“I can’t get over these numbers: The 1980s saw three official Category 5 hurricanes. The 1990s saw two. The 2000s, so far, have seen eight…” says Chris Mooney.
But what are these numbers supposed to mean?
Well, Chris doesn’t say what they mean, but since he talks about paradigm shifts (!?!) I’m sure we’re supposed to be relating these numbers to global warming in some way. And his co-bloggers comments clarify that these numbers *are* supposed to be linked to GW.
But in what way? The world hasn’t suddenly got warmer since 2003 (indeed 1998 was warmer than 2003). And (as Chris says) there were 6 cat5 in the 60s, which was cooler still. Perhaps the relevant areas of sea have got warmer? Possible, but in that case I’m pretty sure people would have noticed and written it up (looking a bit harder, there is this, from RC (scroll down to fig 2) which shows a sharp increase recently in trop atl SSTs. But still doesn’t explain the large number of cat 5′s in the 60s).
If you want to know if its got warmer, then hurricanes are clearly a poor indicator – the record is too noisy. And we have a far better record: that of the temperature. If you want to know, conversely, if GW is going to lead to more or deeper or scarier hurricanes, then counting numbers by decade isn’t a good idea either.