In the latest edition of its World Population Prospects, the United Nations Department of Economic Affairs offers various possible scenarios for countries’ populations. In the case of the US, both the low-fertility projection and the zero-migration projection see a decline in population by the end of the century of around 16%, from the current 336.5 million to around 280 million. But that is not the UN’s base case. In its medium-fertility variant, the US population rises 17% to 394 million by 2100. In a high-fertility scenario, it rises to 541 million.

By contrast, the UN offers no scenario in which China’s population does not decline. Best case, it falls by a fifth. Base case, it declines by 46%, to 771 million. Worst case it falls by nearly two thirds, to 494 million. (You will notice that would be below the end-of-century total for the US in the high-fertility scenario.)

As Nicholas Eberstadt and Peter Van Ness of the American Enterprise Institute have pointed out, this is major revision by the UN. Twenty years ago, the Population Prospects projected China’s population to rise from 1.28 billion in 2001 to 1.43 billion this year and then to keep rising to a peak of 1.45 billion in 2031. The 2031 peak was still there in the 2019 World Population Prospects. Now, according to the UN’s latest medium projection, the peak will be in just two years’ time and the 2050 population will be 100 million less than previously forecast.