Rejecting the Traditional Model
The claim that climate change is a tragedy of the commons (or prisoner’s dilemma) played out between nation states is pervasive in academia, policy, and the popular press. Nevertheless, I believe it involves a dangerous misdiagnosis.
Some reject the model as too pessimistic, claiming that game theory relies on false and morally problematic assumptions. Actual agents, they say, (whether people or nations) are not narrowly self-interested; and such claims have the effect of ruling out more generous motivations—and the possibility of ethical action—by definition. Consequently, the traditional model is not an appropriate guide to policy.
I agree that the usual motivational assumptions should be resisted, but not that this justifies rejecting game- theoretic methods. My first reason is that the basic approach is compatible with more generous motivational assumptions. For instance, agents often value others deeply, but nonetheless primarily in a self-referential or time-indexed way. For example, they value their own children or community, or their own time and place. Game theory helps to reveal how this can also result in tragedy (e.g., when anxious parents competitively “hothouse” their children).
My second reason is that game-theoretic models are often a good guide to what to expect when wider values are present but not adequately reflected in existing institutions, so that they play little role in how decisions are actually made. In such situations, the result picked out by narrow, self-interested, self-referential, or time-indexed motivations is often the natural “default.” This does not show that people lack wider values, only that there are no effective channels to register them, or at least that the channels available to narrower values are much more effective. Importantly, this seems plausible in the climate case, since markets and standard election cycles provide routes for short-term economic concerns to drive decision making that seem lacking for global, intergenerational, and ecological concerns. Game theoretic models thus help us to foresee the consequences of institutional failure.
Nevertheless, I maintain that we should reject the standard tragedy of the commons analysis of climate change. This is not because it is too pessimistic, but rather because it is overly optimistic. First, it obscures basic issues of international fairness. For instance, in framing the policy challenge as one of securing cooperation between parties through a process of self-i nterested bargaining, the standard model marginalizes important ethical issues, such as skewed vulnerabilities and background injustice. Such factors allow powerful bargainers to take advantage of the circumstances and create compound injustices (cf. the complaints of the Maldives and G77). Ignoring them leads policymakers to underestimate the real challenges they face.
Second, and even more importantly, the tragedy of the commons analysis ignores vital dimensions of the climate challenge, and in ways that threaten the integrity of the whole global storm approach. Most notably, the standard model conceives of climate change as essentially an international problem, under the assumption that the relevant parties are individual countries who effectively represent the interests of their populations in perpetuity. This assumption is dubious in general. As we shall see, it is especially reckless for climate change.