As one of the 8.23 billion people on Earth, you likely have thoughts about the global population reaching a record 10 billion in the coming decades. You might not be thrilled—especially with climate change already causing havoc and crowded commutes feeling like packed sardine cans.
But according to Dean Spears and Michael Geruso, researchers at the University of Texas, the real concern isn’t overpopulation—it’s depopulation. Birth rates have been falling worldwide for centuries, and more than half of countries, including India (the most populous nation), now have fertility rates below replacement levels. While the total population has grown due to lower infant mortality, we’ll soon hit a peak before numbers drop sharply—the “spike” in question.
Today, most people live better than ever before, thanks to progress driven by human ingenuity—what the authors call “the ultimate renewable resource.” Spears and Geruso argue that future generations living in a world of just a few billion people will have worse lives than we do now. They believe stabilization, not decline, is the best path forward—which means we need more babies.
Climate change is so urgent that depopulation will come too late to make a real difference.
The book After the Spike challenges common assumptions. It refutes population doomsayers like Malthus and Paul Ehrlich, showing that global fertility isn’t tied to wealth, contraception, or women’s rights. Government policies—whether forcing people to have children (like Romania’s abortion ban) or discouraging them (like China’s one-child policy)—only have short-term effects. Even supportive policies, like Sweden’s generous parental leave, haven’t reversed the trend. Sweden’s population will start shrinking by 2051.
One major argument the authors counter is that lower birth rates are good for the planet. In reality, depopulation won’t happen fast enough to curb climate change. The difference in emissions between today’s population and the peak is negligible. Fewer people won’t help the climate, but it will mean fewer hands to clean up the mess—like removing excess greenhouse gases. Solving big problems—from curing diseases to reversing environmental damage—requires the ideas and labor of large, connected societies.
So why are people having fewer kids? The reasons are complex—cultural, biological, economic, and social—but the best explanation might be a satirical Onion headline: “Study Finds American Women Delaying Motherhood Because the Whole Thing Blows.” As life offers more fulfilling options, the sacrifices of parenting seem less appealing. Today, it’s easier to live meaningfully with fewer or no children—something Gen Z knows well.
If we want a good future for our descendants, we need a stable, sizable population. The alternative—a shrinking world—could mean fewer solutions and a harder life for those who come after us.How can we address population decline? Spears and Geruso propose a radical solution: rebuilding society around care, where parenting receives such strong social, cultural, economic, and medical support that it becomes a source of joy rather than an exhausting challenge. Had this been my reality ten years ago, I might have had the large, lively family I sometimes long for. Whether humanity can achieve this in time to prevent depopulation seems uncertain, but After the Spike leaves us with one clear message—we should believe in ourselves.
After the Spike: The Risks of Global Depopulation and the Case for People by Dean Spears and Michael Geruso is published by Bodley Head (£20). To order a copy, visit guardianbookshop.com. Delivery charges may apply.
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