Partha Dasgupta’s book Time and the Generations: Population Ethics for a Diminishing Planet (2019) engages us in one of the most taboo issues in development debates: the environmental consequences of population. He asks what level of economic activity our planet can support and what that implies for the optimal global population. As a leading British-Indian economist, Dasgupta models how adverse externalities — poverty, degradation of the environment, resource stress — impact the economy and through his mathematical logic shows the importance of knowing optimum population numbers. [...]