News that the number of living humans had passed eight billion in November 02022 sparked predictable arguments between people inclined to celebrate this milestone and those who worry about the planet’s carrying capacity.
Amid the torrent of commentary, Long Now cofounder Stewart Brand posted a characteristically contrarian tweet:
“The ‘drop dramatically’ I still expect. But it won’t be from my predicted 8 billion.”
Brand was referring to a Long Bet he made 14 years ago, in 02009:
“Human population of the world will peak at or below 8 billion in the 02040s and then drop dramatically.”
The bet was based on the fact that fertility rates all over the world have been decreasing steadily for 60 years. Even as the total human population continues to rise, fertility in most countries has dipped below the “replacement rate” of 2.1 children per woman, and the downward trend is accelerating. Brand overestimated the speed of this transition, but he is sticking with the view held by many demographers that the human tide will start to ebb in the second half of this century.
Although most people are aware of declining birthrates, the idea of outright depopulation remains “fantastically counter-intuitive,” says Phillip Longman, author of The Empty Cradle: How Falling Birthrates Threaten World Prosperity and What to Do About It (02004). We can easily conceptualize the temporary population losses caused by war, famine, disasters, or disease, partly because we know that our species has always surged back after these setbacks. But the notion that humanity might voluntarily pause, pivot, and retreat — by having fewer children — seems implausible, if not absurd. When the New York Times publishes a feature on the effects of falling birthrates, for example, readers respond with a mix of skepticism and outrage. Their comments could be summarized as shouting “In an age of rapacious consumption, collapsing ecosystems and massive emigration, do you really expect us to believe that fewer people are a problem?”
The overpopulation story is old, visceral and hard to refute. Each day brings fresh signs of our heavy footprint on a visibly crowded planet. Fretting about the eventual reversal of this phenomenon, WIRED magazine recently declared, “is like someone in the year 1000 worrying about the Y2K bug.”
Is it really too early to contemplate this possibility? Nineteen years ago, the Long Now Foundation invited Longman to give a presentation about his book. At the time, Longman was a fellow at the New America Foundation, a left-of-center think tank in Washington, where he was researching the impact of aging on entitlement programs. When he and his late wife were unable to conceive a child, Longman began to study fertility trends. The Empty Cradle, the result of that study, synthesized decades of research showing that in many rich countries, fertility rates were so low that they threatened to create a self-reinforcing cycle of depopulation that would be extremely difficult to reverse. He cited the work of numerous demographers and economists who warned that such a cycle could be profoundly destabilizing.
In a recent interview, Longman said that the book received a chilly reception from progressive organizations and media outlets, who saw it as a veiled attack on gender equality, reproductive rights, and the sustainability goals of Paul R. Ehrlich (author of The Population Bomb) and other environmentalists.
Reactions from conservatives were somewhat warmer. Longman was invited to speak by Focus on the Family and other religious organizations, as well as by governments in Russia, Japan and Poland that wanted his advice on increasing birthrates. But when parts of his book began to be selectively cited by people with nationalist and far-right agendas, Longman decided to step away and move on to other research topics.
In the years since The Empty Cradle was published, the discussion around demographic decline has become ever more fraught. Pope Francis laments that “selfish” people prefer dogs and cats to having children, provoking a furious backlash from pet lovers. Elon Musk warns that depopulation threatens civilization, to which WIRED shoots back: “Elon Musk Is Totally Wrong About Population Collapse.” Forbes magazine broods over the economic impact of “Death Spiral Demographics,” while broadcaster David Attenborough uses his nature documentaries to argue that biodiversity can only be preserved if humans stop multiplying.
Amid this cacophony, the demographer Lyman Stone recently observed that demographic decline has become “too broad even to discuss: it means too many old people, too many brown people, too many disabled people, or not enough people […] it is all things to all people, a stick with which to beat today’s bogeyman.”
Nevertheless, it should be possible to determine the extent to which depopulation is actually taking place—and to see whether Longman’s warning was prescient or misguided. A close reading of the 02022 report published by the United Nations Population Division, whose forecasts are widely cited by demographers, offers a useful starting point.
