Is global social welfare increasing? A critical-level enquiry

We assess whether global social welfare has improved in the last decades despite (or because of) the substantial increase in global population. We use for this purpose a relatively unknown but simple and attractive social evaluation approach called critical-level generalized utilitarianism (CLGU). CLGU posits that social welfare increases with population size if and only if the new lives come with a level of living standards higher than that of a critical level. Despite its attractiveness, CLGU poses a number of practical difficulties that may explain why the literature has left it largely unexplored. We address these difficulties by developing new procedures for making partial CLGU orderings. The headline result is that we can robustly conclude that world welfare has increased between 1990 and 2005 if we judge that lives with per capita yearly consumption of more than $1,248 necessarily increase social welfare; the same conclusion applies to Sub-Saharan Africa if and only if we are willing to make that same judgment for lives with any level of per capita yearly consumption above $147. Otherwise, some of the admissible CLGU functions will judge the last two decades' increase in global population size to have lowered global social welfare.