The Collapse of Global Fertility Rates: A Divided Vision for Humanity’s Future

While some celebrate falling fertility rates as a success, others warn of the existential dangers posed by population collapse.

by Nicolas Hulscher, MPH

The total fertility rate (TFR) of a population is the “average number of children that are born to a woman over her lifetime, if they were to experience the exact current age-specific fertility rates (ASFRs) through their lifetime, and they were to live from birth until the end of their reproductive life.” In May 2024, the GBD 2021 Fertility and Forecasting Collaborators published a study in The Lancet titled, Global fertility in 204 countries and territories, 1950–2021, with forecasts to 2100: a comprehensive demographic analysis for the Global Burden of Disease Study 2021. They found the following as summarized by the Institute for Health Metrics and Evaluation:

By 2050, over three-quarters (155 of 204) of countries will not have high enough fertility rates to sustain population size over time; this will increase to 97% of countries (198 of 204) by 2100.

Pronounced shifts in patterns of livebirths are also predicted, with the share of the world’s livebirths nearly doubling in low-income regions from 18% in 2021 to 35% in 2100; and sub-Saharan Africa accounting for one in every two children born on the planet by 2100.

In low-income settings with higher fertility rates, better access to contraceptives and female education will help reduce birth rates, while in low-fertility, high-income economies, policies that support parents and open immigration will be vital to maintain population size and economic growth.

Authors warn that national governments must plan for emerging threats to economies, food security, health, the environment, and geopolitical security brought on by these demographic changes that are set to transform the way we live.