Sharing Our Planet:
the Global Commons
The global commons refers to shared things like oceans, water, forests—things we all need but that can end up abused through an implacable logic that has been called, after a 1968 article by Garrett Hardin, "the tragedy of the commons." 1 In a nutshell: in medieval Britain, a village's commons served as shared pastureland for herdsmen. For any one herdsman, to graze one more sheep produces a benefit to him of, say, +1. But there is a cost, as this additional animal will worsen the overgrazing of the commons. Because that cost, however, is shared with all the other herdsmen, it amounts to far less than -1 for our herdsman. And so he goes and adds the sheep.
And herein lies the tragedy: each herdsman has the same incentive to add sheep after sheep, until the land is so badly overgrazed that sheep raising becomes impossible. What has happened? Simply, the village community has failed to recognize that each herdsman's individual interest conflicts with the common interest. The community has failed to manage the commons from a communal standpoint.
The six global issues described below have something to do with that same failure, with the world not quite recognizing that our climate, biodiversity, forests, fisheries, fresh water resources, and oceans need to be managed from a communal, that is, global standpoint.