Most people have heard the familiar phrase "the tragedy of the commons", referring to the destruction of a common resource (eg. a grazing pasture) by multiple independent, rational actors each acting in their own self-interest (eg. cattle herders). The general idea is that each cattle herder will see all the benefits of adding one more cow to his herd, but the resulting drawback (depletion of the grazing pasture) is a cost shared by all.
Although I was familiar with the phrase and the idea, I had never read the original essay that it came from. In 1968 Science magazine published Garrett Hardin's essay titled The Tragedy of the Commons, which in a rare example of electronic availability of pre-Internet content, is available online in its full form.
What I did not realise is that the article is not actually about cows. The article is about people, specifically humans, and the commons is the world in which we live. The article is about the population explosion. In 1968, the population of the world was somewhere between 3.3 and 3.7 billion. Today it is estimated to be 6.7 billion, nearly double the number of people from the time the article was written. From the conclusion of the essay:
The most important aspect of necessity that we must now recognize, is the necessity of abandoning the commons in breeding. No technical solution can rescue us from the misery of overpopulation. Freedom to breed will bring ruin to all.
The essay suggests that the freedom to breed must be curtailed if we, as the occupiers of this finite planet, are to survive and prosper. "[I]t is the role of education to reveal to all the necessity of abandoning the freedom to breed." If you have not yet read this essay from start to finish, go do so now. It's not a quick read, but it's not something we can ignore.