Working-Age Population Trajectories

It has become a popular belief that demographics is destiny. There are heated debates about fertility crises that might hit countries like China, Japan, and South Korea especially hard. In the current conflict between the US and China, this affects both sides. This dashboard allows you to make your assumptions explicit and see how they shift the dynamics of the China-affiliated and US-affiliated blocks.

Working population does not automatically translate into economic prowess. In 2025 the US accounted for less than a quarter of China's population while accounting for a similar share of the world's economic output. Still, population is a significant determinant of GDP and we can use the assumptions we made on population dynamics to infer economic output in the future. This of course relies on highly uncertain projections about future per capita growth rates that can themselves be dependent on the size of the population. The striking result is not the specifics, but the robustness of the results when changing growth expectations within realistic bounds:

GDP model uses separate total-population paths and real GDP-per-capita paths for each country. Historical anchors follow World Bank constant-dollar GDP per capita and population estimate/projection series; projection years use medium-variant demographic paths and conservative continuation assumptions for GDP per capita. The China adjustment discounts both total population and working-age population for China.

Even accepting the official numbers on Chinese population and the projected higher per-capita growth rate, the US alone would still be expected to retain the lead in total GDP after losing all its allies. One is free to interpret this analysis in many different ways. The American fear of Chinese economic dominance might be overblown. The growth expectations I adopted from the World Bank might turn out to be very wrong in one direction or another. Many critiques of the method can be made. It does not account for PPP, assumes flat growth rates, and neglects cross-dependencies of per-capita growth and population growth. Yet still, going through the numbers gives an interesting, if simplified, picture of how important demographic dynamics might be.