By 2064, the Global Population Could Be Halved in a Worst-Case Scenario—but Housing Affordability Poses a Far More Immediate Risk

The global population could be cut in half in just 40 years, under a worst-case scenario modeled in a new study.

However chilling the headline findings are, the authors of the report, published in "Chaos, Solitons & Fractals," are careful to explain that current trends are stable.

“We emphasize that the current trajectory remains relatively stable and does not imply imminent collapse,” Alessio Zaccone, one of the researchers behind the study, writes in an essay about his work. 

Instead, “the most provocative part of our paper explores hypothetical future scenarios,” he says. 

Those findings offer an illustration of how sensitive population dynamics can become when systems are pushed past their limits—be it through war, climate collapse, pandemic, or other global crisis. 

And while this study focuses on global shocks, it builds on a growing body of research that shows the ways in which housing scarcity and affordability challenges may already be doing exactly that—pushing young families past their financial limits, and forcing them to opt out of parenthood altogether.

What the study found

The study revisits one of the most famous predictions in population science: The 1960 “doomsday equation” by Heinz von Foerster, which mathematically extrapolated that the human population would diverge toward infinity on Friday, Nov. 13, 2026.

Of course, that hasn’t happened—even though the doomsday is a mere few months away. Instead, global fertility rates are in decline, with the U.S. reaching a record low in 2025 at 1.57 births per woman—well below the replacement rate of 2.1.

Zaccone and his colleagues' study offer insight into why.

“In our baseline analysis, the current global trend does not produce a catastrophic singularity like the one predicted by von Foerster and co-workers, because the governing parameter remains in a stabilizing regime,” Zaccone writes.

In layman's terms, Zaccone is pointing to the fact that population models have long relied on rigid, single-speed formulas that assumed humanity would either skyrocket forever or level off. His new model, however, proves that human societies are far more sensitive, capable of sudden regime shifts based on how heavily the environment strains our capacity to survive.

Despite that fragility, Joel Berner, senior economist at Realtor.com®, says there’s no reason to panic. But there may be reason to take pause.

“Keep in mind that these doomsday scenarios have a lot of assumptions baked in about things going catastrophically wrong and take them with a grain of salt,” he says. “But also understand that the trends toward population decline have already begun.”

Is the housing market to blame for falling fertility rates?

The current demographic crisis, while much more contained than the new study’s possible future, contains a bitter irony for the real estate market. While the economy relies on population growth to sustain itself, the housing market may be choking out that growth, creating a dangerous feedback loop.

Just look at when the current trend in U.S. fertility rates reversed from solid growth into decline: the 2008 financial crisis. It was during this era of widespread financial hardship that fertility fell below replacement rates and has never recovered since.

A groundbreaking study published last year adds weight to this trend, finding that rising housing costs were responsible for a staggering 51% of the total U.S. fertility rate decline between the 2000s and 2010s. Those findings build on a 2011 study that found that among nonhomeowners, a 10% increase in home prices leads to a 1% decrease in births in an average metropolitan area.

That correlation becomes particularly alarming when applied to recent history. Between 2019 and 2025, U.S. shelter prices skyrocketed by 34%, while childcare costs rose a whopping 39%, effectively pricing young couples out of the family-building market.

University of Pennsylvania economist Jesús Fernández-Villaverde echoed this relationship in a recent interview in The Atlantic.

When asked why global fertility rates are falling, Fernández-Villaverde pointed to changes in social norms, a movement toward service-based economies, and housing costs.

“In many countries, not in all, housing is at historical heights in relative price. That also limits the ability of families to have more children,” he said.

What depopulation means for the housing market

But while there is a clear relationship between rising housing prices and falling fertility rates around the world, Berner is careful to emphasize that this isn’t the same as a real carrying capacity limit, as examined in Zaccone’s new study. 

“Housing shortages do not equate to real physical carrying capacity,” he explains. “They are a price-driven market result that policy could address, not a true cap on how many people the planet can support.”

It’s good news for anyone worried about depopulation and the housing market, because it means there is no limit to the number of solutions we might engage to solve the crisis.

“The government could subsidize new construction,” Berner offers as just one possible solution. “While there would likely be a crash in existing home values, we could end up in a place where there are enough places for everyone to live affordably and have children.”

At the same time, though, it underlines the importance of taking action now. As Berner notes, a depopulated future will fundamentally alter the nature of real estate. 

“It is probably not a safe assumption that homes will appreciate as strongly during periods of declining population as they have traditionally,” he says.

Japan, which is currently 20 to 30 years ahead of the U.S. demographic curve, offers a glimpse into what Berner describes.

As the country’s population aged, the housing market has been hit with haunting side effects, including the departure of Japanese builders to other markets and the rise of abandoned homes.

These properties, known as akiya, have captured international headlines for their "too good to be true" price points—some selling for less than $10,000—and their setting in idyllic, traditional landscapes.

Charles Yuji Horioka, a Nakahara Prize-winning economist and research professor at Kobe University, told Realtor.com in March that part of what’s driving that is a mismatch between population and demand.

“Jobs and also educational opportunities are much more and much better in big cities,” Horioka noted. As shrinking younger generations migrate to urban centers, too few people are left behind to maintain countryside properties.

“That has led to a sort of decline in land and housing prices in rural areas,” he explained

Without policy intervention or demographic rebalancing, U.S. real estate risks hitting a similar wall, according to Berner.

“Especially in markets with high concentrations of senior citizens, the buyer pool may be shrinking and homes may not hold their value in the same way that they have historically,” he says.

Through that lens, the most immediate threat to both fertility rates and the future of the housing market isn't a distant planetary limit—it is affordability.