Authors argue that if the west can receive 4 million Ukrainians, or perhaps eventually 10 million, it can accept climate refugees without limit, even if they number in the hundreds of millions, or eventually billions.

That claim is absurd. For any kind of burden, there is a limit.

It is clearly true that western countries are motivated by prejudice when they decide how to treat various groups of refugees. But western countries would find it hard to admit hundreds of millions of refugees even if they were all Europeans, even today. 20 years from now, when all these countries will have shortages of food and millions will be homeless, it would be even harder.

The only way for the world to get through this is to cut our greenhouse emissions, fast.