Africa will dominate global population growth in the 21st century. Almost 1bn people, or 13 per cent of the world’s population, live in sub-Saharan Africa today. That number will more than double by 2050 and 4bn people (or 36 per cent of the world’s population) could live in the region by 2100, according to a projection last month by the UN Population Division. The main reason for the rapid growth is a sharp decline in infant and child mortality, with no associated reduction in birth rates. Today, sub-Saharan women have five children on average, compared with 6.7 in 1970. Growing populations in the sub-Saharan region will influence societies, economic outcomes and geopolitics. In addition, the expected effects on food and water security (exacerbated by climate change) will be unprecedented. These trends will impact not only the region but the rest of the world. Europe appears to be particularly vulnerable as migration from sub-Saharan Africa is likely to intensify in coming decades. The good news is that African demographics appear to be commanding more international attention. The G20-Africa Partnership Conference, held in Berlin in June, focused specifically on Africa’s population boom. The G20 Summit in Hamburg this weekend will also address Africa’s population size and highlight the need for better employment opportunities. Sub-Saharan Africa is at a crossroads regarding the potential to capture a demographic dividend — an economic surplus triggered by the decline in birth rates, a decrease in the number of young dependants and an increase in the proportion of working-age adults. But the pressing policy question is whether the region can replicate the conditions that enabled several east Asian countries to prosper from their own demographic dividends from the early 1960s to the 1990s.