The problem is Pascal's Wager was comparing immeasurable things. Since it's 100% certain that you'll die and 0% certain that god exists (as there is no possible method to measure it), Pascal's assertions were completely invalid, in so far as it is applied to the improbable. Unlike the existence of god, we know 100% that a planet's climate can change from the atmospheric composition as well as other criteria, we also know 100% that man is capable of outputting the very chemicals that can cause climate change.  So for Pascal's Wager, to be correctly applied to this situation, it would be an issue of determining the probability of the damage (not the existence of because that's not a loss scenario in and of itself) of man made climate change vs the cost of preventing it (gain scenario). Neither of those are immeasurable values, humanity has extensive understanding of risk estimating which we frequently code into law (because vehicles and structures need a margin of safety build into design); and one could quite readily sit down and write an entire treatise on the risk estimating of climate change. Ultimately, the issue becomes less and less of an individual concern and one of a species concern, as the problem is not simply limited to man-made climate change, but natural climate change as well.