A while back I read a letter (to a car magazine, BTW) where someone was using the 'there's no hotspot' argument against AGW. What interested me was that they went on to say how they had realised that 'of course' this was the case, as 'obviously' global warming required a layer of warm air to raise the surface temperature.

The point here is that they were using a fairly standard argument, but had added their own logic to it, based on how they assumed global warming worked. This then seemed clearly true, as it was (as far as they knew) internally consistent and, most importantly, gave them the 'right' answer.

I think there is a fair amount of this in the AGW debate. I've seen it called motivated reasoning, which is just a fancy term for when you start with the conclusion and work towards that. This is based on what feels right to the individual, and the act of coming up with an explanation which sounds correct reinforces the conclusion. I saw a reference an academic paper about some of this posted on another blog, but unfortunately I've lost the link. Basically the research found that if people were presented with some facts then encouraged to come up with an explanation for them, they were more likely to continue to believe these facts were true even if presented with contradictory evidence.

I should also say this does happen on both sides of the debate. The concept of AGW feels right to some people and wrong to others, and some of the pro AGW arguments on blogs and the like mangle the science just as badly as the anti AGW arguments. And this is a problem because when 'sceptics' are able to find problems with arguments pur forward for AGW, this reinforces their beliefs that it is all nonsense.

Thanks.