World faces drastic fall in fertility rate: Lancet study

The research has found that by 2100, 97% of all countries will have a total fertility rate of lower than 2.1 births per woman

The world is facing a stark demographic divide as fertility rates plummet for most countries but remain high across sub-Saharan Africa, dramatically reshaping the global population landscape by the end of the century, according to a new study, among the largest such new forecasts.

A lab technician puts fertilised egg under the microscope at a fertility laboratory. (Getty Images/iStockphoto)

The research, published early on Thursday in the journal The Lancet, provides forecasts on global fertility and birth patterns through 2100. It has found that by 2050, three-quarters of nations will have fertility rates below 2.1 births per woman -- a number required to sustain generational replacement of population. By 2100, 97% of all countries will have a total fertility rate (TFR) of lower than 2.1.

“We are facing staggering social change through the 21st century,” said senior author professor Stein Emil Vollset of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington. “The world will be simultaneously tackling a ‘baby boom’ in some countries and a ‘baby bust’ in others.”

The total fertility rate -- the average number of children a woman gives birth to -- has fallen by more than half since 1950, from around five children per woman to 2.2 in 2021. While over half of countries were below the replacement rate of 2.1 children in 2021, fertility rates remain high in many low-income nations, particularly in sub-Saharan Africa.

Globally, the total fertility rate is predicted to decline further to around 1.6 by 2100, with only six countries expected to have rates above replacement level: Samoa, Somalia, Tonga, Niger, Chad and Tajikistan.

In contrast, the fertility rate is projected to drop below one child per woman for 13 countries by 2100, including Bhutan, Bangladesh, Nepal and Saudi Arabia.

In India, TFR as of 2021 was estimated to be at 1.91 and by 2050, this number was projected to drop to 1.29 by 2050 and further to 1.04 by 2100, the study said.

“Tumbling fertility rates are a success story, reflecting better contraception but also many women choosing to delay or have fewer children,” Vollset said.

The trends point largely to two implications. First, most middle- and high-income countries will be hit by unseen challenges as their TFR plummets. Populations here will shrink, reducing the workforce, at a time when swelling aging populations will present “enormous challenges to economic growth” and create a “growing burden on health and social security systems”.

In contrast, the region of sub-Saharan Africa is projected to account for over half (54%) of all global births by 2100, up from 29% in 2021, a trend the report described as a potential “humanitarian catastrophe” given the region’s limited resources and challenges like climate change.

In 2021, around 29% of global births occurred in sub-Saharan Africa. The study forecasts that share will balloon to over half of all births by 2100, around 40 million annually, as the region struggles with limited resources and growth stressers such as climate change.

“A large challenge for countries in sub-Saharan Africa is to manage risks associated with burgeoning population growth or risk potential humanitarian catastrophe,” said study co-lead author Dr Austin E Schumacher. “The huge shift in numbers of births underscores the need to prioritize this region.”

Solutions like improving access to modern contraception and female education could help accelerate declines in fertility rates, the study found. If global targets for universal education and contraceptive access were achieved by 2030, fertility rates in sub-Saharan Africa in 2050 could be reduced from around 2.7 to 2.3 children per woman.

For low-fertility nations, the study examined potential pro-natal policies offering financial incentives and support for childrearing. While these could slightly raise birth rates, most countries would remain below replacement levels.

“There’s no silver bullet,” said study co-author Dr Natalia V. Bhattacharjee. “Social policies may provide a small boost, but most countries will remain below replacement levels.”