I don't think the problem is necessarily the population numbers. I don't wanna be that person, but I am 100% that person, and I think balls to the wall capitalism is the real culprit here. governments and big corporations refuse to divest from unsustainable manufacturing resources and practices. if we were able to curb that (and I don't know how we'd be able to) then I think it'd result in measurable change much more effectively than expecting people to 1) have less sex or 2) have sex using effective birth control methods. you don't get the latter without REALLY good sex education and accessible healthcare and that doesn't sound like a package deal with the one-child policy