“Take Taiwan,” says Birt. “Its fertility rate has gone from about 7 in 1950 to less than 1 today. This trend applies to any country on the development escalator. It’s inevitable.” As a country develops, initially its death rate declines because of a rising standard of living and better medical care. Next, almost automatically, fertility goes down. “Japan got on the escalator first, and the emerging countries, like Brazil, will get there,” Birt continues. “The religion of the country is irrelevant. It’s happening now in Iran. It’s happening in Catholic countries that oppose birth control, like Italy and Spain. In Mexico the fertility rate is under 3, approaching replacement level.” The replacement rate is the number of children that the average woman must produce in order to replace herself and her mate. Demographers normally define the replacement rate as 2.1 children, the 0.1 increment allowing for infant mortality. It is a pivotal number, indicating that a population is stable, not expanding, and very likely to shrink. Among the 222 countries and territories in the world, two-thirds now have fertility rates below 3, while one-third have slipped under 2 and have begun to contract. Japan, the poster child for extreme trends in aging and fertility, is projected to lose a third of its population in the next 50 years. The most populous nation, China, has a fertility rate of 1.5. Though China’s strict one-child-per-couple decree obviously has holes, the policy is having the desired result. India, the second most populous nation, has brought down its growth to 2.6 children per woman. The United States stands at the cusp of population decline because American females are having an average of only 2.06 children apiece.
In those figures lies the turnabout in world population that Glick predicts, and also its senescence, because when people are taken off the population escalator—at the front end, by not being born—those already on it become more conspicuous as they near the top. There is no stopping the process. “That’s why we say demography is destiny,” Glick remarks. “There’s only one exit: death.” Birt describes a favorite graphic of his, derived from a 2007 United Nations publication. He calls it “Solving for X” because of the problem it raises for the world’s health-care systems. Two lines are crossing, the percentage of people over 65 and the percentage under 5. Back in 1950, children predominated in the world; in 2050 the seniors will be on top. “The percent over 65 and under 5 are trading places,” Birt says. “We’re almost at the X spot.” The forecast date for global X to occur is 2017, but each country will arrive at the transition at a different time. “Japan blasted through its intersection years ago,” he notes.
Was there a single factor to account for this world-shaking reversal? “Yes,” Glick says. “You start educating girls.” Birt agrees. “You start educating women, and they delay marriage and have fewer children,” he says. “It’s all due to not having children in societies that let women loose.”