Local environments have carrying capacities; see eg. the Rwandan genocide for a reasonable convincing example of what happens when they are exceeded. However,

Local environments have carrying capacities; see eg. the Rwandan genocide for a reasonable convincing example of what happens when they are exceeded. However, I don't think we are anywhere near the carrying capacity of the planet as a whole, particularly since vast slabs of it are actively depopulating (Russia, Japan, rural areas of most industrialized countries, etc).