The Tragedy - 40 Years Later

“Picture a pasture open to all,” wrote ecologist Garrett Hardin in the December 13, 1968 issue of Science. According to Hardin, each herdsman seeks to maximize her gain by keeping as many cattle as possible on the field: the famous “tragedy of the commons.”

As climate concerns mount, let's note that the planetary atmosphere is not unlike Hardin's pasture. Into this global commons, each of us contributes, not cattle, but a share of greenhouse gases. We enjoy the utility of each carbon-powered car trip or manufactured item or temperature-controlled environment. But the cumulative effects of seemingly rational choices risk macro-economic madness.

Climate scientist James Hansen warns that atmospheric greenhouse gas concentrations should be stabilized at or below 350 parts per million. This figure addresses what ecological economist Herman Daly calls the scale question; it sets a target for the carrying capacity of the atmosphere. Other economists focus on the allocation question, meaning the comparative efficiencies of, say, a carbon tax versus a cap-and-trade system. Probably most thorny, though, is the distribution question. Whose cows – whose CO2 molecules – get to inhabit this pasture?

The dilemma, as Hardin reassessed 30 years after his original essay, is not that the atmosphere is a commons, but that it is an unmanaged commons, an open-access regime. “To judge from the critical literature,” he wrote in the May 1, 1998 issue of Science, “the weightiest mistake in my synthesizing paper was the omission of the modifying adjective ‘unmanaged’.”

How might societies reach a comprehensive agreement for management of the global atmospheric commons? As efforts in Kyoto, Bali and now Poznan, Poland demonstrate, it will not be easy. (See today's Dot Earth.)

Which disciplines, what areas of expertise, might provide guidance or leadership?

Political scientist (and Resilience Alliance board member) Elinor Ostrom has spent decades researching the management of common-pool resources, both in controlled studies and in societies around the world. She finds that humans hold some significant advantages over Hardin's theoretical herdsmen. Most importantly, people can talk with one another. And, when it comes to solving social dilemmas, communication can make all the difference.