An invisible decline
When the United Nations first began issuing periodic population forecasts in 01950, sub-replacement fertility — the necessary prelude to depopulation — was extremely rare. In the 01970s and 01980s, a handful of industrialized countries dropped below that threshold, and soon countries in Asia and Latin America began to join their ranks. Today, the United Nations data show that seven out of ten people live in countries with sub-replacement birth rates. (See graphs, “Which countries are depopulating?”)
Above-replacement fertility is now largely limited to the world’s poorest and least developed countries. Population growth in this group, which totals around 2.2 billion people, is expected to continue for a long time. In fact, the United Nations estimates that nearly all the population growth forecast for the rest of this century will take place in these countries. However, fertility levels in this group are similar to what they were in Latin America and Asia just one or two generations ago, and they could drop just as quickly as they did in those regions.
On the sub-replacement side, countries can be further divided into three categories. The first consists of countries that are still registering what demographers call momentum-driven growth. Some 2.8 billion people live in this group, which includes India, Bangladesh, Brazil, Mexico, Iran, Vietnam, Turkey and Malaysia.
Like a locomotive that suddenly runs out of fuel while steaming uphill, population in these countries will keep climbing for a short time thanks to the “momentum” provided by girls and young women who have yet to enter their reproductive years. But as those women reach middle age, the locomotive will stop, start rolling backwards, and then gain reverse momentum. The United Nations forecasts that Brazil’s population will shrink by 45 million people by the end of the century. Bangladesh could end up with 30 million people fewer than at its peak. Even India, which will keep growing till around 02060 because of its enormous cohorts of young people, is on track to lose at least 200 million people between 02070 and 02100.
The second sub-replacement category is made up of around 800 million people in countries that rely on immigrants to supplement natural growth rates that are already negative (Germany, Spain) or barely above zero (Canada and the United States). Assuming they continue to take in immigrants in large numbers, the United Nations forecasts that these countries will either shrink slightly (France) or grow anemically (the United Kingdom) between now and 02100.
The third category consists of countries that are already depopulating. When Longman published his book, this group was still tiny. Actual depopulation — where deaths consistently outnumber births — was concentrated in Russia and Eastern European countries that together accounted for less than 4 percent of the global population. But in the years since then Japan, Italy, South Korea, Taiwan, Greece and Portugal, among others, have joined this category. The government in China recently acknowledged that it began to depopulate in 02022.
This means that in all, more than 2.1 billion people — a quarter of humanity — now live in countries that are smaller each evening than they were in the morning. Because it is diffused throughout millions of people, this phenomenon is essentially invisible to the public, but the numbers are startling in aggregate. Each month, Russia’s population diminishes by around 86,000 people (not including casualties from the war in Ukraine), Japan’s by around 50,000, and Italy’s by at least 20,000. Fertility in these countries has been so low for so long that depopulation is cemented into their future, regardless of any near-term recovery in birthrates. Overall, the UN anticipates that their populations will shrink by between 20 percent and 50 percent by the end of the century. Other studies anticipate much larger and faster declines.
Where’s the floor?
In short, the United Nations data show that Longman’s predictions were entirely correct. Twenty years ago, depopulation or immigration-dependency were demographic oddities; today, they are the norm for virtually all wealthy and technologically advanced nations. Within a single generation (by around 02050), they will be a feature of most of the world’s societies, as unremarkable as universal literacy or high obesity levels are today.
The forces that have brought us to this point — economic development, urbanization, access to education and contraception, changing gender roles — are not likely to be reversed. None of the countries whose fertility has dropped below replacement levels has subsequently returned to sustained growth. As Joseph Chamie, a former director of the United Nations Population Division, recently put it: “Once a nation’s fertility rate falls below the replacement level, it tends to stay there.” The question is no longer whether most countries will depopulate, but at what pace they will do so.
Longman was also right about many of the downsides of this phenomenon. Companies in mature economies are indeed struggling to find employees amid the shrinking number of working-age people. Pension systems are buckling under the weight of longer life expectancies and worsening ratios of contributors to beneficiaries. Xenophobia has risen in many of the wealthy, aging countries that are most dependent on immigration. South Korea has been forced to close nearly 4000 schools for lack of students. Universities in the US, where the number of college students has been falling since 02010, are bracing for an “enrollment cliff” starting in 02025. And in Europe, the “one euro house” phenomenon has become a cliché for the extreme tactics needed to prevent the proliferation of rural ghost towns.
