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A school for small families
Thanks to education, global fertility could fall faster than expected
The world’s population in 2100 could be no higher than it is today
THE AVERAGE woman in Niger has seven children. The average South Korean has barely one. The future size of the world’s population depends largely on how quickly child-bearing habits in places like Niger become more like those in South Korea. If women in high-fertility countries keep having lots of babies, the number of people will keep swelling. The sooner they curb their fecundity, the sooner it will peak and start falling.
Swell: v. Become or make greater in intensity, number, amount, or volume.
eg: the city's population was swollen by refugees.
Fecundity: n. The ability to produce an abundance of offspring or new growth; fertility.
The UN projects that fertility will fall gradually and that lifespans will increase, so the world’s population will rise from 7.7bn today to 11.2bn by 2100. (This is its best estimate; the UN says it is 95% confident that the true figure will lie between 9.6bn and 13.2bn.) Opinions are divided over the effects of such growth. For some, a more crowded planet will be an environmental disaster. For others, those billions of extra brains will help humanity devise ever more cunning solutions to its problems.
eg plants have evolved cunning defences.
But what if the projection is wrong? Some demographers argue that the UN underestimates how fast fertility will decline. It has already tumbled dramatically. Data from before the Industrial Revolution are spotty but evidence from countries that kept good records, such as America, suggests that a typical woman had seven or more children. By 1960 the global fertility rate had fallen to five. Today it is 2.4. This is only just above the “replacement rate” of 2.1, at which the population remains stable, with each generation replacing itself but no more. (The rate is more than two because not every baby grows up to be able to have children.)
Nearly all rich countries have sub-replacement fertility rates: the OECD average is 1.7. Middle-income countries are close, at 2.3. Only in poor countries is fertility still high enough to fuel rapid population growth. In sub-Saharan Africa it is 4.8; in “heavily indebted poor countries” (as the World Bank calls them) it is 4.9. Pre-industrial fertility rates persist only in the poorest parts of the poorest countries.