Preface: I believe in global warming.

Now that that's out of the way, this argument is designed much like Leibniz's argument for the existence of God.

Since we can't know either way if God exists, we essentially have 4 outcomes. You believe and he doesn't exist, you believe and he does, you don't believe and he does exist, and you don't believe and he does not exist. Sparing you the breakdown of each, the argument boils down to you might as well believe in God because you essentially have nothing to lose if you do believe and are wrong and everything to lose if you don't believe and are wrong.

This argument has the same issue. You don't really have nothing to lose. Sure there's obvious benefits to going green, but they certainly come at great cost and effort. So for those who don't believe in global warming, especially those who own/operate/are stakeholders in profitable business known for harming the planet, they have a lot to lose by going green. Therefore it's oversimplified by saying we only gain by being greener.

Again, I don't actually support destroying the planet, nor am I a climate change denier. Merely pointing out the gap in logic used in this argument.