Population Ethics and Earth's Carrying Capacity

Sir Partha Dasgupta (Cambridge University)

Parental desires and needs in the face of socio-economic and ecological constraints are the basis on which economic demography has been built. Moral philosophers in contrast study population ethics, but shy away from characterising the constraints under which the ethics is to be put to work.

No system of ethics should be expected to yield unquestionable directives in all conceivable circumstances, even to the same person. If we are to arrive at satisfactory policies, a suitable accommodation has to be found for the economist's concerns, the environmental scientist's predilections, and the philosopher's sensibilities. In this lecture I put a broad version of Utilitarian population ethics to work on current estimates of Earth's carrying capacity. The population size and the average standard of living that the ethics commends is shown to be substantially different from what they are today. Plausible ranges of values for the ethical parameters point to a desirable population size that is considerably lower than the current 7.2 billion and an average living standard that is higher than the current per capita income of some 12,000 international dollars a year.