Honestly? We don’t even have to try. It’s a tragedy of the commons thing: life forms will reproduce and spread until they die off. Smear some bacteria in a Petri dish and the same thing happens. A lot of it has to do with reproductive healthcare (the lack thereof) in developing nations. Basically, people keep having unprotected sex. Biological reproduction is so fundamental that even if every nation in the world had a stable government, I’m not sure there’s anything we could do that isn’t super dictatorship-y. And even then..

It’s pessimistic, yeah, but we don’t have to even try to have babies. People will keep making that individual choice until we run out of food or energy or something and lots of people, most likely the poor, die.