Anticipated demographic collapse turns the tables on development

For much of human history, large offspring was an important status symbol. Despotic rulers like Genghis Khan proved this: a genetic study in 2003 found that one in 200 men globally could carry his Y chromosome. More generally, all families with more resources had more children. Then, in the 18th century, the situation began to change. In the countries at the forefront of the industrial revolution, the birth rate began to fall and it was the wealthier classes that led the decline in births. In the 20th century, the inverse relationship between wealth and fertility became a fact and has been taught in universities for decades as a cardinal law of demography: as countries become wealthier, the number of children per woman falls. This assumption has shaped countless predictions about the future of the global population, starting with the UN's World Population Prospects, which estimates a global population peak at 10.3 billion in 2084. A number of researchers, however, are now questioning these numbers and in particular the pivotal notion behind them: that increasing prosperity always suppresses fertility.

Jesús Fernández-Villaverde, professor of economics at the University of Pennsylvania and a prolific researcher at the intersection of economics and demography, has recently observed large discrepancies between UN data and reality on the ground, showing that middle-income countries are now experiencing lower fertility rates than many advanced economies. In his latest study, Fernández-Villaverde points out that Thailand and Colombia both recorded fertility rates of around 1.0 births per woman in 2024, lower than those of advanced economies known for their low fertility such as Japan (1.15) or Italy (1.11). He concludes: 'My hypothesis is that by 2060 we could see rich economies as a group with higher fertility rates than emerging economies.

Last year in Colombia there were 510,000 births, a drop of 22% in five years and about 30% less than the UN forecast. From Chile to Guatemala, the situation is similar. In 2024, Mexico's fertility rate (1.55) fell below that of the USA (1.6) for the first time. But the discrepancies are not limited to Latin America. In 2024, births in Azerbaijan (1.6), Turkey (1.48) and Iran (1.44) were also below forecasts and well below the replacement rate, generally placed at 2.1 children per woman and now exceeded only by African countries. The situation in China is strange: despite its efforts, it does not go beyond 1.1 children per woman and India (1.9) is also below the replacement rate. According to Fernández-Villaverde's calculations, the combined impact of the demographic collapse in the emerging countries places the true global trajectory along the lowest path indicated by the United Nations, peaking at around 9 billion individuals in 2054, 30 years earlier than currently forecast.

A perspective that is not necessarily negative. "The fact that at some point there will be fewer people in the world is not necessarily a disaster, in fact it could be positive, considering that there are too many of us anyway," comments Roberto Poli, lecturer at the University of Trento and coordinator of a unique master's degree programme in Italy dedicated to studying the future. "Already now the planet is struggling to cope with 8 billion people, with the climate emergency, environmental and food crises and all the rest. Imagine if we were to grow to 10 billion, the impact would be even more devastating,' he points out. 'Starting to talk about a population decline gives us hope for a better future, although it is clear that the new situation will have to be managed, because we will find ourselves in a society with few young people and many old people,' he notes. The solution lies, according to Poli, in a more fluid organisation of life, so that studying is not only relegated to the first stage and working extends partly into retirement.

Europe is an interesting laboratory of the reversal in the relationship between prosperity and fertility: 'For many years, richer European countries had lower birth rates than poorer ones. This trend weakened around 2017, only to reverse in 2021,' Fernández-Villaverde notes. This reversal had already been signalled by a 2022 paper by four German scholars (Matthias Doepke, Anne Hannusch, Fabian Kindermann and Michèle Tertilt), which pays particular attention to the role of female labour. From their study, entitled 'The Economics of Fertility: A New Era', it is clear that the old models are no longer universally valid: 'In advanced countries, the relationship between income and fertility has flattened and in some cases reversed, while the relationship between women's work and fertility is now positive'. In fact, the study notes that in countries where more women work, more children are born (as in Denmark, at 1.7 children per woman) and argues that the compatibility of women's career and family goals is now a key factor, identifying four elements that facilitate the reconciliation of career and motherhood: policies that are open to procreation in any family configuration, favourable social norms, collaborative fathers and flexible labour markets. This is the starting point for public policies on childbirth.