As reported and commented upon by the lamestream media and most "leaders," pundits, left-wingers, and Hollyweirdos, it is pure junk science, and as has been noted by commentators on the issue like Michael Crichton, many academics in the field who promulgate the "sky is falling" line are purely agenda driven, whether financially, ideologically, by peer pressure, or otherwise.
Everything in science that is reported by the media is simplified and wrong. As for Hollywood - how can you cite Micheal Crichton? Not just junk science but junk literature as well...
But again, just because the press report it badly (be it cancer scares or anti GM crop scares or anything else) does not mean that the scientists are liberal agenda driven - or even peer driven or ideologically driven or financially driven. Where is the money for the Royal Academy in making these claims? how do they benefit? (answer - the don't - they may suffer because they bring bad news to politicians and business and the man on the street who do not want to know)
Even if the US had signed up to Kyoto (which in many ways was a bad agreement all round, not just for the US) by now it would probably not have made any dfference to Katrina. But it may make a difference in the next ten or twenty years, and the longer it is left the worse the effects and the longer they will be.
People who pull the junk science line and ignore the whole scientific community around the world (except for a few in America who rely on Federal funds, and don't want to annoy the oil industry) are like the people who ignored the scientists who said there is a big storm coming and they ought to move out of New Orleans. Bad news is not always Liberal scare mongering.
The sad thing is that in the UK, and I am sure many other places, many people are saying that Katrina WAS caused by global warming, or at least that is was made stronger by GW, or that even if it wasn't the next one will be, and it serves America right for not signing up to Kyoto - true or not there is little sympathy, since America is seen by the rest of the world as a dirty neighbour. And it is not just the left wingers saying that.