Hurricanes and Climate Change

Chris Mooney has sparked a bit of discussion about the media's coverage of hurricane Frances, and whether reporters ought to be pointing out to the public the linkage between hurricanes and greenhouse-induced climate change. Mooney, using Ross Gelbspan's words as something of a surrogate, seems to be suggesting that reporters, if they are being honest with the science, ought to be sketching out the connection. Implicit in this is the assumption, common currency in the initial post and the comments that follow, that there's a global warming->more and stronger hurricanes link.

Well, maybe. But maybe not. And I think this is an important point that should be handled with some care, lest Mooney, Gelbspan and their ilk leave themselves open to the same sort of accusations of manipulation of the science that they so frequently accuse the climate change contrarians of committing.

Let's look first at Gelbspan's words, as quoted by Mooney:

Given the dramatic increase in extreme weather events, one might think that journalists, in covering these stories, would include the line: "Scientists associate this pattern of violent weather with global warming." They don't.

It would be lovely if Gelbspan cited a source for this claim that there has been a "dramatic increase in extreme weather events." I'm not sure he does. But let's check out the Intergovernmental Panel on Climate Change's dreaded summary for policymakers. On this crucial question of hurricanes, which is the whole raison d'etre for Mooney's post, the IPCC concludes that there is no evidence for increased hurricane intensity over the last half of the twentieth century. They go on to say that it's "likely" (a modestly strong assertion in the IPCC's lingo) that hurricanes will get stronger in the future under greenhouse climate change. On the question of hurricane frequency (here you have to burrow back into the detailed text of the full report) the IPCC concludes that there is no evidence of an increase in hurricane frequency in the past (one wonders where Gelbspan's "dramatic increase in extreme weather events" fits here) and , "there is some evidence that regional frequencies of tropical cyclones may change." (emphasis added)

This is not exactly the strong and vibrant consensus of the scientific community that Mooney seems to want the news media to be sharing as Frances does the lock-and-load thing off the Florida coast.

Don't get me wrong here. There is an important consensus that an array of climatological extremes is a clear likely consequence of greenhouse climate change, especially in the area of droughts, heat waves and more intense precipitation events. And that's important. The most significant climate-linked human problems come from swings - weather that's wetter than you expect, or drier. But Mooney seems to be wanting the news media to be doing something over the next few days that seems at best weakly supported by the science.

Posted by John Fleck at September 02, 2004 08:51 PM