Is U.S. Birth Rate Falling? Elon Musk Warns of Population 'Collapse'

Elon Musk posted two tweets yesterday outlining his concerns about declining birth rates in the U.S., sparking discussion about what he called "the biggest threat to civilization"—population collapse.

One of Musk's tweets included a line graph from The Wall Street Journal visualizing the U.S. total fertility rate from the 1940s to today, with total fertility rate being an estimate of the average number of babies a woman would have in her lifetime.

In order for a generation to replace itself that rate needs to be about 2.1. The graph clearly shows a large spike to around 3.7 in the post-war baby boom era of the 50s, before sharply declining below 2. The rate recovered somewhat up until about 2008 before falling again, and today the rate appears to be about 1.6 according to the graph.

"USA birth rate has been below min sustainable levels for ~50 years," Musk wrote. The tweet had gained more than 130,000 like and nearly 20,000 retweets as of Wednesday morning.

Elon Musk
Elon Musk pictured at the site of a Tesla factory in Germany in September, 2020. Musk has expressed concerns about low U.S. birth rates. Maja Hitij/Getty

Previously Musk has argued that the environment would be "fine" even if the world's human population doubled.

It is well known that the U.S. birth rate is declining and has been since 2008—a fact observed by the U.S. Census Bureau last year.

Economists have referred to this decline as something of a mystery. The 2008 decline coincided with the global financial crisis of that year which led to one of the worst U.S. recessions ever.

However, the rate did not increase in the years that followed even when the economy improved. In fact, as of 2020 the U.S. birth rate was 55.8 births per 1,000 women between the ages of 15 and 44, a decline of almost 20 percent from the rate of 69.3 in 2007 according to a Econofact article written earlier this year by three college and university economists.

The decline is present across many demographics. Births have fallen among women with and without college degrees, among married and unmarried women, and among white, black, and Hispanic women, the economists wrote.

The question is what effect a declining birth rate has and how damaging it can be. That depends on who you ask.

Human beings are obviously essential for society. Today's babies will be staffing the hospitals and nursing homes of tomorrow; they'll pay the taxes that keep the government running; and they'll buy the homes and invest in the stocks that the adults of today have put all their savings into.

A lack of babies is linked to an aging population, in which there are fewer and fewer people of working age, leading to a shortage of qualified workers and supply-and-demand economies that can't fill the roles to supply that demand, leading to higher labor costs and declining business expansion, Investopedia states.

"If you have low or negative population growth you can have a shrinking population, and that's led to weaker GDP growth in the past," Caroline Hartnett, a demographer and sociologist at the University of South Carolina, told Popular Science last year.

Some argue that a shrinking population is beneficial: that it is a marker of women's reproductive rights; that it will lead to a greener, healthier world with fewer people burning through finite natural resources.

"Having a child is seven times worse for the climate in CO2 emissions annually than the next 10 most discussed mitigants that individuals can do," analysts at Morgan Stanley said in 2021, CNBC reported at the time. One 2017 Swedish study found that having one fewer child per family could save approximately 58.6 metric tons of carbon per year in developed nations.

Indeed, while some are baffled by a declining population, environmental concerns are cited as a top reason why some people are choosing not to have kids.

"I refuse to bring children into the burning hellscape we call a planet," one teacher told CNBC last year.

In any case, immigration, which tends to bring in young adults, can be an effective way of offsetting domestic low fertility rates. In fact, were it not for immigration the population of almost every rich country in the world would shrink, according to a New Statesman article last year.