“if you’re willing to put aside the conspiracy theories for a moment we will move on”

The publication of the US National Oceanic and Atmospheric Administration’s State of the Climate in 2009 report, with analysis by the Met Office, prompts the Daily Telegraph‘s Tom Chivers to produce the most sensible piece I’ve seen for some time on the subject.

As Dan Gardner says in his wonderful book Risk: the science and politics of fear, to which I will be returning, the phrase “very likely” is about as strong as scientific language gets, and a 95 per cent confidence level is by common convention taken to mean established fact. Obviously, if you’re of the opinion that the IPCC is actually run by the Illuminati or something, then its findings will be of little interest to you, but if you’re willing to put aside the conspiracy theories for a moment we will move on.

So there are the two facts: the world is warming; mankind’s action is almost certainly causing that warming. What’s actually interesting, of course, is where we can go from there. Warming in and of itself is not necessarily a bad thing. We want to know how it will affect our lives. Here the evidence is more equivocal: the IPCC reckons it is “likely” (66 per cent chance) that it will lead to sea level rises and increased droughts, for instance. But the dire warnings of some activists are far from certain; the acknowledged imperfections of computer modelling, especially when it comes to feedback systems (both positive and negative), make it very hard to predict the extent of those two problems.

Read the whole thing.