The Birth Dearth

The most important chart in demography has no drama in it at all. No crash, no spike, no crisis year to circle. Just lines sloping downward — some gently, some like a cliff face — as the number of children the average woman bears falls on every continent, in every kind of country, under every kind of government.

In 1960 the global average was around five children per woman. Today it is a little above two, hovering near the level at which a population merely replaces itself. Nothing else in this dataset — not income, not life expectancy, not technology — has changed so universally, so fast.

South Korea is the extreme case, and the one demographers cannot stop staring at. In 1960 the average Korean woman had roughly six children. Fertility fell below replacement in the early 1980s, then below one child per woman in 2018 — the first country ever to cross that line — and it has kept falling since, to below 0.8. At rates like these, each generation is less than half the size of the one before it.

China took a different road to a similar place. The one-child policy, imposed in 1980, is the most famous fertility intervention in history — yet look closely at the chart and the steepest stretch of China's decline comes in the 1970s, before the policy existed. Prosperity, cities and schooling were already doing the work that coercion later claimed credit for. The policy was lifted in 2015; the birth rate barely stirred.

The one-child policy's greatest secret is that China's fertility collapsed before it began.

What is striking is not any single country but the unanimity. Catholic Italy and secular France, rich Japan and middle-income Brazil, democracies and autocracies alike have converged toward small families. Iran's fertility fell about as steeply as China's with no one-child policy at all. Wherever women gain schooling, cities and some measure of choice, the same decision gets made — millions of times over, in private.

The age wave

A fertility decline is not felt when it happens. It is felt thirty years later, when small generations reach working age, and sixty years later, when they retire with no one behind them. Japan arrived first: below replacement since the mid-1970s, it is now the world's oldest large society, with almost three in ten citizens aged 65 or over. Italy is close behind. Korea and China, whose declines came later but moved faster, are aging at a pace Japan never experienced.

The mirror image is the working-age share — the fraction of a population between 15 and 64 that does the earning, the caring and the taxpaying. China's working-age share crested around 2010 and has been sliding since; the era in which a swelling workforce flattered every Chinese growth statistic is over. Nigeria's story is the reverse: its working-age share is still climbing, and the demographic dividend that powered East Asia's miracle is, in principle, still ahead of it.

None of this is destiny, but the lines are stubborn. No rich country has yet returned to replacement once fertility fell well below it, and the policy record — baby bonuses, parental leave, housing subsidies — is a catalogue of expensive, marginal effects. What the data suggests is that the world faces not the population explosion the twentieth century feared, but a long, slow contraction that begins at different moments in different places.

Africa's transition is real but later, and its populations will keep growing for decades yet. The question the chart poses is not whether the birth dearth arrives everywhere. It is what each society does with the interval before it does.

Every figure identifies its source. See SPHRE sources and methodology.