Who Guards the Pasture?
1In 1968 the ecologist Garrett Hardin published an essay that gave a lasting name to an old worry. He asked readers to picture a pasture open to every herder in a village. Each herder receives the full benefit of adding one more animal to the field, while the cost of the extra grazing, a slightly thinner pasture, is shared by everyone. Following this logic, every herder keeps adding animals until the grass is gone. Hardin called the outcome "the tragedy of the commons," and he concluded that shared resources must either be divided into private property or placed under the control of a government.
2For years the argument was taught as though it described a law of nature. Fisheries collapsed, forests were cleared, and water tables dropped, all seemingly confirming that people who share a resource will ruin it. Yet some researchers noticed that the story fit poorly with what historians and anthropologists had recorded. Many communities had shared grazing land, irrigation water, or fishing grounds for centuries without destroying them.
3The political economist Elinor Ostrom spent much of her career studying such cases. She and her colleagues examined mountain villages in Switzerland whose residents had jointly managed summer pastures for generations, irrigation systems in Spain and the Philippines run by the farmers who used them, and coastal fisheries in which local fishers decided among themselves who could fish where and when. In 2009 she became the first woman to receive the Nobel Prize in economics, largely for showing that the choice is not limited to private ownership or government control.
4Ostrom did not claim that every shared resource is managed well. Instead, she looked for the features that separated lasting arrangements from failed ones. Successful groups, she found, tended to have clear boundaries, so that everyone knew who had a right to use the resource. Their rules fitted local conditions; a limit that made sense for a dry valley would not suit a wet one. The people bound by the rules usually had a voice in changing them. Users watched one another, or hired monitors who answered to them, and penalties for breaking a rule began small and grew only for repeated offenses. Finally, the groups had inexpensive ways to settle disputes, and outside authorities respected their right to organize.
5Graduated penalties reveal something that Hardin's model left out. In his pasture, herders never speak to one another; each one calculates alone. In real villages, users are neighbors who expect to deal with each other for years. A herder caught overgrazing once might simply be reminded of the rule, a gentle response that keeps an honest mistake from turning into a feud. Because people know they are being watched, and that the community will not overlook a pattern of cheating, most choose to comply.
6None of this means that Hardin was entirely wrong. When users are strangers, when they cannot communicate, or when a resource is so vast that no group can monitor it, his grim forecast often comes true. The open ocean beyond national waters is a frequently cited example. Ostrom's contribution was to turn a seemingly universal law into a question about conditions: under what circumstances can people who share a resource govern it themselves?