A study in Lancet says the data are starting to show large reductions in global fertility rates, which are likely to lead to declining population growth and then a declining population as the century wears on.

The global TFR in the reference scenario was forecasted to be 1·66 (95% UI 1·33–2·08) in 2100. In the reference scenario, the global population was projected to peak in 2064 at 9·73 billion (8·84–10·9) people and decline to 8·79 billion (6·83–11·8) in 2100. The reference projections for the five largest countries in 2100 were India (1·09 billion [0·72–1·71], Nigeria (791 million [594–1056]), China (732 million [456–1499]), the USA (336 million [248–456]), and Pakistan (248 million [151–427]). Findings also suggest a shifting age structure in many parts of the world, with 2·37 billion (1·91–2·87) individuals older than 65 years and 1·70 billion (1·11–2·81) individuals younger than 20 years, forecasted globally in 2100. By 2050, 151 countries were forecasted to have a TFR lower than the replacement level (TFR <2·1), and 183 were forecasted to have a TFR lower than replacement by 2100. 23 countries in the reference scenario, including Japan, Thailand, and Spain, were forecasted to have population declines greater than 50% from 2017 to 2100; China’s population was forecasted to decline by 48·0% (−6·1 to 68·4). China was forecasted to become the largest economy by 2035 but in the reference scenario, the USA was forecasted to once again become the largest economy in 2098.

Lancet

In my time living, working and traveling in Southeast Asia, I saw firsthand that at least some highly educated women are choosing to prioritize career over marriage and children. That pattern may be taking hold on a larger scale as larger countries move from middle income to higher income. Opportunities and choices for women are a good thing, of course, but there are some concerns about who will do the work and pay the taxes in such a world. We’re fretting about the effects of automation on employment, but if the work force is going to shrink anyway, and the jobs that do remain are going to require more education and skills, it seems like there is an opportunity to try to pair the pace of automation to the pace of natural work force reduction. The solutions are nothing new – we need to invest in childcare, education, training, research and development, unemployment insurance, and strong pension systems. We may need stronger measures to share the wealth, like a universal endowment at birth or a universal basic income.

Then there’s environmental impact. Malthus aside, without policy changes the effects of a population that is becoming more affluent and consuming more will probably outweigh the effects of a shrinking human population. We can’t just keep paving the world, pumping the groundwater, massively altering the oceans and atmosphere, driving more and eating more meat forever and expect it not to catch up to us.