If this sounds like old news — and not quite a catastrophe — it is because expectations and behaviors have been quietly shifting to accommodate the reality of depopulation. Indeed, The Empty Cradle (like Fewer, The Coming Population Crash, Empty Planet, and other books in this category) can all be faulted for underestimating how quickly humanity will adapt to this predicament — just as we have adapted to countless other slow-moving challenges. Japan, which began to depopulate around 02010, is a case in point. After three decades of fruitless efforts to boost birth rates, it has embarked on a more pragmatic policy of “aging gracefully.” Although its economic growth has been lackluster since the 01990s, Japan has continued to improve overall quality of life for its citizens, while achieving unemployment and inequality indicators superior to those of many European countries.
Yet even as these adaptations take place, public discourse around depopulation is firmly anchored in the previous century. On the Right, depopulation is still reflexively described as an aberration, a symptom of moral decay, or a signal of impending economic doom. On the Left, it is too often dismissed as a non-issue or welcomed as a step toward degrowth – one whose environmental benefits will surely outweigh any social costs. Policymakers and academics tend to avoid the topic, wary of its proximity to the agendas of authoritarian regimes and culture war battlegrounds around abortion or immigration.
That is unfortunate, because the era of depopulation poses new dilemmas that require fresh thinking and open debate. Twenty years ago, for example, many demographers still believed that the very low fertility rates then prevalent in Europe were a temporary phenomenon, and that fertility would eventually bounce back and converge close to two children per woman. The assumption was that growing gender equality and rising standards of living would make it easier for women in developed countries to reconcile their career goals with their stated desire to have children. Although a few rich countries subsequently achieved modest fertility gains, most of those increases have evaporated in the last ten years. Fertility is plummeting in places as varied as Jamaica, Uruguay, South Africa, Iran and the United States. And in China and South Korea, it has dropped to levels that were previously considered impossible for large countries.
These trends have given new urgency to the question of just how far fertility can descend before it imposes unmanageable strains on a society. Wolfgang Lutz, an Austrian demographer and founder of the Wittgenstein Centre for Demography and Global Human Capital, is one of a small number of academics who have openly grappled with this issue. Lutz acknowledges that “nobody knows” whether fertility rates will recover or continue to fall, because demography lacks a theoretical framework for determining whether a fertility “floor” exists. In the absence of a testable hypothesis, demographers have relied on surveys that ask people to state their ideal family size. For decades, these surveys provided a reassuringly consistent benchmark: across almost all cultures and income levels, large majorities of women reported two or more children as their ideal.
Now, that benchmark has also begun to slide. In some countries, studies show that the number of children that women actually intend to have is lower than their stated ideal family size. In others, social norms appear to be shifting towards a new ideal that is far below two children. Tomas Sobotka, a colleague of Lutz’s at the Wittgenstein Center, says that South Korea offers the most striking example of this trend. “A combination of rapid economic development, very high levels of education among young adults, very competitive labor market, long work hours, unaffordable housing, traditional gender norms and persistent gender inequalities in work and family life have created a perfect storm — conditions that make it very difficult for young people to marry and pursue their fertility plans,” Sobotka said via email. “The question is what happens if young Koreans get accustomed to living single and childfree lives. The research I have been conducting with my colleagues shows that the appeal of marriage and having children has been vanishing among the young adults and many of them are likely to stay unmarried, childfree and without a partner.”
Maria Rita Testa, a professor of demography at Luiss University in Rome, sees a similar pattern in Italian society. In a forthcoming paper, she and two colleagues find that projections of Italy’s future population continue to assume that fertility rates will return to levels substantially higher than they are today. Given that fertility in Italy has stayed between 1.2 and 1.4 children per woman for the last 40 years, “it is anything but obvious that fertility will recover in Italy,” Testa wrote in response to questions about her paper. After such a long period, what were once unusual reproductive behaviors have come to be perceived as normal, and she sees no reason to believe that this will change in the near future.
Escaping the low fertility trap
The consequences of these shifting norms could be enormous, because tiny differences in sub-replacement fertility rates have outsize effects on the pace of depopulation. To illustrate this, Sobotka offers four scenarios for anticipating the number of children that could be born in the future of a hypothetical country where there is no immigration. At a fertility rate of 1.85, the process is so gradual that it can take more than two centuries for the number of newborns to shrink by half. But at lower fertility rates, depopulation accelerates because of reverse momentum. At a fertility rate of 1.6, it takes around 90 years for the number of newborns to drop by half. At 1.3, it takes some 50 years. And at a fertility rate of one child per woman — a level already common in many parts of Asia — it can take less than 30 years: each generation has half as many children as the previous one.
