Given lack of time to research the subject, I personally assume global warming is an actual real problem ... but such a belief ought not be a pre-condition for reducing emissions (and supporting reducing pollution in general.)
As far as matching models Taleb would no doubt point out that most economists' models showed that the chance of the financial crash we just experienced was nil. Saying the models have similar results in insufficient to argue they are correct. Taleb's position is not that global warming does or doesn't exist, just that over-reliance on incomplete models is problematic. What if in 10 years all the models are revised based on new theories or data and scientists conclude global warming isn't happening? Spewing out measurable amounts of CO2 is *still* a bad idea.