The world’s population, on course for long-term decline

The Population Division of the United Nations Department of Economic and Social Affair (UN DESA/POP) recently released new population estimates and projections for the world, and 237 countries or areas and various groupings thereof.^[1] Covering the period 1950-2023 and based on various existing sources of information,^[2] the estimates provide a highly instructive insight into population dynamics and the predominant trends at work. The outlook covers the period 2024-2100 and, like the previous ones, is based on the assumption of continued human progress, according to which the trend towards higher life expectancy can only continue, while fertility can only decline where it is highest.^[3]

The methodology used to produce these prospects is even more complex than previously, but it still assumes the total independence of key factors in demographic change. So, whether a country’s net migration (immigrants minus emigrants) is zero or several million, this is assumed to have no effect on fertility: as if immigrant women instantly adopt the fertility behaviours of the host country. Furthermore, as in previous versions, future demographic trends are anticipated without taking local realities into consideration or reflecting on the conditions for their occurrence.

A pure in vitro demography exercise, then, illustrating — to a greater or lesser degree, according to the various variants — the theory of global demographic convergence, the UN’s recent population prospects are no more designed to describe the future demographics of the world than are previous ones. They are simply intended to outline a few possible scenarios, all else being equal, and to provide food for thought on the long-term issues and deadlocks associated with certain combinations of factors.