Well, one answer might be for the planet to get rid of a large portion of those unwanted guests.
Robert (“Don’t call me Thomas”) Malthus (1766–1834) was a minister in the Church of England who had a flair for scholarship in the nascent fields of demography and political economy.
In , Malthus asserted that there were two types of “checks” on population growth: “Preventive” and “Positive.” The Preventive Check would come into play when a population crisis was created by overconsumption of food resources.
Because humans are uniquely capable of responding rationally to such a crisis, their best move would be to forgo childbearing until the balance between population and available food resources was restored.
I am mindful of Mark Twain’s famous displeasure with statistics (“Lies, damn lies, and statistics!
”), and I know that thoughtful people on opposite sides of an argument often marshal competing data to prop up their views.
I will readily concede that he got some things badly wrong, notably his theory that human population would double with each generation.
But, while he may have wildly miscalculated the rate of population growth (and also the increase in available food), he might also have gotten some other things chillingly right. In it, he argued that increases in food production were beneficial to a nation’s people, but that those increases also stimulated population growth.
This is what is termed the “Malthusian Catastrophe.” As long as the balance between food production and population was maintained, things would be fine.
But what would happen when they fell too far out of balance?