Uncertainty about the future as a factor in declining fertility

Anna Louie Sussman, Why So Few Babies? We Might Have Overlooked the Biggest Reason of All. NYTimes, May 7, 2026.

The collective reluctance to procreate is perhaps most glaring in the Nordic countries. With their stable economies, strong social safety nets, robust family policies and equitable gender relations, they maintained relatively high birthrates through the early 2000s. In the aftermath of the financial crisis of 2008, however, sometimes referred to as the Great Recession, births in Norway, Denmark, Sweden and Finland declined, and then declined some more, even as their economies recovered throughout the 2010s. Little about those nations’ family policies had changed, and as far as anyone could tell, men were still doing their share of the dishes. The same downward trend held in the United States, where births have fallen by about 23 percent since 2007, despite high rates of immigration until last year. Births have also been declining in East Asian countries, even though governments in the region have thrown buckets of money at the problem. And in France, despite its longstanding pronatalist policies.

This is not simply a matter of affordability, the buzzword so often invoked to explain why people are choosing to have smaller families. Government support for parents can help, but overall, people are having fewer children both in countries that offer very little and in those renowned for their generous family benefits; moreover, the trend holds among those who are struggling to make ends meet and among those who, like the Riveras, have advanced degrees and salaried jobs. What unites these disparate cultures, policy environments and demographics, researchers are now realizing, is young people’s inescapable and crushing sense that the future is too uncertain for the lifelong commitment of parenthood. Call it the vibes theory of demographic decline.

The future has never been assured, but it feels as though we are living in a time of spectacular uncertainty. In the United States, job tenures have contracted and income volatility has risen. Life expectancy, once on an inexorable march upward, has fallen for less-educated women and men. Many of the forces our economy is built on — A.I., immigration, global trade — feel distressingly volatile; disruption, once a byword for a disturbance or problem, is the governing ethos of a terrifyingly powerful sector of our economy.

There's much more at the link.

Child mortality over the years

Achieving replacement fertility should be quite doable in a world where nearly all children survive to adulthood.

For most of history, our ancestors had to deal with a world where women had to bear four children just to have two that survived, and yet they got the job done. pic.twitter.com/kU03HD6Ubw

— More Births (@MoreBirths) June 6, 2025

If the world's a mess, don't blame Donald Trump

Aaron Benanav, There’s a Reason the World Is a Mess, and It’s Not Trump, NYTimes, April 21, 2025.

The world is a mess.

As President Trump upends global trade through a punitive suite of tariffs and redraws America’s alliances, world leaders are scrambling to respond. They are badly placed to deal with such disruption: Across the world, governments have been losing elections — or barely holding on — in the face of rising discontent. From the United States to Uruguay, Britain to India, an anti-incumbent wave swept through democracies in 2024. But not only democracies are in crisis. China, too, is grappling with social unrest and economic instability. Strife, these days, is global.

There are many explanations for this sorry state of affairs. Some see rapid social change, especially around migration and gender identity, fueling a cultural backlash. Others argue that elites flubbed their pandemic responses or have grown detached from their populations, driving a surge in anti-establishment sentiment and support for strongmen. Another argument holds that algorithm-driven social media has made it easier for misinformation and conspiracy theories to spread, giving rise to greater volatility.

There’s something to each of these theories, to be sure. But there is a deeper force underlying today’s disarray: economic stagnation. The world is experiencing a long-term slowdown in growth rates that began in the 1970s, worsened after the 2008 global financial crisis and shows no sign of improving. Stuck with low growth, waning productivity and an aging work force, the world economy is in a rut. This shared economic predicament lies behind the political and social conflicts the world over.

I agree with this much, we can't blame the sorry state of the world on Donald Trump. He's just a power-mad grifter who's figured out how to exploit the mess for his own gain. And, yes, I believe that the economic stagnation is real. While I'm skeptical of the capitalist mantra of "growth, growth, growth, and more growth," I certainly don't think we've reached a point where a steady-state economy would be better (less strain on the environment). I've been following Tyler Cowen for well over a decade now, perhaps a decade and a half, and he called it in this 2011 book, The Great Stagnation. I note, however, that's he's recently come to believe that we're pulling out of it.

