True. But the "majority" is not as big as you think.
> there will be 1 billion less wealthy people
Just wrong. There are lots of ways to reduce emissions without any effect in wealth. Eating less meat is one example.
> for no particular net gain.
Very wrong, there are huge gains: https://www.theguardian.com/environment/2020/sep/21/worlds-r...
> I advocate the radical approach of encouraging people to have less children.
I knew you would say this, I was just waiting for it. Global birth rates have been in freefall for decades now, it's tragic that people don't know about it. You'd assume that supposedly "better" education in western countries would make people more aware, but western governments are only concerned with maintaining global western hegemony which requires falsely accusing the rest of the world and keeping their citizens ignorant. Also, you can't force people to have less children, that's inhumane. I suggest you go through the following links.
https://www.youtube.com/watch?v=QsBT5EQt348
https://www.youtube.com/watch?v=FACK2knC08E
https://www.youtube.com/watch?v=hVimVzgtD6w