Abstract
Contrary to political and philosophical consensus, we argue that the threats posed by climate change justify population engineering, the intentional manipulation of the size and structure of human populations. Specifically, we defend three types of policies aimed at reducing fertility rates: choice enhancement, preference adjustment, and incentivization. While few object to the first type of policy, the latter two are generally rejected because of their potential for coercion or morally objectionable manipulation. We argue that forms of each policy type are pragmatically and morally justified tools for preventing the harms of global climate change.