Let's go on with the article, which asks why growth has slowed:

One reason is the global shift from manufacturing to services. This has stalled the primary engine of economic expansion: productivity growth. Productivity — the output per hour worked — can rise quickly in manufacturing. A car factory that installs robotic assembly lines, for example, can double production without hiring more workers, perhaps even firing some. But in services, efficiency is much harder to improve. A restaurant that gets busier usually needs more servers. A hospital treating more patients will require more doctors and nurses. In service-based economies, productivity is always slower to rise.

This seismic shift, in the making for decades, has a name: deindustrialization. In America and Europe, we know what that looks like: lost manufacturing jobs, amid declining demand for industrial goods. But deindustrialization is not limited to wealthy economies. The move from manufacturing to services is happening across the G20, dragging down growth rates nearly everywhere. Today about 50 percent of the world’s work force is employed in the service sector.

There’s another reason for global stagnation: slowing population growth. Birthrates surged after World War II, creating strong demand for housing and infrastructure construction and spurring the postwar boom. Demographers once assumed birthrates would stabilize at replacement level, around two children per family. Instead, fertility rates have tended to fall below this threshold. [...]

This is a big problem for the economy.

Because everything shrinks. What to do? A.I. to "improve efficiency in labor-intensive service sectors like health care and education"? Hasn't worked so far. Reindustrialization, "under strict tariff protections"? That's Trump's gambit.

But here, too, there is cause for doubt. For one thing, the decline in manufacturing was not just about trade. Even manufacturing and export powerhouses like Germany and South Korea have seen industrial employment shrink. For another, the industries generally targeted for revival — semiconductors, electric vehicles and renewable energy — employ relatively few workers. The era when manufacturing could provide mass employment is over.

Benanav doubts that increasing the population is a way out, with which I'm sympathetic. He votes for more deficit spending (two paragraphs) and redistribution.

The second approach is redistribution. In the past, the primary rationale for policies that enriched wealthy households was to stimulate growth from the top down, but this strategy has evidently failed. Instead, governments could place much higher taxes on the rich and redistribute income to the rest of society. That would be an uphill battle in the United States and elsewhere, admittedly, but it would bring big benefits, improving consumer demand and strengthening markets both domestically and internationally.

The goal should be not just to raise income levels, which studies show are increasingly disconnected from happiness, but also to build more stable and equitable societies in a slower-growth world. That requires investing to improve people’s lives: repairing ecosystems, rebuilding infrastructure and expanding housing.

Color me sympathetic, deeply sympathetic. But still, I remain skeptical.

I keep thinking that the world is limping along on social, institutional, and political structures grounded in the 19th century, if not even earlier, and those structures are no longer adequate. Why not? That's a tricky one, and I'm not prepared to answer it. But my thinking is grounded in the cultural ranks theory that David Hays and I developed during the 1990s, and that tells me that we need another restructuring of, of, well, of everything. That's a hard case to argue.

What’s up, or down, with world population?

Chris Armstrong has a post at Crooked Timber with the intriguing title, What if there were far fewer people? (Jan. 8, 2023). The article opens:

One of the most common arguments in debates about environmental crisis is: “it’s the rising population, stupid.” There are just too many human beings, using up too much stuff, leaving too little space for everyone else. The next step is often to gesture towards some kind of population control, or just to leave the issue hanging.

Whatever you think of that position, I’ve been struck lately by the increasing prominence of its diametric opposite. This holds that the problem we face – or will soon face, anyway – is that there are actually too few of us.

It has attracted 89 comments so far. I rather like this one by engels:

The reason Western political classes worry about population isn’t anything long-term but that in the structure of housing markets, careers and welfare systems Western economies are basically Ponzi schemes, that require a continuous stream of enthusiastic twenty-somethings to keep the balls in the air. That be can purveyed either by breeding or immigration, which are (un)popular with different constituencies.

Setting that aside, Armstrong then links to this article: Dean Spears, The World’s Population May Peak in Your Lifetime. What Happens Next? NYTimes, Sept, 2023.

Spears points out that, if current trends in population growth continue, the world’s population is likely to peak at about 10 billion late in this century, around 2085, and then begin to decline. Why would it decline? Because people throughout the world are choosing smaller family sizes.

Any worldwide average of fewer than two children per two adults means our population shrinks and in the long run each new generation is smaller than the one before. If the world’s fertility rate were the same as in the United States today, then the global population would fall from a peak of around 10 billion to less than two billion about 300 years later, over perhaps 10 generations. And if family sizes remained small, we would continue declining.

