Abstract

This chapter qualitatively lays out some of the ways that climate change impacts are evaluated in integrated assessment models (IAMs). Putting aside the physical representations of these models, it first discusses some key social or structural assumptions, such as the damage functions and the way growth is modeled. Second, it turns to the moral assumptions, including parameters associated with intertemporal evaluation and interpersonal inequality aversion, but also assumptions in population ethics about how different-sized populations are compared and how we think about distributing goods across or within times. The intention is to survey the morally important assumptions that go into estimates of the social cost of carbon, the marginal cost of an additional tonne of carbon dioxide to society.