The supposed rationality of this argument has been demolished in previous threads on this site, eg by Mike Marrotta. It uses a common but misleading decision choice of two alternative actions, what is known as a false dichotomy. In reality there are many or an infinite number of problems and choices and the same for the number of possible responses.
For example, what should 'we' do about global cooling, perhaps you were around when that was the scare-du-jour, it was dropped as warming proved more effective in securing government money and green support.
A quick way to see how silly it is, is by saying, whatever and all unpleasant effects can be imagined, we should insure against, whatever the risk. The insurance premia soon reach $infinity. The rational approach is to evaluate evidence, probabilities, costs and benefits.
For the case of anthropomorphic global climate change that is easy. The case is based on 'false altruism'. that is partisan concocted evidence pretending to be in the human interest but actually in the interest of small groups. If anything the earth is now entering a cooling period.

About 10 years ago Danish economist Bjorn Lundgren did some careful work on the economic costs of dealing with global warming compared with the consequences and concluded that it would be cheaper to deal with rather than prevent. He wrongly accepted the so-called evidence and explanation but that was not good enough, only putting whole national economies on a path to the stone age is sufficient and he was hounded down by the believers.

I seldom mark down, I do so here as the thread is unhelpful, and in short -spam.

"One fool can ask more questions than ten of the wise can answer."

Climate change is not a costly problem driven by human activities until there is evidence to prove that human activities can actually change the outcome. The promoters can't even give a reasonable scientific estimate of the outcome, much less prove humans can change it.