I must admit, that doesn’t bother me very much. I see no inherent virtue in a large population and am inclined to think that reducing humanity’s drain on world resources would be a good thing. However:

Over the past 200 years, humanity’s population growth has gone hand in hand with profound advances in living standards and health: longer lives, healthier children, better education, shorter workweeks and many more improvements. Our period of progress began recently, bringing the discovery of antibiotics, the invention of electric lightbulbs, video calls with Grandma and the possibility of eradicating Guinea worm disease. In this short period, humanity has been large and growing. Economists who study growth and progress don’t think this is a coincidence. Innovations and discoveries are made by people. In a world with fewer people in it, the loss of so much human potential may threaten humanity’s continued path toward better lives.

That remains to be seen. The most obvious objection is taken up in a more recent post (Jan. 12) at Crooked Timber by John Quiggin, Mute inglorious Miltons. After a brief quote from Gray’s “Elegy Written in a Country Churchyard,” Quiggin notes:

Billions of people alive today (the majority of whom are women) [...] with their potential unrealised through lack of access to education and resources to express themselves. Rather than adding to their numbers, or diverting yet more resources away from them, we ought to be focusing on making a world where everyone has a chance to be a great poet or inventor.

I’m deeply sympathetic to that argument. I would also note that we are moving into a future where new and as yet unimagined or just-barely imagined computational tools (so-called AI) will augment and extend human creativity. For those reasons alone it is not at all obvious to me that we can justify an ever-larger population by pointing out that we need more people to make more “inventions and discoveries.” Frankly, this kind of argument strikes me as a rationalization for the Ponzi scheme economic structure that engels pointed out.

Let us return to Spears:

Sustained below-replacement fertility will mean tens of billions of lives not lived over the next few centuries — many lives that could have been wonderful for the people who would have lived them and by your standards, too.

That strikes me as typical long-termist thinking which, in this instance, I think is bonkers. I do not think that the universe is keeping tabs on how much ‘goodness’ there is in the world and will, at some future date, be raising the ethical action (EA) scores of those who have contributed to a long-term term increase in goodness by encouraging population growth in the present.

Let’s continue with Spears:

Perhaps that loss doesn’t trouble you. It would be tempting to welcome depopulation as a boon to the environment. But the pace of depopulation will be too slow for our most pressing problems. It will not replace the need for urgent action on climate, land use, biodiversity, pollution and other environmental challenges. If the population hits around 10 billion people in the 2080s and then begins to decline, it might still exceed today’s eight billion after 2100. Population decline would come quickly, measured in generations, and yet arrive far too slowly to be more than a sideshow in the effort to save the planet. Work to decarbonize our economies and reform our land use and food systems must accelerate in this decade and the next, not start in the next century.

This isn’t a call to immediately remake our societies and economies in the service of birthrates. It’s a call to start conversations now, so that our response to low birthrates is a decision that is made with the best ideas from all of us. Kicking the can down the road will make choices more difficult for future generations. The economics and politics of a society in which the old outnumber the young will make it even harder to choose policies that support children.

If we wait, the less inclusive, less compassionate, less calm elements within our society and many societies worldwide may someday call depopulation a crisis and exploit it to suit their agendas — of inequality, nationalism, exclusion or control.

By all means, let’s start those conversations.

Why are birthrates low?

The main reason that birthrates are low is simple: People today want smaller families than people did in the past. That’s true in different cultures and economies around the world. It’s what both women and men report in surveys.

Humanity is building a better, freer world with more opportunities for everyone, especially for women. That progress deserves everyone’s greatest celebration — and everyone’s continued efforts. That progress also means that, for many of us, the desire to build a family can clash with other important goals, including having a career, pursuing projects and maintaining relationships. No society has solved this yet. These tradeoffs bite deep for parents everywhere. For some parents, that means struggle. For others, that means smaller families than they hoped for. And for too many, it means both.

Yes, celebrate by all means. And I agree that we do have a problem of conflicting desires. As far as I know Spears is correct that no society has yet solved that problem.

But that problem will exist regardless of how large the world’s population grows. The problem, as described, has to do with allocation of time, effort, and resources at the level of individuals and families. Adopting policies that encourge the increase of population beyond 10 billion will do nothing to alleviate the conflict that individuals and families feel about the allocation of their attention and other resources. On that score, such policies will only increase the number of people who feel this clash of desires. How does one enter that clash into the utilitarian calculus of goodness?

Why the lag between Malthus’ concern about population and science fiction? [Why not ask Chat?]

