The geography of rapid population growth has narrowed dramatically over the past 50 years. In the 1960s, high growth rates were common across Asia, Latin America, and Africa. Today, only Sub-Saharan Africa maintains growth rates above 2.5%, while most of Asia has fallen to 0.5-1% and Latin America is approaching replacement level. This concentration means that Africa's share of global population will rise from 17% today to roughly 25% by 2050.
The Sahel countries at the top of this ranking face a particularly challenging set of circumstances. Niger, with growth near 3.8%, will see its population roughly triple from 25 million to 70+ million by 2050. This is happening in an arid, landlocked, conflict-prone region with limited agricultural potential and some of the weakest institutions on the continent. The mismatch between demographic expansion and economic capacity is severe.
The demographic transition theory suggests that fertility declines follow development: as incomes rise, education (especially female education) expands, and child mortality falls, families choose to have fewer children. This transition has occurred in every region of the world — including parts of Africa — but is proceeding more slowly in the Sahel than historical precedents would predict.
The policy implications are urgent. Investment in female education has the strongest documented effect on fertility reduction: each additional year of female schooling reduces fertility by roughly 0.3 children. Access to family planning services, reduction of child marriage, and expansion of women's economic opportunities are complementary interventions that accelerate the transition.