Global economic development is the key driving force behind the decline, as improved education, better access to contraception, and a reduction in infant mortality – meaning more children will survive into adulthood – all contribute.
“In many ways, tumbling fertility rates are a success story, reflecting not only better, easily available contraception but also many women choosing to delay or have fewer children, as well as more opportunities for education and employment,” said senior author Dr Vollset from the University of Washington.
The global fertility rate has already halved over the past 70 years, from around five children per female in 1950 to 2.2 in 2021.
The sharp drop in fertility will have “profound effects on populations, economics, geopolitics, food security, health, and the environment,” as countries grapple with an elderly population and heavily reduced workforce, according to the study.
Only 26 countries – including Angola, Uganda, Chad, and Somalia – are set experience population growth in 2100.
Whilst fertility rates are dropping across the board, the rate of decline in low and middle-income countries, particularly in sub-Saharan Africa, is projected to be much slower than the rest of the world.