Recent global research led by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington School of Medicine, the 2021 Global Burden of Disease, Injuries, and Risk Factors Study (GBD), indicates the world is heading towards a future of low fertility rates. By 2100, over 97% of countries and regions will have fertility rates below the level needed for long-term population maintenance, yet many low-income countries, primarily in western and eastern sub-Saharan Africa, will continue to see population growth this century due to relatively high fertility rates. The findings were published in The Lancet.
"The world will face the simultaneous challenges of 'baby booms' in some countries and 'baby busts' in others. While most countries grapple with the severe challenges of a shrinking workforce to economic growth and finding ways to support an aging population, many of the poorest countries in sub-Saharan Africa will be striving to feed the world’s youngest and fastest-growing populations in some of the most politically and economically unstable, hottest, and most healthcare-strained locations," said Professor Stein Emil Vollset of the IHME.
Dr. Natalia V. Bhattacharjee, a principal researcher at the IHME, believes the impact of this situation is profound. The future trends in fertility rate and live birth patterns will fundamentally reshape the global economy and international equilibrium, making societal restructuring inevitable. With a fierce competition for migrants to maintain economic growth while the baby boom in sub-Saharan Africa continues to rise rapidly, a greater understanding of the challenges related to global migration situations and the world aid network becomes increasingly critical.
Researchers, using the latest methods to forecast mortality, fertility rates, their main driving factors, and live birth rates, estimate that by 2050, 155 out of 204 countries and regions (76%) will have fertility rates below the replacement level. By 2100, this number is expected to increase to 198 countries and regions (97%). This means that unless low fertility rates can be offset by ethical and effective migration activities, these areas will see a reduction in population size. Furthermore, policies that provide more support to parents and promote procreation can partially alleviate the low levels of fertility.
The study shows that over the past 70 years, the global total fertility rate has more than halved, dropping from an average of about 5 children per woman in 1950 to 2.2 in 2021. In 2021, more than half of the countries and regions (110 out of 204) had fertility rates below the population replacement standard of an average of 2.1 children per woman. Countries like South Korea and Serbia are particularly concerning, with total fertility rates of less than 1.1. However, for many countries in sub-Saharan Africa, fertility rates remain high—nearly double the global average, with an average of 4 children per woman in 2021. The Republic of Chad has the highest fertility rate in the world at 7.
By 2100, only 6 out of 204 countries and regions (Samoa, Somalia, Tonga, Niger, Chad, and Tajikistan) are expected to have fertility rates exceeding 2.1 children per woman.
"In many ways, the decline in fertility rates is a success story, reflecting not only better and more accessible contraceptive measures but also the choices many women make to delay or reduce the number of children they have, as they gain more education and employment opportunities," Vollset stated.
The study indicates that in the coming decades, the majority of children will be born in the world’s most resource-limited areas, with over 77% of live births expected to occur in low-income and lower-middle-income countries by the end of this century. By 2100, many countries in sub-Saharan Africa are expected to account for over half of the global live births, approximately 40 million.
"A major challenge for the highest-fertility countries in sub-Saharan Africa is how to manage the related risks of rapid population growth, which could lead to potential humanitarian crises," noted Dr. Austin E. Schumacher, an assistant professor at the University of Washington School of Medicine. "The significant changes in the number of newborns underscore the need to prioritize the sub-Saharan Africa region, work to mitigate the effects of climate change, improve healthcare infrastructure, further reduce child mortality rates, and take action to eliminate extreme poverty, ensuring that women's reproductive rights, family planning, and girls' education become a top priority for governments."
"These profound changes in future fertility rates reveal a clear population divide, with vastly different impacts on many middle- and high-income countries and low-income regions. This requires governments to implement safe and beneficial policies to create conditions that increase birth rates in some areas and decrease them in others. Time is precious, and efforts made now to manage population growth may only begin to show their effects after 2050," Schumacher pointed out.
Analyses suggest that in countries with higher fertility rates, concerted efforts to rapidly disseminate modern contraceptives and female education could help accelerate the decline in fertility rates and reduce birth rates. "While achieving these two widespread goals in all regions by 2030 may be somewhat unrealistic, it is clear that addressing the population explosion in high fertility countries largely depends on accelerated progress in girls' education and the protection of reproductive rights," Schumacher said. The research also examined the potential impact of pro-natal policies aimed at providing economic support and care for children and families on increasing the fertility rates of countries below replacement levels. Based on available data from countries that have implemented such policies, the findings indicate that while pro-natal policies may not raise fertility rates to replacement levels, they can prevent some countries from experiencing a steep decline in fertility rates.
Researchers suggest that for countries with low fertility rates, it is important to implement various combinations of policies that support individuals who wish to have children and provide more social benefits, such as improved quality of life, increased opportunities for women in the workforce, while also implementing open immigration policies.
Bhattacharje, for instance, cited social policies aimed at boosting birth rates such as extended parental leave, free childcare services, economic incentives, and additional employment rights, which may marginally increase fertility rates, but most countries are likely to remain below replacement levels.
Additionally, researchers highlighted limitations of the study, including reliance on existing best available data, but predictions are still constrained by the quantity and quality of past data, especially during the pandemic period of 2020-2021. They also noted that past trends do not necessarily predict future outcomes, and these fertility rate predictions largely depend on accurately estimating potential drivers of future fertility rates.
World Health Organization experts Gitau Mburu, James Kiarie, and Pascale Allotey, who were not involved in the study, wrote in their commentary: "Fertility rates are a multidisciplinary issue involving multiple stakeholders and disciplines. Scientific forecasts and policy discourse are crucial as we seek answers. Accurate communication will help us better understand the issue and make informed decisions. The decline in total fertility rates poses challenges to global society but also offers opportunities for innovation to help us achieve long-term sustainable development."
Related paper information: https://doi.org/10.1016/S0140-6736(24)00550-6
