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Climate Change and the Structure of Intergenerational Justice

Lucas Stanczyk

How quickly should the world reduce its greenhouse gas emissions? On the one hand, unless dramatic reductions in greenhouse gas emissions are put in place quickly, then millions of people in the future are likely to suffer climate-change induced catastrophes, including deaths from extreme weather, drought, famine, disease, and migration-induced widespread human conflict. On the other hand, if the present generation effects drastic emissions reductions quickly, then the rate of global economic growth is almost certain to fall significantly in the short-run. As a result, there will be millions of additional premature deaths from prolonged hunger and disease in the developing world, where billions continue to lack adequate nutrition, sanitation, medical care and even electricity. So, how quickly should the world reduce its greenhouse gas emissions? And what is the right approach to thinking about this question?

In this paper, I would like to explain why I think the dominant approach to this question will have to be rejected, and to outline the structure of what I have come to think is the correct one. Among policymakers, the dominant approach to thinking about the optimal emissions pathway continues to be normative welfare economics. However, as currently conceived and practiced, welfare economics is not suitable for settling how quickly to reduce our greenhouse gas emissions. My discussion will highlight two key issues. First, because of the non-identity problem, it is not true that our runaway emissions are inefficient. Therefore, the goal of securing greater efficiency cannot actually recommend significantly cutting our runaway emissions. Second, the approach that economists are wont to and do fall back on—subjective preference-satisfaction sum-total utilitarianism—shipwrecks on variants of the Repugnant Conclusion.

There is nonetheless a solution to both of these problems. However, it requires parting ways with the dominant approach. More precisely, we should reject the idea that what we owe to (present or future) people is to maximize the sum of welfare. Instead, we should think of our duties of intergenerational justice as requiring us to preserve the social and environmental basis of just or rights-respecting institutions. Finally, I will argue that thinking about intergenerational justice in this way allows us to side-step the non-identity problem. Even in the many cases in which our runaways emissions will not actually harm any unborn future people, we can still say that at all times humanity is subject to a suitably high environmental conservation standard.