Lutz anticipated this risk in a widely cited 02007 paper where he posited a “Low Fertility Trap Hypothesis.” He challenged fellow researchers to consider whether the combination of demographic, cultural and economic forces that had already driven fertility down in Europe were becoming self-reinforcing and irreversible. In the years since then, social scientists have not offered a plausible alternative to this hypothesis. In fact, the whole question of how depopulating countries can hope to end or at least slow down this process seems oddly under-investigated, given what is at stake. One of the few recent books to directly engage the issue is Decline and Prosper! Changing Global Birth Rates and the Advantages of Fewer Children by Norwegian population economist Vegard Skirbekk. He argues that by adjusting pension systems, health services and infrastructure to suit the needs of aging communities, depopulating countries can continue to thrive. It is a refreshing alternative to the apocalyptic drumbeat surrounding this topic, but it does not offer a way out of the low-fertility trap.
In the political sphere, depopulation remains perennially stuck beyond the pertinent time horizon, because even promising actions (such as a new subsidy for first-time parents) take least a quarter century to pay dividends (the time between the birth of a child and her emergence as a tax-paying worker and potential parent). The rare policymaker who does take up this banner soon learns that evidence on the effectiveness of pronatalist policies is sparse — and sobering. Russia has used lavish “cash-for-babies” programs and housing subsidies to achieve modest upticks in fertility, but these have been ephemeral. South Korea, which has spent $200 billion in the last 16 years on programs to encourage childbirth, now has the world's lowest fertility rate. Most experts agree that instead of trying to boost birth rates, governments should stick to the fundamental work of improving overall well-being.
Leaders in depopulating countries have also noticed that the general public is not clamoring for action. A casual review of news headlines from South Korea and Italy shows that people there, like their counterparts everywhere, are focused on immediate headaches such as inflation, housing costs or employment. Few things are more tangible than the anguish of an individual who is thwarted in their efforts to become a parent or form a family. But large-scale depopulation remains a sort of creeping abstraction, too vague and too gradual to engage our jittery attention spans. In fact, it may fall into what some ecologists have called the “invisible present,” a space where we fail to detect slow changes in our surroundings and are unable to interpret effects that lag years behind their causes.
If research and policy won’t bridge the strange void surrounding this topic, perhaps artists and comedians will. With his caustic riff on three reasons not to have kids, Ricky Gervais legitimizes the queasy ambivalence felt by many potential parents. In “What Tsunami?”, Hallie Cantor satirizes the arguments that grandmothers-in-waiting use to badger their daughters. And in innumerable ways, contemporary television series remind audiences of the trade-offs and stresses that make parenting so complicated.
But few writers have attempted to fully flesh out the world that depopulation will bequeath us. In an essay entitled “Why Are There So Few SFF Books About the Very Real Issue of Population Decline?,” the critic James Davis Nicoll points out that science fiction writers are traditionally eager to play with wildly speculative ideas:
“Just not this idea. I can easily name more books that delve into the implications of wormholes, which probably do not exist, and faster-than-light travel, which most definitely does not, than I can books dealing with the demographic transition, whose effects are all around us […] One would think that such a process (enormous, world-wide, moving like a glacier, slow but unstoppable) should make for enthralling fiction. For the most part, however, it hasn’t.”
The one notable exception to this rule, Margaret Atwood’s The Handmaid’s Tale, devotes a single sentence to explaining the demographic origins of its dystopia:
“There was no one cause, says Aunt Lydia… [pointing to] a graph, showing the birth rate per thousand, for years and years: a slippery slope, down past the zero line of replacement, and down and down.”
It is left to us, the readers, to imagine the intricate web of private choices and external forces that could gradually produce the society that Atwood brings memorably to life. And it is also up to us to start telling an alternative story, to fill it with persuasive characters, to imbue them with credible motives, and to plot their journey towards a different ending.
A correction was made on March 9, 02023: An earlier version of this article misspelled the name of a cited critic. He is James Davis Nicoll, not Nichol.
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