Why sub-Saharan Africa might exceed its projected population size by 2100
Level 5 - mechanism / opinion, no new human data
Commentary and expert perspective on demographic modeling studies (Level 5 by design analogy)
OpenAlex W3042506090 · doi:10.1016/s0140-6736(20)31522-1
What was done
The author analyzed the 2017–2100 global population forecasting models from the Institute for Health Metrics and Evaluation (IHME). The commentary critically contextualized IHME's reference and alternative scenarios—driven by completed cohort fertility at age 50, educational attainment, and met contraceptive need—specifically examining the socioeconomic, developmental, and infrastructure implications for sub-Saharan Africa compared to United Nations Population Division (UNPD) forecasts.
What was found
The IHME reference scenario projected global population to peak at 9.73 billion (95% UI 8.84–10.9) in 2064 and fall to 8.79 billion (95% UI 6.83–11.8) by 2100. Alternative scenarios ranged from 6.29 billion (Sustainable Development Goal pace) to 13.6 billion (slower education and contraceptive pace). While several regions face substantial declines (>50%), sub-Saharan Africa's population is forecasted to triple to 3.07 billion (95% UI 2.4–3.84) by 2100, shifting from 13% of the global population in 2017 to 35% in 2100 (compared to UNPD's 3.78 billion projection). The paper notes historical UNPD 2050 forecasts for the region were repeatedly revised upward (1.52 billion in 1998 to 2.12 billion in 2019) and highlights an existing annual infrastructure financing shortfall of 52%–64% (US$130–170 billion).
Why it matters
While global demographic debate often focuses on declining fertility in high-income regions, sub-Saharan Africa faces unprecedented population expansion requiring a threefold increase in infrastructure and basic services simply to maintain current living standards.
Limits
This is a commentary and narrative review rather than primary empirical research. Findings depend on long-term demographic forecasting models with wide uncertainty intervals that extrapolate educational trends, contraceptive access, and fertility patterns across an 80-year horizon.
Cited by
- context Global human population is projected to reach 11 billion people by the year 2100.