PRB

My children were born in 2012 and 2014, and it’s nearly certain they’ll be alive to see the world’s population peak. The probability of peak population this century now sits at 80%—up from 30% just a decade ago, according to the World Population Prospects 2024 released today by the United Nations. My sons’ reality is different from the one I grew up in, where the prevailing fear was not that the number of humans would peak, but that it would grow out of control.

The news from the UN tracks with the tenor of most headlines about population trends—”Everyone’s getting old! No one’s having babies!”—and it’s a jarring shift from the population dynamics that first intrigued me to go into the population field as a young environmentalist. But while my own career (and the headlines) eventually shifted more in the direction of population aging and shrinking, we shouldn’t get so caught up in these trends that we forget about the countries at the other end of the demographic transition—the ones that attracted many of us to study population in the first place.

We desperately need to understand what it means politically, socially, and economically for the demographic basis of France, Mexico, and the United States to shift so dramatically to older populations, but we can’t do so to the exclusion of countries at the other end of the demographic transition, like Kenya, Nigeria, and Pakistan. We must hold two things to be true: Populations are rapidly shrinking and rapidly booming—just in different places.

Sure, if we have to boil it down to one defining global trend, it’s toward lower fertility rates. At the global level, the average number of live births per woman is now below 2.3, sitting just a pinch above what demographers call “replacement level.” According to the new UN data, over half of all countries have below-replacement fertility, and nearly 1 in 5 have ultra-low fertility (below 1.4 births per woman).^[1]. Yet, at the same time, about 1 in 10 countries has a fertility rate above 4 births per woman. That so few countries still have high fertility rates is evidence of a large-scale demographic shift toward smaller family sizes and older populations.

But even as we rightly scramble to navigate these seismic shifts, we must keep our agenda focused on the political, health, and economic issues faced by countries on the other side of the demographic divide.

Some of the countries experiencing the most instability and hardship today will see their populations double over the next 30 years, including Angola, the Democratic Republic of the Congo, Niger, and Somalia. While sub-Saharan Africa is not the only place in the world with high-fertility countries, it does have the highest fertility rate of all major regions.

Middle Africa’s fertility rate of 5.5 births per woman is higher than the continent’s average; only 22% of married women there use any sort of contraception and only 29% of their demand for modern contraception is met, according to the latest data from PRB. Western Africa, with a fertility rate of 4.4, is home to five partner countries in the U.S. Strategy to Prevent Conflict and Promote Stability: Benin, Côte d’Ivoire, Ghana, Guinea, and Togo. But the youthful age structures of these nations compound the challenges around achieving stability and prosperity. (In Benin, for example, 42% of the population is under age 15.)

Smaller families are a byproduct of investments in education and rights-based family planning, which themselves yield broad societal benefits.

And there’s a positive feedback loop: when women have fewer children—say, three instead of six—they have fewer barriers to engaging in paid work outside the home, which benefits the entire family. When women wait to have kids until after they’ve completed their education, it opens up opportunities for them to earn more money throughout their lives—a benefit to both their individual financial security and that of their future families. Having kids at a very young age, however, can be physically dangerous for both mothers and babies and makes furthering education or engaging in paid work incredibly difficult, closing doors to better individual and family well-being in the long run. Despite advances in many places to decrease teen pregnancy, in 2024, 3.5% of all births will be to mothers under age 18—340,000 of those to girls under age 15, according to the UN.

There’s a demographic divide in terms of health, as well. In Western Africa, life expectancy at birth is only 58 years, while it tops 82 years in Western and Southern Europe. Investments in primary health care can particularly benefit lower- and middle-income countries whose populations are aging rapidly and who will need to find cost-effective ways to meet the needs of more older people.

Developing a more adaptable primary health care system to handle both currently young but rapidly increasing older populations—something countries like India (fertility rate of 2.0) and Indonesia (fertility rate of 2.1) will have to do—can pave the way for healthier, more resilient societies.

So, what do we do now? Is the demographic divide a cause for despair? The upside is that there are tried-and-true interventions to improve people’s well-being on either side of the divide. In young and rapidly growing countries, these interventions include ending child marriage, providing access to family planning, investing in education, and shoring up primary health care systems. In aging and shrinking (or slow-growing) countries, these measures include investing in health and care infrastructure to meet a rapidly rising demand for elder care and a continued need for child care—responsibilities that most often fall on women. Yet, even countries with low fertility have a need to ensure continued access to contraception and attention to reproductive health.

To make sure tomorrow looks brighter, we have to work for the well-being of everyone. We can’t let any one side of the demographic divide dominate the headlines—or our policy agendas.