Previously published on The Economist.

But the education of more African girls means it might peak sooner than most people expect

By 2050, Nigeria is forecast to have 400m people, meaning it will overtake the United States as the world’s third-most-populous country. The starkness of this fact (its population is currently about 200m) illustrates the degree to which demography will shape Africa’s future. Nigeria’s growth is part of an extraordinary population surge across the continent, but there is controversy about whether it will continue or can be reined in. The answer to that question has serious economic and political implications.

Sub-Saharan Africa’s population is growing at 2.7% a year, which is more than twice as fast as South Asia (1.2%) and Latin America (0.9%). That means Africa is adding the population of France (or Thailand) every two years. Although Asia’s population is four times bigger, almost two children are born each year in Africa for every three in Asia. Most experts agree that, if it continues at its current growth rate, like Nigeria, Africa’s population will double by 2050. That would be 2.5bn people, meaning more than a quarter of the world’s people would be in Africa. Few question those figures because much of the growth is already baked into what demographers term “population momentum”—that is, Africa has so many women of childbearing age that even if most decided to have fewer babies today, the population would keep expanding.

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