Many have argued that climate change is the textbook example of a tragedy of the commons. Assuming that is correct, to make headway on climate change, we would expect an enforceable agreement that provides for global collective action. The tragedy of the commons assumes that those who cut back when others do not are—to use the formal language of game theorists—suckers. So, the last thing we would expect is a surge of unilateral action. Contrary to theory, for the past decade, unilateral climate action has flourished among governments, businesses, other organizations, and individuals.

Is the number of climate suckers growing exponentially, or is there more going on? This Article proposes an alternative explanation. A growing and substantial part of the climate crisis is not subject to the tragedy of the commons, allowing rational actors to take climate action because of their self-interests, not despite them.

While the ability to rely on unilateral action to make some climate progress unlocks exciting possibilities, effectively confronting climate change requires a better understanding of why unilateral actors act. This Article exposes the economic and political incentives that frequently drive unilateral action. Understanding the incentives of unilateral actors opens two promising inroads for climate action: strengthening unilateral action by playing to these incentives and building on unilateral action to make collective action more obtainable.