I'm currently watching The Great Global Warming Swindle on the ABC. It all appears like they are just making guesses... probably in both directions. Such historical science involves so many estimates, so many guesses.
I saw it when I was working for CSIRO - my boss was a modeler, constantly analysing the historical data and feeding in parameters to try and predict crop yields so that a good model could be determined to help establish the relationship between those parameters and the outcome. From that practical steps could be performed. Published in a journal there will be a reference to me because I wrote some simulation software as work experience before I began there. I think it is good work.
BUT the software that my boss used (not the software I wrote) had hundreds, if not thousands, of parameters. You take such a complex system as our world and in particular weather systems and it is hard to make predictable models that really show what is the cause and the relationship between these parameters.
So does this mean we can sit back on our hands? No. I think like everything else it needs to be done with consideration and moderation though. There is always someone that is looking to capitalise from any opportunity, and many already are (for better or for ill). Living greener is always a benefit, however I do see the one point that was made about the developing nations being disadvantaged. Certainly there is a need here that needs to be addressed. They hold one advantage however - they can make the jump of the last 30 years of development, where we have learnt the hard way, and use the modern technologies. The cost is still prohibitive, but if it is determined that this is the way forward then subsidising the alternative power sources is a requirement.
It is interesting that the discussion of alternative energy sources has almost died out. Have we forgotten that we are using non-renewable energy now? That in itself is good reason to develop and promote the development of alternative, renewable energy sources.
I think it was an interesting show, and interesting discussion (if it could be called discussion, there was very little listening going on, and a hell of a lot of stating opinion) . It seems like there is a lot of misleading "evidence" on both sides of the fence (I remember reading some comments on Gore's doco - which I should watch at some point). I certainly site to the left side of the argument still, but as one of the commentators said, it is our position to remain skeptical.