Walshy, look up the word 'overwhelming' in a dictionary.
In any case, Freeman Dyson has made it perfectly clear that he doesn't consider himself in any way an expert in the field of climatology - he is a theoretical physicist and mathematician. And he does not deny that anthropogenic climate change is happening, anyway - he disputes that its effects are likely to be as harmful as predictions suggest:
http://e360.yale.edu/content/feature.msp?id=2151