The world’s total fertility rate has been cut in half since 1950, but the population is still rising, according to a study published Thursday in The Lancet.
Population growth rate from 2010 to 2017, by location, Source The Lancet, 10 November 2018
The total fertility rate — or the average number of children a woman would have if she lived through all her reproductive years — declined from 4.7 live births in 1950 to 2.4 in 2017.
Meanwhile, the global population has nearly tripled since 1950, from 2.6 billion people to 7.6 billion, the report says. An average of nearly 84 million people have been added to the Earth’s population every year since 1985.
“As women have gotten more educated and participate more in the workforce and they get access to health services, no surprise, fertility has come down tremendously,” said study author Dr. Christopher Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington. “And it comes down faster in younger women.”
Other factors have been shown to predict falling fertility rates, including better infant survival rates and later marriage.
“The age at which women are getting married is increasing,” said Dr. James Kiarie, coordinator for the World Health Organization’s Human Reproduction Team in the Department of Reproductive Health and Research.
“Marriage is one of the biggest drivers of having children all over the world,” said Kiarie, who is not an author on the new report.
While total fertility rates fell across all 195 countries and territories in the data, they were split roughly down the middle between those below replacement level and those above, Murray said. “Replacement” describes the total fertility rate “at which a population replaces itself from generation to generation, assuming no migration,” which comes out to about 2.05 live births, the authors say.
For example, a woman in Cyprus had one child on average in 2017, while a woman in Niger had 7.1. This range is lower than 1950’s, in which total fertility rates ranged from 1.7 live births in Andorra to 8.9 in Jordan.
“The world is really divided into two groups,” Murray said. “In a generation, the issue’s not going to be about population growth. It’s going to be about population decline or relaxing immigration policies.”
In countries that want to boost fertility rates, the creation of financial incentives for families, including parental leave, has been shown to have a small effect, Murray said. Only 33 countries, largely in Europe, were falling in population between 2010 and 2017, according to the report.
“The country that’s probably the most concerned about this already is China, where the number of workers is now starting to decline, and that has an immediate effect on economic growth potential,” Murray said. “In a place like India — that is still above replacement but very soon going to be below replacement fertility — that’s just such a dramatic change.”
That doesn’t mean the global population will soon reverse course. A United Nations report last year predicted that the world population would swell to 9.8 billion by 2050 and 11.2 billion in 2100. That report forecast that over half of the expected growth between 2017 and 2050 is likely to occur in Africa.