A Glimpse into the Future: The World’s Population in 2100 and beyond

Anne Goujon, International Institute for Applied Systems Analysis (IIASA)
Samir KC, IIASA

In 2023, the Wittgenstein Centre released the third round of global population projections for 200 countries, incorporating data on educational attainment and scenarios aligned with the Shared Socioeconomic Pathways (SSPs), which are widely used within the environmental and climate change community. While the update primarily involved adjustments to certain short-term assumptions based on recent observed changes, it largely retained the mid- and long-term assumptions. Nevertheless, this led to an increased projected global population of 9.9 billion by 2100 under the middle-of-the-road scenario (SSP2), with a delayed peak around 2080 at 10.1 billion. The most notable difference from previous rounds was due to a more rapid decline in child mortality and a slower fertility transition in sub-Saharan Africa and South Asia over the last decade, contributing to higher population growth and a larger absolute population by 2100. These trends pose significant challenges for society, the environment, and resource availability, and also highlight the need for future updates to reflect changes in assumptions related to fertility, mortality, and migration. We address these uncertainties by extending projections to 2300, highlighting the long-term consequences of current assumptions and the potential need for refinement in future updates.

Keywords: Population projections, forecasts, and estimations, Data and Methods, Population and Development, Human Capital, Education, and Work

See extended abstract.