Very few people live beyond the age of 100. If everyone suddenly stopped having children, it’s likely that in about a century there would be no one left on Earth. However, the population would fall gradually at first.
Even if births suddenly stopped worldwide, the population would decline slowly at first, says Michael Little, a distinguished professor of anthropology at Binghamton University in the U.S.
He explains that eventually there wouldn’t be enough young people to fill essential jobs or to replace retiring workers. That would trigger a rapid breakdown of communities around the globe. Food supplies would dwindle, but there would also be fewer people to feed.
Little suggests that in 70 to 80 years (rather than 100), the planet could be nearly empty because of shortages of food, clean water, and medicine—basically everything we now take for granted.
Of course, a sudden stop in births is extremely unlikely without a global catastrophe. Kurt Vonnegut explored one scenario in his novel Galápagos (1985): a contagious disease that renders everyone of reproductive age infertile.
Another possibility is nuclear war, which could leave no survivors. Films and books have explored that scenario and other post-apocalyptic themes: space travel, reproduction challenges, collective despair, and the loss of personal freedom.
In the 1960s and 1970s, people worried that overpopulation would cause disaster. That anxiety fed many dystopian books and films, as reported by Science Alert.
But for now, we are on track for 10 billion people
Currently, the global population is still growing, although the rate of growth has slowed. Experts predict the world population will peak at about 10 billion in the 2080s (we are currently at 8 billion).
As these changes unfold, maintaining a balance between young and old will be crucial: young people drive the economy and society, while older adults often need support from younger generations.
In many countries today, women are having fewer children than in previous generations. Many people choose to have fewer children than their parents did, or none at all.
Moreover, an increasing number of men are facing fertility issues that make it harder to father children. This is another factor contributing to population decline, Little says.
Neanderthals also went extinct
Our species, Homo sapiens, has existed for about 200,000 years. That’s a long time. But like all animals on Earth, we are at risk of extinction.
Remember what happened to the Neanderthals, our close relatives. Their lineage goes back at least 400,000 years. Later, members of Homo sapiens interbred with them. Ultimately, Neanderthals gradually declined and went extinct around 40,000 years ago. Researchers say Homo sapiens were better at sustaining and increasing their population than Neanderthals.
If humans did go extinct, other animals would have new opportunities to thrive on Earth. On the other hand, it’s sobering to think that humanity’s achievements would vanish with us.
Little says steps to ensure a long future for humanity include addressing climate change and preventing wars.
