I have spent the morning patiently generating data from a Wikipedia article on hurricanes
and turning it into this fine picture (you have to click on it to see the latest years):
As you can see, the trend is up and down since 1950, more up than down in latter years, consistent with climate change theory. Then I find Kerry Emanuel's Graphics Pertaining to Tropical Cyclone Trends and Variability which, if you click here show a very close relationship between sea temperature and hurricane/cyclone intensity, as expected.
So at very least, the perception of increased hurricanes is consistent with global warming. All the more reason to adopt the hurricane nomenclature suggested y Greenpeace a few years ago: Hurricane Esso, Hurricane Texaco &c.
I have combined, in an amateur way,using MSPaint, two graphs, one of hurricane intensity, and one of global temperature. It shows a fair fit between the two. By the way, the red line is from a sceptic, showing a downward trend in latter years (as opposed to the upward trend over the longer period), except that hurricane intensity increases away from temperature after the Pinatubo volcano. Maybe there is a hurricane stimulating effect from the dust injected from the volcano. I make no claims for this, only an interesting observation. More research needed, to coin a phrase.
The jury is still out on this topic as far as I know, but the prima facie evidence it that there is a relationship between hurricanes and global temperature.
[Update 1.9.13: Goldenberg et al find that hurricanes increased significantly between 1995 and 2000 in the North Atlantic.
Flemlose on Skeptical Science shows a clear trend of increasing major hurricanes and decrease in hurricanes and tropical storms worldwide 1970-2012
Here are his results:
end of update]
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