In the celebrated thesis of Thomas Malthus (https://en.wikipedia.org/wiki/An_Essay_on_the_Principle_of_Population) vice and misery impose the ultimate natural limit on the growth of populations.
This scientist, JOHN B.CALHOUN, PH. D., National Institute of Mental Health wrote " Population Density and Social Pathology" in the 1962 edition of Scientific American....and it changed my life's direction.
The solution is simply family planning
China tried to enforce this on their populace....it worked for a while- but not without grave suffering.
Today China has a lower percentage living in extreme poverty than the US...So it worked for them....but again...we've all heard of the forced abortions. The embryos in the streets. The imbalance of abortions (far more girls than boys) has resulted in a very dominant (54%) male population in China.
The big question is....how do we persuade our humanity to control its' own growth in a pleasant way.?