That’s a question Adam Robert’s posed recently:

The prospect of a hugely over-crowded, hyperpopulated future was one raised, famously, by Malthus in his 1798 book An Essay on the Principle of Population. Throughout the 19th-century, the issue was discussed and debated by scientists, commentators, by the writers of magazine articles and publishers of tracts. There were anti-Malthusians who thought the Essay too pessimistic, and rather more who thought its argument sound and who debated the best way to address or ameliorate its alarming prophesy. But here’s my question: why was there no fictional representation of this topic at this time? Science fiction was a vigorous and varied discourse during the whole century, after all. Why did no writers pick-up on over-population as an imaginative theme?

Apparently it wasn’t until the mid-1960s that science fiction took up the problem of over-population. Roberts goes on to note lots of non-fiction took up the topic.

It’s an interesting question, for which I have no answer. If I were to think about it, I’d probably start by asking what made the topic salient in the mid-1960s, which also saw popularization of the problem in non-fiction, e.g. Paul Ehrlich’s The Population Bomb.

At the suggestion of Tyler Cowen, I put the question to ChatGPT. I used the Roberts paragraph as a prompt. Here’s its response (in that pesky numbered list format):

The absence of fictional representations of over-population in 19th-century science fiction despite the intense discussions on the topic can be attributed to several factors. One possible explanation is the cultural and literary context of the time.

1. Literary Tradition and Focus: The 19th century was marked by different literary traditions, and science fiction as a distinct genre was still evolving. Many writers were influenced by Romanticism, Gothic literature, and adventure narratives. The focus of literary works might not have been aligned with the scientific and demographic concerns of the time.
2. Dominant Themes in Science Fiction: Science fiction of the 19th century often explored themes related to technological advancements, exploration, utopias, and dystopias. Writers were more inclined to envision futuristic societies driven by technological innovation rather than focusing on population-related issues.
3. Social and Political Sensitivities: The 19th century was a time of significant social and political changes, including industrialization and urbanization. Writers may have been hesitant to address the sensitive issue of over-population directly in their fiction due to concerns about societal reaction or censorship.
4. Emerging Nature of Science Fiction: During this period, science fiction as a genre was still finding its voice and expanding beyond traditional speculative narratives. The literary landscape was more inclined towards exploring the unknown, otherworldly, and scientific marvels rather than delving into socio-economic issues.
5. Limited Scientific Understanding: While Malthusian ideas were discussed, the understanding of population dynamics and demographics was not as advanced as it is today. Writers may not have had a comprehensive scientific basis to build fictional narratives around over-population.

It's worth noting that science fiction as a genre evolved over time, and the exploration of over-population as a theme became more prevalent in the 20th century when demographic concerns gained renewed attention.

And then there’s the related question: Science fiction did take up the problem in the 1960s – e.g. Harrison, Make Room! Make Room” (1966), Burgess, That Wanting Seed (1962), Brunner Stand on Zanzibar (1968). Why?

The emergence of over-population as a prominent theme in science fiction during the 1960s can be attributed to several factors, reflecting the cultural, social, and scientific context of that time.

1. Population Growth Concerns: The 1960s witnessed a heightened awareness of global population growth and its potential consequences. Issues such as resource depletion, environmental degradation, and the strain on societal structures became more pronounced. Science fiction writers often draw inspiration from contemporary concerns, and the perceived urgency of addressing over-population likely influenced their choice of themes.
2. Advancements in Demography and Ecology: By the 1960s, there were significant advancements in the understanding of demography, ecology, and environmental science. The scientific community's increasing awareness of the impact of unchecked population growth provided a more solid foundation for writers to explore these themes in a speculative context.
3. Social and Cultural Changes: The 1960s marked a period of social upheaval and cultural change. Issues related to civil rights, environmentalism, and population control were part of the broader social discourse. Science fiction, as a genre, often reflects and engages with contemporary social concerns, making it a suitable platform for exploring over-population as a speculative concept.
4. Literary Trends and Experimentation: The 1960s saw a broader acceptance of experimental and unconventional literary styles. Authors like John Brunner, in "Stand on Zanzibar," used innovative narrative techniques to explore complex themes, including over-population. This period allowed for more daring and thought-provoking approaches to storytelling.
5. Dystopian Turn in Science Fiction: The 1960s marked a shift towards dystopian themes in science fiction. Authors began to explore the dark side of technological and societal progress. Over-population served as a compelling element in dystopian narratives, reflecting fears and anxieties about the future.
6. Influence of Earlier Discussions: The discussions on over-population in the earlier part of the 20th century, including those inspired by Malthus, may have laid the groundwork for writers to revisit and expand on these themes with a more nuanced understanding.

