6.4 Collective Action Problems: The Problem Of Incentives - OpenStax

The Tragedy of the Commons60

The world’s resources are finite. In southern Africa in the 20th century, overhunting nearly led to the extinction of the black rhino.61 Many types of fish—including tuna, cod, and halibut, among others—are being pulled out of the ocean at commercially unsustainable levels.62 The climate is changing because humans are in effect using up the atmosphere’s capacity to absorb greenhouse gases.63

Whenever there is a resource that anyone within a group can tap, or exploit, that resource is a “commons.” Regarding fish and fishing, the oceans have been a commons. If anyone can withdraw water from a river, that river is a commons; likewise, if anyone can emit air pollution, the atmosphere is a commons.

Figure 6.12 Commercial fishing of tuna and other species can lead to a tragedy of the commons. (credit: “Tuna fish” by Motaz Altahir/Flickr, Public Domain)

In each of these cases, the same principle dominates. If anyone has access to the commons—whether that resource is the rhino grazing in Africa, the tuna swimming in the northern Atlantic, or the atmosphere—and that resource is scarce, then every individual has an incentive not only to take what they need but also to take as much as they want. Individuals have this incentive because they can sell this scarce resource (rhino horns, tuna fish) or because they benefit today without consideration of future consequences. If everyone took only what they needed, some renewable resources could become replenished. But if everyone has the incentive to take as much as they can, pretty soon those resources will be depleted. No one can access a resource that has been depleted. If everyone had shared, there may well have been enough to meet everyone’s long-term needs. In the paradox of the tragedy of the commons, those who seek to hoard resources ultimately have less even for themselves.

Bluefin tuna, highly valued for its use in sushi, carries a high price, and so commercial fisheries have strong incentives to catch as many of them as they can. Between the 1970s and the early 2000s, the Atlantic population of bluefins declined by an estimated 80 percent due to overfishing, and scientists warned that the species faced extinction unless the tragedy of the commons was averted.64 Though tuna became extinct in the Black Sea, primarily due to overfishing and other environmental pressures, strictly enforced catch quotas helped avert the tragedy in the Atlantic.65 Sadly, there are numerous other examples, such as overfishing in places like China and Chile, the depletion of freshwater resources in places like Australia and Saudi Arabia, and worsening traffic congestion in places like Los Angeles and Cairo, as roads are a scarce resource that can be overconsumed.

What Is the Tragedy of the Commons?

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This TED lesson uses a simple, step-by-step example to explain the tragedy of the commons.

Global climate change is perhaps the most pressing example of the tragedy of the commons.66 Tragedies of the commons could be prevented if everyone—especially those who take the most, whether individuals or countries—took less, but no single person or country has the incentive to do so.