The scale of this expansion is unprecedented: while Asia’s population will have multiplied by four in the same period, Africa’s will have multiplied by ten. The result is what demographer Richard Cincotta calls “chronic youth”: 40% of Africans are children under 14, and in most African countries the average age is under 20.

African mothers will have about 450 million children in the 2020s. By the 2040s, that number is expected to reach over 550 million, approximately 40% of all children born in the world over that period. 

Globally, the number of births is at its highest point in history-140 million per year-and is unlikely to decline in the next two or three decades.