In an influential 1968 essay, ecologist Garret Hardin popularized the expression “tragedy of the commons.” His example was a village pasture that anyone could use. Sheepherders, Hardin argued, would rationally decide to graze as many animals that they owned as they could on the commons, since they would reap the benefits from each additional animal while the costs of their grazing were shared by all. But if all herders did the same, the pasture would be overgrazed and destroyed.

The village pasture in Hardin’s example can be interpreted to represent the environment in general—a sort of global commons that is used jointly by all and in which the activities of one can affect many. For instance, the air we breathe is a “commons” that nobody owns but everybody uses. A factory...