Over the years, SpaceX CEO Elon Musk has repeatedly warned that humanity is headed for disaster due to falling global birth rates.
Musk believes there is a solution to prevent the extinction of the human species, and shared his opinion with his more than 70.6 million followers on Twitter.
"There is a 100% chance of extinction of species due to the expansion of the Sun," Musk wrote. “Unless humanity makes life multi-planetary.”
And that may be a bad omen for his bold plans to one day build a city on Mars.
“If there aren’t enough people on Earth, there won’t be enough people on Mars either,” he added in a tweet with a sad smiley face.
Back in 2020, experts warned of a "staggering" decline in the number of births worldwide. According to the BBC, by 2100, the birth rate could lead to a decline in the population.
The COVID-19 pandemic has only accelerated this trend, despite some initially predicting that the pandemic would spark a baby boom.
Musk has long held the unorthodox belief that this is the number one threat humanity faces in the 21st century.
"I think one of the biggest risks to civilization is the low birthrate and rapidly declining birthrate," he told The Wall Street Journal's board of directors last year. “And yet so many people, including the smart ones, think that there are too many people in the world and think that the population is growing uncontrollably.”
"Please look at the numbers - if people don't have any more children, civilization will collapse, mark my words," Musk pleaded at the event.
The billionaire CEO has big plans for our species, not the least of which is sending 1,000 Starships to build a sustainable city of one million people on Mars.
But now, with fewer future Mars inhabitants being born on Earth, Musk now seems to worry that his dream of having humanity go on interplanetary travel — his solution for our species' long-term survival — may never come true.