Dan Proft explored the looming issue of global population decline in a wide-ranging interview with economist Dean Spears, co-author of the book After the Spike: Population Progress and the Case for People. Spears, a professor at the University of Texas at Austin, discussed the major shift in global demographics that could see world population peak within the next half-century before entering a long period of decline.
Despite decades of warnings about overpopulation and ecological catastrophe, Spears said the most likely future scenario now is a global population contraction—one that could be both rapid and widespread. According to projections cited by Spears, if the global fertility rate drops to 1.5 children per woman—just slightly below the current U.S. average of 1.6—the world population could shrink by roughly 10% per generation or two-thirds over the course of a century.
This isn’t theoretical. Spears noted that two-thirds of countries already have fertility rates below replacement level, and every U.S. state has at some point dropped below the rate needed to maintain population size. Even historically higher-birthrate states like Texas and Utah are not immune.
Proft and Spears discussed how popular narratives around population growth have been shaped by now-debunked predictions like Paul Ehrlich’s The Population Bomb, which forecasted famine and societal collapse due to overpopulation. Spears emphasized that such forecasts were wrong not because people stopped reproducing, but because technological and medical advances dramatically reduced child mortality and improved food production.
Now, the concern is the opposite: depopulation. But should we be worried?
Some argue that a shrinking population would benefit the environment by reducing pollution and consumption. Spears disagreed with that logic. He pointed out that nearly every meaningful improvement in environmental quality has come from changes in policy and technology, not population control. Examples include the Montreal Protocol phasing out ozone-depleting chemicals and the elimination of leaded gasoline under the Clean Air Act.
“Fewer people” is not a workable solution, Spears argued, especially since depopulation unfolds too slowly to impact near-term environmental challenges. Instead, Spears believes the world needs to start a serious conversation now—while there is still time to study the issue, consider policy responses, and reframe cultural attitudes toward family and fertility.
Spears warned that waiting for a demographic crisis to unfold before acting would likely result in panic-driven decisions. Instead, he advocated for building awareness and research infrastructure today to better understand how societies can encourage family formation and stabilize population without overreacting.
The conversation between Proft and Spears comes at a moment when cultural, political, and economic factors are all contributing to declining birth rates, including delayed marriage, affordability concerns, and shifting societal values. The segment challenged listeners to think beyond environmental alarmism and consider whether humanity’s current demographic trajectory is truly sustainable—or whether it’s time to rethink our assumptions about people, progress, and the future.
Spears’ message was clear: population growth isn’t the crisis we were told it would be. But population decline might be—and the world isn’t ready for it.