The math behind Spain's demographic decline

The 1.12 rate and the mirage of demographic immigration

The numbers don't add up. With a fertility rate of 1.12 children per woman, Spain fails to reach generational replacement — the required level is 2.1 — and each year that passes without correction brings closer a scenario that until recently seemed like science fiction: a population reduced to a quarter of its size within a century. The figure, circulating in demographic analysis circles, has peine the debate over whether immigration is a stopgap or the prelude to a transformation of the country.

The most widely cited projection takes Spain's population down to 10 million inhabitants by 2125, of whom barely between half a million and one million would be born in Spain with several generations of roots. Put bluntly: a return to the population of the Bronze Age, but with the economy of a developed country. It is not an isolated prediction: some calculations put native fertility, excluding mothers of immigrant origin, at around 0.45-0.5 children per woman. Those figures would leave the native population in a situation of de facto extinction before the end of the century.

Precariousness or a shift in values?

Explanations are divided between those who stress the effect of women's mass entry into the labor market without a sufficient support network, and those who point to material precariousness: low wages, unaffordable housing and job instability. The personal anecdote becomes statistics when it is confirmed that couples with jobs and a desire for children postpone parenthood indefinitely for lack of the right conditions. Against this, some argue the problem predates the 2008 crisis and reflects a deep cultural shift: motherhood is no longer the dominant life project.

Immigration: the solution that doesn't fix the numbers

The figure that upsets the official narrative: a third of babies born in Spain already have foreign mothers, as El Mundo and La Vanguardia reported in May 2023, putting the combined total of immigrants and naturalized citizens at 18 million. Spanish births are partly sustained by the population that arrived from abroad. But immigrant women's fertility rates also fall with years of residence, and the filler effect does not prevent the overall rate from remaining far below replacement. Some argue the real brake on collapse will not be an official policy but the collapse of the system itself: the state that needs immigrants to pay pensions will lose its ability to attract them as public services deteriorate.

The thought experiment of empty Spain

The discussion sometimes drifts toward radical proposals, from promoting communities of native-born population in depopulated areas to outright resignation: if all civilizations eventually disappear, why should Spain be any different? The reference to the Universe 25 experiment, the mouse colony that collapsed through social withdrawal, hovers over the debate as a warning. But demography is not an inexorable destiny: South Korea, with even lower rates, has not gone extinct, and changes in public policy take decades to bear fruit, if they do.

The conclusion, for now, is uncomfortable: the data say the decline is likely, but they do not say how the inertia is broken. Those who bet on inevitability have the math on their side; those who trust in a systemic correction hope history will prove that linear projections never fully come true. Demographic projections have failed before, but no generation has had such a bad figure with such a short window for correction. The future, in any case, will be written in paychecks and nurseries before it appears in reports. That is where we should be looking.