, that the U.S. is not representative of the entire planet.

[link via Caelum et Terra]