The Economist has a special survey on climate change (you get to read the intro for free. The rest is sub-only :-(). Its headlined “The heat is on” and storylined “Global warming, it now seems, is for real.”.
[Oh wonderful. I read the special supplement on the assumption that it has most of the content, and then I get to the leader column which is far more interesting. I need to add an addendum to this post...]
Their conclusion is:
This survey will argue that although the science remains uncertain, the chances of serious consequences are high enough to make it worth spending the (not exorbitant) sums needed to try to mitigate climate change. It will suggest that, even though America, the world’s biggest CO2 emitter, turned its back on the Kyoto protocol on global warming, the chances are that it will eventually take steps to control its emissions. And if America does, there is a reasonable prospect that the other big producers of CO2 will do the same.
So… whats changed? Not all that much. Katrina, of course (yes I know; but its attitudes we’re talking about; and anyway they cite the Emanuel and Curry papers). Perhaps the emerging carbon trading (which of course the Economist rather likes) and the chance to do cost-benefit analyses that show the costs are not as high as some people claim (there is even a bit about costing in worst-case scenarios, just for mt). They cite the Bryden paper (and get a pile of stuff about the Gulf Stream wrong; you’re better off with Real Climate of course). Otherwise its not obvious why they’ve changed. Too embarassed to be in Bushs company any longer?
[Addendum: OK, reading the leader column makes their thinking clearer: they put up the TAR 1.4.-5.8 range; anything higher would be catastrophic for sea level; there is uncertainty; should we spend to avert uncertain distant risk?; yes, it looks big enough; costs may be 1% or less; real problem is political. But they could have said most of this years ago]