Elon Musk speaks at a campaign rally in New York, Oct. 27. (AP-Yonhap)

Once again, Elon Musk is back to tracking South Korea's nose-diving birth rate.

With just 0.72 births per woman in 2023, South Korea has emerged as an extraordinary case study among developed countries grappling with declining fertility rates -- a sort of petri dish for what might lie ahead for societies facing a demographic crisis.

These unprecedented numbers have made the country a favorite reference point for Musk, CEO of Tesla and X and US President-elect Donald Trump’s pick to lead the newly created Department of Government Efficiency, in his increasingly alarmist warnings about an impending worldwide population collapse.

"2/3 of Korea will disappear every generation," Musk wrote on X Wednesday, retweeting a report from Think Global Health. The shared screenshot, based on World Bank data, shows South Korea's fertility rate plummeting from over 5 births per woman in the 1960s to today's record lows. The screenshot's caption cites long working hours, low wages, and falling marriage rates as key factors.

According to Statistics Korea, the country's projected fertility rate for 2024 is 0.74 -- a slight uptick from last year, though still nowhere near the OECD average of 1.51, or the 2.1 needed for a stable population.

This isn't the first time Musk, currently the world's richest person, sounded the alarm about South Korea's demographic trajectory.

At October's Future Investment Initiative in Riyadh, he warned the Korean population would shrink to "about a third" based on current trends. In September 2022, he claimed the country was "tracking to lose about half its population roughly every generation." Earlier that year, he singled out South Korea and Hong Kong as "experiencing the fastest population collapse."

Musk, a father of at least 11 children with three different women, has turned falling population numbers into something of a personal mission over the years, calling it "the biggest danger civilization faces" and "a much bigger risk than global warming." His message has made him a poster child of the pronatalist movement, which has lately gained traction globally in its push to get people to have as many children as they can to counter demographic decline.

In May, South Korean President Yoon Suk Yeol declared the fertility crisis a "national emergency" and announced he would launch a new government ministry to tackle the problem.