Every business asks a similar question every day.
"If I decide to do A, I might make $B dollars or lose $C dollars. Is this a wise thing to do?"
We tend to think that Pascal's cost benefit analysis was flawed. That doesn't mean we should drop the principle altogether!
I'm all in favor of the rational cost benefit analysis you hint at. Most environmentalists are not - witness the reaction to Bjorn Lomborg.
But anyway, that misses the point. The wager isn't cost-benefit analysis where probabilities and expected values are certain; it's decision making in the absence of compelling evidence. What you have essentially done is respond to the multiple claimants problem by saying, "But any form of belief in the Christian God pulls in more or less the same direction." In the uncertainty that the wager confronts, however, "reducing CO2 emissions" and "increasing CO2 emissions" have the same expected value - that is, they are equal claimants. Hence my point that the multiple claimants problem is equally devastating when the wager is applied to global warming.
I totally beat you to the punch on this one :D
If the bible is wrong but the accepted answer, you lose a finite amount of hedonic pleasure in the near term and there are some short term benefits (smaller amount of killing/stealing/coveting).
If the bible is right, but not accepted, you will burn in hell for all eternity.