NIGERIA, Nov. 28 -- If the camel is a committee's version of a horse, then the concluding notes of the 30th United Nations Conference of the Parties (COP30) at Belem, Brazil were bound to be ungainly, weak, and messy. That is what you get from an emitting gathering of over 56,000 mostly subsidised attendees keen to etch their way into posterity. Leave aside the fact that some of the conference mongers might have been well-meaning, the final agreement was always going to be significant for what it omitted. It was also prominent for lacking any official role from the United States, a country where Make America Great Again has all but parted ways with notions of climate change.

For three decades, these events have drawn attention to climate...