The typical person in Japan is 49. The typical Nigerian is 17.
Median age, selected countries. Years.
- The rich world had fewer children decades ago and now lives longer, so its people are old and getting older.
- Much of Africa and South Asia still has high birth rates, so half the population is barely out of school.
- These ages are already locked in: the workers and retirees of 2050 are alive today.
Demographics is destiny on a thirty-year delay. The old countries will fight over too few workers; the young ones must create hundreds of millions of jobs, or watch their people leave to find them.