Population Collapse

Elon Musk warns that the danger facing humanity is too few babies. For years he has argued that falling birth rates are the threat societies should fear most, and he has called population collapse a bigger risk to civilization than global warming. The idea rests on the replacement rate: demographers, who study populations, estimate that a population holds steady over the long run when women average about 2.1 children each, enough to replace both parents with a little extra for children who do not reach adulthood. When birth rates stay below that line for decades, a population shrinks and grows older.

What is Population Collapse?

Elon Musk uses the phrase for a steady, compounding fall in the number of people, caused by birth rates that stay below replacement. Above the replacement level a population tends to grow. Below it each generation is smaller than the last, and the effect builds the way compound interest does, slowly at first and then steeply. The phrase describes a long slide that, if nothing changes, would leave far fewer people decades from now than most forecasts expect.

Why Elon Musk Believes it

Elon Musk argues that public worry points the wrong way. He has said many smart people assume the population is growing out of control when the numbers show the opposite. In his view the lasting danger is running out of people, because each smaller generation has fewer children of its own. He ranks it above almost every other risk he talks about and ties it to the long-term survival of civilization.

How it Works in Practice

The mechanism is simple math. If a generation of couples averages well under two children, the next generation is smaller and the one after that smaller still. People are also living longer, so the share of older people rises while the share of young workers falls, and a shrinking base of workers supports a growing number of retirees. Elon Musk calls it a slow-moving problem because it is easy to shrug off from one year to the next and hard to reverse once it sets in: the parents of tomorrow are the children not born today.

The Numbers Behind It

The OECD, a group of 38 mostly wealthy countries, reported that its members averaged 1.5 children per woman in 2022, less than half the 3.3 they averaged in 1960 and well below the replacement level.

Elon Musk has also put money behind the issue. In 2021 he gave $10 million to the University of Texas at Austin to help set up the Population Wellbeing Initiative, a research group that studies demography, and he points to his own large family as an example.

Population Collapse Today

Elon Musk raises the idea most often in his posts. Through 2024 he posted on X that birth rates continue to plummet and that population collapse is coming, and that extreme birth rate collapse is the biggest danger to human civilization by far. The worry also runs through his other goals: his case for making humanity multiplanetary assumes there will be enough people to build and run a civilization on two planets.

What Comes Next

Because each generation sets the size of the next, Elon Musk argues that any response has to start early. He has called for cultural and government attention to birth rates, has funded research, and champions the cause in his posts and through his own family. The question he keeps raising is whether societies will treat low birth rates as a long-run risk before the trend becomes too hard to reverse.

The Bottom Line

Population collapse is Elon Musk's argument that the number of children born is one of the most basic inputs to a civilization. Birth rates in most wealthy countries are now well below replacement, the trend he has asked societies to take seriously.