The global human birthrate is projected to undergo a significant contraction throughout the forthcoming century, with more than two-thirds of nations anticipated to experience population decline within a mere quarter-century.
“These impending shifts in procreation rates and live births will fundamentally reshape the global economic landscape and the international distribution of power, necessitating substantial societal reorganization,” explains Natalia Bhattacharjee, a demographic statistician affiliated with the Institute for Health Metrics and Evaluation (IHME) in the United States.
In 2018, prior investigations indicated a reduction in fertility rates across half of the world’s populations, and this downward trend persists.
By the year 2050, the latest research forecasts that the populations of 155 out of the 204 surveyed countries and territories will be producing fewer offspring than are required to sustain a stable demographic level.
Projections reveal that by 2100, this figure will escalate to 198 countries and territories where birth rates will fall below mortality rates. Nations such as Bhutan, Bangladesh, Nepal, and Saudi Arabia are expected to see rates drop below one child per female. By that juncture, the sole countries anticipated to maintain birth rates above the threshold necessary for population perpetuation (a minimum of two births per female) are Samoa, Somalia, Tonga, Niger, Chad, and Tajikistan.
Consequently, the authors assert that in the absence of proactive migration strategies, human populations in regions characterized by low birth rates will inevitably contract.
However, is this development inherently detrimental? In numerous nations, diminished birth rates are a consequence of improved circumstances for women and families in general.
“In many respects, declining fertility rates represent a triumph, reflecting not only enhanced access to readily available contraception but also a growing number of women opting to postpone childbirth or have fewer offspring, alongside expanded opportunities for education and professional pursuits,” notes senior author and biostatistician Stein Emil Vollset, who is also a member of the Future Health Scenarios forecasting unit.
During the 1950s, the average number of children born per female was just under five, contrasting sharply with just over two children per female recorded in 2021.
Nevertheless, the researchers highlight that the ramifications of such a profound demographic transformation will be contingent upon its management and the geographical distribution of populations. Currently, they contend, the global community is inadequately prepared for the impending changes.
The study indicates that the majority of newborns over the coming decades will originate from low- and lower-middle income countries.
Chad and Niger are projected to exhibit the highest fertility rates globally in 2050, with Samoa and Tonga slated to hold this distinction by 2100.
By 2100, Africa is expected to account for half of all births worldwide, having already contributed one-third of global births in 2021.
“The world will concurrently confront a ‘baby boom’ in certain regions and a ‘baby bust’ in others,” observes Vollset.
“While a significant portion of the globe grapples with the formidable challenges to economic expansion posed by a shrinking labor force and the complexities of funding and providing care for aging populations, many of the most resource-constrained nations in sub-Saharan Africa will be contending with the task of supporting the youngest, most rapidly expanding demographic segment on the planet in environments marked by considerable political and economic instability, heat stress, and strained healthcare systems.”
The authors emphasize that “ethical and efficacious immigration frameworks, coupled with international collaboration,” will be paramount in navigating the population declines many nations are poised to experience.
“Once virtually every nation’s population begins to contract, reliance on open immigration will become essential for sustained economic growth,” states Bhattacharjee. “Nations in sub-Saharan Africa possess a critical asset that increasingly aging societies are losing – a youthful populace.”
However, the researchers caution that it will be imperative to ensure that migration flows are not unidirectional.
“The ongoing migration of skilled professionals to high-income, low-fertility economies – an phenomenon known as brain drain – can also inflict severe damage on the economies of the countries from which these workers depart,” they articulate.
While acknowledging certain significant constraints to the study, such as the inclusion of data from the anomalous COVID-19 period, the forecasts are grounded in pivotal fertility determinants – including educational attainment, contraceptive accessibility, child mortality rates, and urbanization – alongside data extending back to the 1950s, and exhibit a relatively high degree of predictive certainty across all countries.
This research originated from the Global Burden of Disease, Injuries, and Risk Factors Study 2021 and received financial backing from the Bill & Melinda Gates Foundation.
This investigation is published in The Lancet.
