No vision here, but it looks like developed countries are already working on it by themselves, with the demographic change we're able to observe. If that were the way, strong borders would need to be built.

What about the not developed countries? That's where most of the population growth is happening.

Should the developed world do frequent culls of the less fortunate in addition to the strong borders?

IDK. Maybe let them develop until they also reach the state of lack of desire to procreate.

That's what China has been doing. It's greatly increased its emissions.

Maybe what trump is doing is it