It looks like Hurricane Katrina may not quite deliver the worst-case scenario blow to New Orleans.

That's cold comfort, to be sure.

Granted, I've never been particularly enamored with the hot, sticky climate of the Gulf coast, but right now I'm particularly grateful to be in Minnesota where our summers are (reasonably) comfortable, and the worst weather we have to deal with is the occasional tornado or blizzard.

Also, one might reasonably ask whether Katrina is as strong as she is because of global warming. That's an excellent question, and one I'm sure the experts will be arguing about before the cleanup has even started. But it is fair to assume the answer is Yes, given that hurricanes feed on warm water, and the water in the Gulf of Mexico is unusually warm (over 90F in places) this summer.

In more general terms, global warming leading to more severe weather doesn't surprise me a bit. The logic, for anyone with a background in physics or engineering, is straightforward: the Earth's atmosphere is basically a giant natural heat engine, driven between the temperature difference between the equator and the poles. When you raise the operating temperature of a heat engine, all else being equal, it speeds up and outputs more energy. In meteorological terms, that translates into bigger storms, higher winds, etc.

Of course, the "all else being equal" part is a bit of a kicker, since other things can come into play. For example, bigger storms (area-wise) mean more of the Earth's surface covered by clouds, which means a higher albedo, which means more sunlight reflected into space and less heat reaching the surface.