By Posner, Eric A.; Sunstein, Cass R.
Regulation , Vol. 31, No. 1
Climate change raises serious questions of science and economics, but it also raises questions of justice. The United States has been the world's leading contributor to the problem, and it is also the wealthiest nation on the face of the earth. Because of its past contributions, does the United States owe remedial action or compensation to those nations, or those citizens, most likely to be harmed by climate change?
Questions of corrective justice are entangled with questions of distributive justice. Because of its wealth, should the United States be willing to sign an agreement that is optimal for the world as a whole--but not optimal for the United States?
Our goal here is to answer those questions. To motivate the analysis and to put those arguments in their starkest form, we start with two assumptions: First, the world, taken as a whole, would benefit from an agreement to reduce greenhouse gas emissions. Second, the costs and benefits of emissions reductions differ greatly across nations, and some nations--above all the United States--would not benefit, on net, from the agreement that would be optimal from the world's point of view. If the United States unilaterally reduced its own greenhouse gas emissions significantly, it would impose significant costs on itself while producing few benefits to its citizens or even to the world. While a global agreement would benefit the world (our first assumption), its costs and benefits will be radically different across nations. The recent discussions in Bali, showing dramatic divisions across nations, are impossible to understand without appreciating this point.
Suppose, for example, that the world settled on a specified carbon tax--say, $70 per ton. Such a tax would be likely to impose especially significant costs on the United States simply because its per-capita emissions rate is so high. Suppose, in addition, that the United States is not as vulnerable as many other nations to serious losses from climate change and that its expected damage, in terms of health, agriculture, and more, is comparatively low. If so, the United States might be a net loser from a specified worldwide carbon tax even if the world gains a great deal. Perhaps the optimal carbon tax for the world would be $70 per ton, but the United States would do better with a worldwide carbon tax of $30 per ton, or $20 per ton, or even $10 per ton.
We accept the view that in many domains, resources should be redistributed from rich nations and rich people to poor nations and poor people. Such redistribution might well increase aggregate social welfare because a dollar is worth more to a poor person than to a wealthy one. But as we shall see, significant greenhouse gas reductions are a crude and somewhat puzzling way of attempting to achieve redistributive goals. We stipulate that when people in one nation wrongfully harm people in another nation, the wrongdoers have a moral obligation to provide a remedy to the victims. But the application of standard principles of corrective justice to problems of climate change runs into serious problems.
These conclusions should not be misunderstood. We agree that an international agreement to control greenhouse gases would be a good idea. We would not object if the United States showed a degree of altruism in such an agreement, conferring benefits on poor nations at its own expense. The recent agreement in Bali, by which wealthy nations agreed to provide financial and technological assistance to developing ones, might reflect such altruism on the part of at least some wealthy nations. Our goal is only to show that, contrary to widespread beliefs, standard ideas about distributive or corrective justice poorly fit the climate change problem.
To understand the issues of justice and the motivations of the various actors, it is important to appreciate the disparities in emissions across nations. We do not have clear data on the costs of emissions reductions for different nations, but it is reasonable to predict that the largest carbon emitters would bear the largest burdens from (say) a worldwide carbon tax. …