Biologists use the term "carrying capacity" to determine the maximum population size an environment can support, and it's a fairly well understood concept there. Of course, with humans it's very different from animals, because there are more complex variables involved in sustaining civilization and we are sentient creatures with the ability to control and forsee future problems. I will say that earlier predictions of human overpopulation have often completely failed to account for technological changes in agriculture, including both Malthus in the 19th century and the Ehrlichs in the 20th century.
The best way to rid humanity of the issue of overpopulation involves urbanization, education and the industrialization of agriculture. Poor and rural countries have large birthrates: children do a lot of work in smallholdings and family farms, and poor countries with lousy sanitation and healthcare (as well as low female education) will see many huge family sizes to compensate for deaths. This is not, as some people imply, a racial or cultural thing: we see the exact same family sizes as you see in Nigeria and Uganda today in peasant families in France and Spain many years ago.
I disagree.
If humans were really intelligent, they'd go back to agricultural lifestyle as it was back a couple thousands of years ago - but with the difference of using advanced technology only as a last resort (in cases of significant medical needs). But to not use it otherwise and focus on art, sport, mental training and craftsmanship instead.
The picture I have in mind here is the village in Star Trek: Insurrection, where Picard and his crew visit and first think the people there are "in need of help" because they are living agricultural and modest, only to find out that they have all the technology incl. the Warp drive available - but are not using it - because it would distract them from their modest lifestyle.
A very underrated movie indeed. Tells you a lot about today.
With all due respect, I think you are overly romanticizing agricultural societies. There's nothing wrong with wanting to live in the countryside or living off the fat of the land or maintaining simple pleasures. I could totally understand why people dislike urban life and prefer solitude. However, humanity's tendency to destroy nature with utmost efficiency did not begin with industrialization. Indeed, as far back as the initial spread of
Homo sapiens as hunter gatherers, we saw the widespread elimination of apex predators. Primitive farmers pioneered the slash and burn technique of cultivation. a process which eliminated almost all of the old growth forests of Europe before the birth of Christ. Indeed, when you see slash and burn today in the Amazon or Sumatra, it tends to come from small farmers and ranchers. Likewise, there is a reason population growth is so massive in farming societies: it's because education is limited because all children are expected to help out rather than get educated.
