Putting it Plainly...

While I agree with what the man is trying to say, I think is logic is flawed. He's posing an ecological version of "Pascal's Wager." His thinking assumes that the two choices are both equally logical. Since it is a 50/50 choice, we should choose the option with higher benefits and less risks. But the debate is over the hard science, and people who don't believe in GCC are convinced of the evidence for their perspective.

I'm with Mark. Replace "global climate change" in the rows in his table with "invasion by aliens" or "terrorist attack" or "flu pandemic" or any other possible threat and I think the problem of his argument becomes obvious. It can be used by anyone with any agenda to push any radical course of action. The reason we need to do something is that climate change is probable, not that it's possible.