The business case for the Paris agreement has nothing to do with climate change. It goes like this: It is better to be part of any confab than outside of it. Like saluting the flag or bowing your head in church, there is no cost to being insincere, but there is a cost to not going along.

Let us understand something: 195 countries will not be dragged kicking and screaming to sign any agreement that imposes a cost on them. Such deals exist only because they provide an international imprimatur to what politicians were going...