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The slow apocalypse: When will we run out of kids?

Rohit Krishnan reframes the global demographic crisis not as a sudden collapse, but as a slow-burning economic inversion where the very lifeblood of growth—working-age people—is drying up. While most headlines focus on immediate inflation or geopolitical tensions, Krishnan forces a confrontation with a quieter, more structural reality: the world is running out of young workers, and the economic machinery built on their labor is beginning to sputter. This is not a story about ideology, but about the hard mathematics of a population pyramid turning upside down.

The Economics of a Shrinking Workforce

Krishnan opens by dismantling the assumption that population decline is a distant, abstract threat. He notes that "almost everywhere in the world, pretty much without exception, has lower birth rates than they used to," with the Total Fertility Rate (TFR) dropping below the replacement level of 2.1 across the developed world and rapidly declining even in emerging economies. The author argues that this is not merely a social shift but a direct threat to aggregate GDP, warning that the International Monetary Fund projects a "1% hit to the global GDP growth annually" as the demographic dividend of the last forty years turns into a drag.

The slow apocalypse: When will we run out of kids?

The piece effectively connects these demographic shifts to tangible financial consequences. Krishnan points out that "with fewer workers and more retirees we will see savings decumulate, because retirees spend more and save less," a dynamic that will inevitably pressure interest rates and pension systems. He highlights the stark reality that in the OECD, the worker-to-retiree ratio is set to double by 2050, necessitating a "5% fiscal tightening or debt" that few political systems are currently prepared to absorb. This analysis is crucial because it moves the conversation from "doom and gloom" to specific fiscal constraints that will define the next half-century.

"Just like the 1980-2020 saw a demographic dividend, the 2020-2050 will see a demographic drag."

Critics might argue that automation and artificial intelligence could offset the labor shortage, rendering the demographic decline less catastrophic. Krishnan acknowledges this, noting that we will need "enough automation to push the labour productivity up enough to make up for labour shortage," but he remains skeptical that technology alone can fully compensate for the loss of human capital and the slowing pace of idea generation.

The Four Pillars of Reversal

Moving beyond diagnosis, Krishnan tackles the difficult question of why fertility rates have fallen so stubbornly and what it would take to reverse the trend. He challenges the common narrative that simply blaming the "cost of living" is sufficient, citing research that suggests the decline is "less a reflection of specific economic costs or policies, but rather, a widespread re-prioritization of the role of parenthood in people's adult lives." This distinction is vital; it suggests that cash handouts alone will fail if the cultural and structural environment remains hostile to family formation.

The author outlines four specific conditions required to return to a stable population: a collapse in the cost of raising children, a decoupling of work and family, a cultural shift in status, and advancements in biotechnology. He is blunt about the limitations of current policy, noting that nations like Hungary and Korea that "burn 3-6% of GDP on baby bonuses" have seen only temporary bumps, with fertility rates slipping back once the novelty wore off because "status never shifted and the underlying costs stayed high."

Instead, Krishnan proposes a more radical, holistic approach. He argues that housing must become affordable enough to support larger families, suggesting that "at some point we will surely make it legal to build more things" as the political power of older generations wanes. He also places significant weight on cultural change, pointing to France as a success story where a "pro-natalist shift" added roughly 0.3 to the TFR compared to the European average. The author posits that without this cultural component, economic incentives are merely "a handmaid's tale-esque chain of thought" that fails to address the root of the problem.

"People make the mistake of thinking of having kids as a utilitarian calculus. It's not. It's a stage of life. It is unfiltered joy... Your instagram posts about going to Maldives will not give you succour in a year or ten, but kids will."

This section is the piece's most compelling, as it bridges the gap between cold economic data and the deeply personal nature of family planning. However, the reliance on a future cultural shift or breakthrough biotech like artificial wombs to add 0.5 to the TFR introduces a degree of uncertainty. These are speculative levers that governments cannot easily pull in the short term.

The Fiscal Math of Survival

In the final section, Krishnan confronts the sheer scale of the investment required to reverse these trends, moving from theory to a brutal accounting of the costs. He sketches a scenario where the government provides a massive allowance—"$1k per child per month"—and doubles taxes on singles over 25 to compensate, a proposal that would cost the U.S. roughly $1.5 trillion annually. He admits these numbers sound "insane" but argues they are necessary to avoid a future where the pension cash flow turns negative by 2030.

The author suggests that a more efficient path might involve focusing on marginal births and investing in universal pre-K, which has shown a 10% jump in participation in places like Washington D.C., and subsidizing public IVF, which Denmark saw yield a 14x return on investment. He concludes that while the numbers are daunting, the alternative is a "doomer scenario of voluntary extinction" where the economy contracts and the social contract fractures. The piece ends on a hopeful but realistic note: "we can probably do it," provided we are willing to treat demographic stability as an economic necessity rather than a cultural preference.

"If we use those parameters, then the TFR bottoms out near 1.65 in the early 2040s, and crosses back over in a decade."

Bottom Line

Krishnan's strongest contribution is his refusal to treat declining birth rates as a purely cultural phenomenon, instead rigorously mapping the economic feedback loops that will constrain growth and fiscal stability for decades. The argument's greatest vulnerability lies in its reliance on a simultaneous cultural renaissance and technological breakthrough to solve a problem that is already accelerating; without immediate, massive structural intervention in housing and labor markets, the window to reverse the trend may close before these solutions mature.

Sources

The slow apocalypse: When will we run out of kids?

by Rohit Krishnan · Strange Loop Canon · Read full article

I.

I’m not a population expert, but there’s a ticking time bomb. Almost everywhere in the world, pretty much without exception, has lower birth rates than they used to. In fact, most of the world is below replacement (TFR or 2.2 or 2.1, depending on where you live). This is true in the US. In Europe. In Australia. Singapore. Japan. Korea. It’s reducing even in India, South East Asia, Latin America. It’s quite possible that despite the heroic efforts from Africa, we might be at replacement TFR insofar as the world is concerned right now.

And this is likely to continue downwards. In the developed world around 40% of the decline in TFR comes from childlessness, of course this varies by location, and 60% from people having less kids.

Today’s <15 set guarantees rising absolute births through ~2040 even if TFR = 1.7, but the trend is rather clear, just looking at the above numbers. Depending on which numbers you believe people think the global population will peak at like 9-10 Billion in the 2050s, then start dropping.

The reason this is a problem is that people, young working age people, are the lifeblood of the economy. A few repercussions of this population pyramid inversion:

IMF’s medium projection, assuming a Cobb-Douglas world, will cut both the level and growth rate of aggregate GDP - maybe 1% hit to the global GDP growth annually

In OECD the worker:retiree ratio doubles by 2050- this will necessitate a 5% fiscal tightening or debt

With fewer workers and more retirees we will see savings decumulate, because retirees spend more and save less1, and this will hit interest rates

And per Jones idea-production thesis, fewer young workes and researchers mean slower idea generation. OECD estimate is around 0.3% off annual TFP growth.

This is obviously scary for multiple reasons.

Lower economic growth and asset reallocation of that nature brings with it a rather uncomfortable shift in hwo people live

Per capita GDP might be less affected in the aggregate, since capital deepening might offset

And if this continues for a long while, there’s the doomer scenario of “voluntary extinction”

(For example, it makes sense that as population declines we will hit a breaking point for the economy. If demand reduces, which is literally what will happen if there’s less people, then that will affect the price. If the labour growth is negative, then the overall ...