Increased severity of hurricanes

There's a brief article in the current Economist, talking about the increased severity of hurricanes in recent years:

Looking at the hurricanes themselves, though, they found no long-term trends in the number of storms per ocean basin or the length a storm lasts, except in the North Atlantic, where both increased. That is unfortunate news for Caribbean countries and the United States, which bear the brunt of those storms. But it suggests that whatever is increasing hurricane incidence it is not — or, at least not solely — to do with ocean warming. If it were, such increases would have shown up in other places where the sea is getting warmer.

Nor was there any increase in the maximum windspeed that storms attained anywhere. What there was, however, was a doubling around the world of the proportion of storms in the most destructive categories (4 and 5 on the Saffir-Simpson scale usually employed by meteorologists). And, although the exact rise in that proportion varied from basin to basin, all of them saw a significant increase.

This is the sort of troubling result of too little data: the studies could only cover the last 35 years, as the satellite coverage was too spotty before 1970 to provide valid data. It may indicate a significant result of higher ocean surface temperatures interacting with weather patterns, or it may be part of a longer-term shift in weather patterns. We can speculate, but the data does not prove one thing or another.

That aside, expect more banging of the drum for the Kyoto-worshippers, as this report gives them some more numbers to use for their own purposes.