Numbers Don't Lie: 71 Things You Need to Know About the World

by Vaclav Smil

The replacement level of fertility is that which maintains a population at a stable level. It is about 2.1, with the additional fraction needed to make up for girls who will not survive into fertile age. No country has been able to stop the fertility decline at the replacement level and achieve a stationary population. An increasing share of humanity lives in societies with below-replacement fertility levels. In 1950, 40 percent of humanity lived in countries with fertilities above 6 and the mean rate was about 5; by the year 2000, just 5 percent of the global population was in countries with fertilities above 6, and the mean (2.6) was close to the replacement level. By 2050, nearly three-quarters of humanity will reside in countries with below-replacement fertility. This nearly global shift has had enormous demographic, economic, and strategic implications. European importance has diminished (in 1900 the continent had about 18 percent of the world’s population; in 2020 it has only 9.5 percent) and Asia has ascended (60 percent of the world total in 2020), but regional high fertilities guarantee that nearly 75 percent of all births during the 50 years between 2020 and 2070 will be in Africa.