When I was first worrying about public policy issues, back in the late 1970s, discussions of fertility rates often invoked the 1968 best-seller, The Population Bomb, written by Paul Ehrlich. At that time, the global population was about 3.5 billion–roughly half its current level. But the book warned that it was already too late, that population was on the brink of overwhelming food supply and the environment, and that there would be mass famine around the globe in the 1970s. Even by the late 1970s, it was clear that the more apocalyptic predictions of the book were hyperbolic. But there was a multi-year famine in the early 1970s in the Sahel region of Africa (basically, a band across the continent reaching from parts of Senegal and Mauritania in the west to Sudan and Eritrea in the east).
I run into a fair number of people who seem to believe that the forecasts of the Population Bomb were only premature, not incorrect. My own sense is that when you predict impending overpoplation leading to mass famine, but then it doesn’t arrive in the next half-century even as population doubles, the odds are good that your analysis has overlooked some key ingredients. The current global food problem involves issues of both too little and too much: that is, about 9% of the world population is undernourished, but 40% of the world population (many of them in lw-income countries) are obese.
Moreover, the current concern seems not to be focused on overpopulation, but on the consequences of low fertility. The June 2025 issue of Finance & Development, published by the IMF, has several articles of interest about declining fertility rates.
In 1950, the global total fertility rate was 5, meaning that the average woman in the world would have five children during her childbearing years, according to the United Nations Population Division. That was well above the 2.1 benchmark for long-term global population stability. Together with low and falling mortality, this drove global population to more than double over a half century, from 2.5 billion people in 1950 to 6.2 billion in 2000. A quarter of a century later, the world’s fertility rate stands at 2.24 and is projected to drop below 2.1 around 2050 (see Chart 1). This signals an eventual contraction of the world’s population, which the UN agency expects to top out at 10.3 billion in 2084. … Over the coming quarter century, 38 nations of more than 1 million people each will probably experience population declines, up from 21 in the past 25 years. Population loss in the coming quarter century will be largest in China with a drop of 155.8 million, Japan with 18 million, Russia with 7.9 million, Italy with 7.3 million, Ukraine with 7 million, and South Korea with 6.5 million …
For those concerned about overpopulation, this news must be concerning in the short run (global population will rise for the next few decades), but perhaps reassuring about the longer run (global population eventually set to decline.
Economists, of course, are proverbial for their every-rose-has-its-thorns mindset–that is, seeing the potential downside in all news. In that spirit, there are obvious concerns over lower fertility. For government finances, a much larger proportion of citizens will be elderly, thus relying on government pension and and health insurance benefits. Economic growth may slow down as well, with a greater share of the population either retired from working and/or starting new businesses.
There is occasional discussion of public policies to encourage families to have more children, but at least so far, countries that have adopted such policies have barely moved the needle of the overall fertility trends. My own sense is that the biggest pro-family policies include affordable family-style housing, high-quality schools and affordable higher-education, and a broader sense that of progress and economic growth.
Other articles in the same issue focus on a different adjustment: can people live longer in a healthy way, and perhaps also plan to work longer before retirement?
Andrew Scott and Peter Piot discuss “The Longevity Dividend,” by which they mean the ability of the healthy elderly to work more years. As they write: “The current health system is at risk of keeping us alive but not healthier for longer, at an ever-increasing cost to individuals, families, and society. In short, in the 20th century, we added years to life. In the 21st, we must add life to these extra years. This requires a shift toward chronic disease prevention and health maintenance, not just treating people when they become ill.”
They describe a social and policy focus on what it would mean to have a society where the expectation for many people was that they would be in good health into their 80s. From an employment view, they add: “But good health alone is not enough to keep people engaged in employment for longer. We also need the kinds of age-friendly jobs older people prefer—with more flexible hours, fewer physical demands, and greater autonomy. By reducing the competition between younger and older workers, such jobs limit the career impact on the former.”
Similarly, Bertrand Gruss and Diaa Noreldin describe “Sustaining Growth in an Aging World.” They point out that people are remaining healthy later into life:
Data on individuals from 41 advanced and emerging market economies reveal that the recent cohorts of older people—those 50 and older—have better physical and cognitive capacities than earlier cohorts of the same age. When it comes to cognitive capacities, the 70s are indeed the new 50s: A person who was 70 in 2022 had the same cognitive health score as a 53-year-old in 2000. Older workers’ physical health—such as grip strength and lung capacity—has also improved. Better health means better labor market outcomes. Over a decade, the cumulative improvement in cognitive capacities experienced by someone aged 50 or over is associated with an increase of about 20 percentage points in the likelihood of remaining in the labor force. It’s also associated with an additional six hours worked per week and a 30 percent increase in earnings. All this could mitigate aging’s drag on growth.
It feels to me as if many people haven’t yet internalized what it means to have a reasonable expectation of living not only longer, but also healthier. I hear from (and about) people who just see it as a chance for a longer and more active retirement. But at least some older people could be enticed by more flexible labor market arrangements to keep a foot (or even just few toes) in the labor market for longer. I suspect that both they as individuals and society as a whole would benefit from that happening.