In summary, the 1960s provided a fertile ground for science fiction writers to delve into the topic of over-population due to a convergence of scientific, social, and cultural factors that made the theme both relevant and compelling for speculative exploration.

Not entirely satisfactory, but it does suggest points of attack, if that’s the right word.

Youth Quake Africa: By 2050 one person in four will be African [Kisangani 2150]

Declan Walsh, The World Is Becoming More African, NYTimes, Oct. 28, 2023.

Opening paragraphs:

Astonishing change is underway in Africa, where the population is projected to nearly double to 2.5 billion over the next quarter-century — an era that will not only transform many African countries, experts say, but also radically reshape their relationship with the rest of the world.

Birthrates are tumbling in richer nations, creating anxiety about how to care for, and pay for, their aging societies. But Africa’s baby boom continues apace, fueling the youngest, fastest growing population on earth.

In 1950, Africans made up 8 percent of the world’s people. A century later, they will account for one-quarter of humanity, and at least one-third of all young people aged 15 to 24, according to United Nations forecasts.

The median age on the African continent is 19. In India, the world’s most populous country, it is 28. In China and the United States, it is 38.

The implications of this “youthquake,” as some call it, are immense yet uncertain, and likely to vary greatly across Africa, a continent of myriad cultures and some 54 countries that covers an area larger than China, Europe, India and the United States combined. But its first signs are already here.

It reverberates in the bustle and thrum of the continent’s ballooning cities, their hectic streets jammed with new arrivals, that make Africa the most rapidly urbanizing continent on earth.

It pulses in the packed stadiums of London or New York, where African musicians are storming the world of pop, and in the heaving megachurches of West Africa, where the future of Christianity is being shaped.

And it shows in the glow of Africa’s 670 million cellphones, one for every second person on the continent — the dominant internet device used to move money, launch revolutions, stoke frustrations and feed dreams.

“It feels like the opportunities are unlimited for us right now,” said Jean-Patrick Niambé, a 24-year-old hip-hop artist from Ivory Coast who uses the stage name Dofy, as he rode in a taxi to a concert in the capital, Abidjan, this year.

Afrobeats:

When the Nigerian star Burna Boy stepped out before an adoring crowd at New York’s Citi Field this summer, he confirmed himself as pop royalty.

Weeks earlier, in London, he had filled an 80,000-capacity venue. In New York, he became the first African artist to sell out an American stadium.

He sang his new single, “Sittin’ on Top of the World.”

It was yet another milestone for Afrobeats, a West African musical genre that is becoming a global sensation. Afrobeats songs were streamed over 13 billion times on Spotify last year, up from eight billion in 2021; the genre’s biggest hit, Rema’s “Calm Down,” was a fan phenomenon at the soccer World Cup in Qatar. Countless TikTok dance challenges were born.

“It’s a great time to be alive,” said Laolu Senbanjo, a Nigerian artist living in Brooklyn. “Whether I’m in Target or an Uber, I hear the Afrobeats. It’s like a bridge. The world has come together.”

African artists seemed to be on red carpets everywhere this year — at the Grammy Awards, which added a new category for Best African Music; at the Met Gala, where the Nigerian singer Tems came fringed in ostrich feathers; and at the Cannes Film Festival, where a young French-Senegalese director, Ramata-Toulaye Sy, was a breakout star.

There's much more at the link.

When will the earth's population peak, and what happens then?

Dean Spears, The World’s Population May Peak in Your Lifetime. What Happens Next?, NYTimes.

Most people now live in countries where two or fewer children are born for every two adults. If all people in the United States today lived through their reproductive years and had babies at an average pace, then it would add up to about 1.66 births per woman. In Europe, that number is 1.5; in East Asia, 1.2; in Latin America, 1.9. Any worldwide average of fewer than two children per two adults means our population shrinks and in the long run each new generation is smaller than the one before. If the world’s fertility rate were the same as in the United States today, then the global population would fall from a peak of around 10 billion to less than two billion about 300 years later, over perhaps 10 generations. And if family sizes remained small, we would continue declining.

What would happen as a consequence?

Next:

Sustained below-replacement fertility will mean tens of billions of lives not lived over the next few centuries — many lives that could have been wonderful for the people who would have lived them and by your standards, too.

