Elon Musk warns of population collapse; asserts 'we need enough humans for Mars'

Elon Musk, who has been vocal about his stance on the global population, has issued another warning about the future of humans on Earth as well as Mars. In his recent tweet shared on January 18, the Tesla and SpaceX boss said that we should be worried about 'population collapse' and implied that a higher population is needed to ensure human settlement on Mars.

"We should be much more worried about population collapse", Musk wrote on Twitter. "If there aren’t enough people for Earth, then there definitely won’t be enough for Mars", he added in his second tweet.

In a thread, Musk also thrashed the projections of the United Nations, which in 2019 had said that the global population will be up by two billion till 2050 and up to 11 billion till 2100. "UN projections are utter nonsense. Just multiply last year’s births by life expectancy. Given the downward trend in birth rate, that is the best case unless reversed", Musk wrote. 

The falling global fertility rate

According to a 2020 report published by BBC, the fertility rate, which is the average number of births per woman, has dropped from 4.7 in 1950 to 2.4 in 2017. Researchers from the University of Washington's Institute for Health Metrics and Evaluation have predicted that this number will further dip below 1.7 by the end of this century. 

As a result, almost every country might see its population shrink by 2030. BBC reported that Japan might see its population come down to 53 million by 2100 from a peak of 128 million in 2017. Moreover, Italy's population might also fall from 61 million to 28 million along with China, which will peak at 1.4 billion but drop to 732 million by 2100. Musk also shared an NPR article where it was reported that the US witnessed a 4% decline in the number of babies born in 2020 than the previous year. In the US, the number required to replace a population is 2,100 births per 1,000 women, which fell to 1,637.5 births in 2020, according to NPR. These reports show why Musk is worried about Earth not having enough people, which would affect the population planning to settle humans on Mars.