Leo Hickman points us to this interview with Richard Muller, in which it is suggested that the BEST team have been looking at the attribution aspect of AGW, and will be publishing their results shortly.
CM: Do you agree with the UN’s climate panel that the majority of the warming going on is being caused by human activity, burning fossil fuels?
RM: We haven’t yet finished our work on the human component of this. It looks to me like we will be in agreement with that [Muller says he'll be publishing his conclusions in the next few weeks].
But I do agree that the global warming has gone up. That, I think, is the main, if you want to call it a change, it’s the main result that I will now stand behind as a scientist, using my scientific credentials, doing the work that we did very carefully, that six months ago or a year ago, I would not have been wanting to stand behind. It does agree with the previous groups. We have achieved a better precision than the other groups have achieved, but it is a real effect.