Perhaps that loss doesn’t trouble you. It would be tempting to welcome depopulation as a boon to the environment. But the pace of depopulation will be too slow for our most pressing problems. It will not replace the need for urgent action on climate, land use, biodiversity, pollution and other environmental challenges. If the population hits around 10 billion people in the 2080s and then begins to decline, it might still exceed today’s eight billion after 2100. Population decline would come quickly, measured in generations, and yet arrive far too slowly to be more than a sideshow in the effort to save the planet. Work to decarbonize our economies and reform our land use and food systems must accelerate in this decade and the next, not start in the next century.

This isn’t a call to immediately remake our societies and economies in the service of birthrates. It’s a call to start conversations now, so that our response to low birthrates is a decision that is made with the best ideas from all of us.

Long-run population decline?

n fact, in none of the countries where lifelong fertility rates have fallen well below two have they ever returned above it. Depopulation could continue, generation after generation, as long as people look around and decide that small families work best for them, some having no children, some having three or four and many having one or two.

Nor can humanity count on any one region or subgroup to buoy us all over the long run. Birthrates are falling in sub-Saharan Africa, the region with the current highest average rates, as education and economic opportunities continue to improve. Israel is an example of a rich country that, as of today, has above-replacement fertility rates. But there, too, fertility rates have been falling over the decades, from 4.5 in 1950 to 3.0 today. Israel may not be above 2.1 for many more generations.

Living in a "smaller" world ((much)lower population)?

There are many ways to live a life or be a family, and having that freedom and diversity is good. If an inclusive, compassionate response to population decline emerges someday, it need not be in conflict with those values. If one in every four pairs of American adults would choose to have one more child, that would be enough to stabilize the U.S. population. In that future, there would still be many ways to live a life or be a family; two kids on average doesn’t mean two kids for everyone.

Nobody yet knows what to do about global depopulation. But it wasn’t long ago that nobody knew what to do about climate change. These shared challenges have much in common, which gives humanity some shared experience to build on.

There's much more at the link.

China's population is less than 1.28 B, not the official 1.41 B [India is No. 1!]

Recently leaked China's population data confirm my estimates: births began to decline in 1991, with no peak in 2004 or 2011; Population is now less than 1.28 billion, not the official 1.41 billion; Population began to shrink in 2018, not 2031 as officially predicted. pic.twitter.com/xCge7cTRFS

— 易富贤YI Fuxian《大国空巢》 (@fuxianyi) July 9, 2022

Based on this demographics alone China will collapse as a country this decade and that is assuming literally nothing else goes wrong with their energy or food imports or the extreme cult of personality that Xi has set up. Most likely a complete decivilization is going to happen

— Evan Oliai (@evbot_exe) July 9, 2022

Tbh No one is know how many ppl live in India even govt

— Gon70 (@realGon70) July 9, 2022

<p>H/t Tyler Cowen </p>

Population growth is slowing down

Damien Cave, Emma Bubola, Choe Sang-Hun, Long Slide Looms for World Population, With Sweeping Ramifications, NYTimes, May 22, 2021.

All over the world, countries are confronting population stagnation and a fertility bust, a dizzying reversal unmatched in recorded history that will make first-birthday parties a rarer sight than funerals, and empty homes a common eyesore.

Maternity wards are already shutting down in Italy. Ghost cities are appearing in northeastern China. Universities in South Korea can’t find enough students, and in Germany, hundreds of thousands of properties have been razed, with the land turned into parks.

Like an avalanche, the demographic forces — pushing toward more deaths than births — seem to be expanding and accelerating. Though some countries continue to see their populations grow, especially in Africa, fertility rates are falling nearly everywhere else. Demographers now predict that by the latter half of the century or possibly earlier, the global population will enter a sustained decline for the first time.

A planet with fewer people could ease pressure on resources, slow the destructive impact of climate change and reduce household burdens for women. But the census announcements this month from China and the United States, which showed the slowest rates of population growth in decades for both countries, also point to hard-to-fathom adjustments.

The strain of longer lives and low fertility, leading to fewer workers and more retirees, threatens to upend how societies are organized — around the notion that a surplus of young people will drive economies and help pay for the old. It may also require a reconceptualization of family and nation. Imagine entire regions where everyone is 70 or older. Imagine governments laying out huge bonuses for immigrants and mothers with lots of children. Imagine a gig economy filled with grandparents and Super Bowl ads promoting procreation.