Fertility in the Face of the Environmental Crisis

As birth rates decline around the world in the face of economic, social and health pressures, economists have found that environmental concerns also influence decisions about whether to have children – and how many. 

This article is published in partnership with CNRS Le Journal. 

In France, as across much of the world, people are having fewer children. In 2025, 645,000 babies were born in France – 24% fewer than in 2010, the most recent peak in births, according to France’s National Institute of Statistics and Economic Studies (Insee)1 . The total fertility rate, which stood at 2.0 children per woman in 2014, fell to 1.56 in 2025, the lowest level since the end of the First World War. 

This decline is evident across Europe, where the average fertility rate is around 1.4 children per woman, and more broadly across high-income countries, as well as an increasing number of middle-income nations. In France, people say they want fewer children – particularly those belonging to the younger generations – with a growing share saying they intend to have no children or just one. Over the past 20 years, the number of children under-30s say they would like to have has fallen by 0.6 on average: from 2.5 to 1.9 among women and from 2.3 to 1.8 among men. 

France's population continued to grow slowly, by around 0.25%, and the country still recorded a positive natural increase in 2024, with roughly 17,000 more births than deaths. In 2025, however, natural increase turned negative for the first time since the Second World War, with around 6,000 more deaths than births. Declining birth rates have now become a prominent concern in political discourse: in early 2024, President Emmanuel Macron called for a "demographic rearmament," presenting a revival in the birth rate as one of the pillars of France's national "power."

• 1

  Thélot H., « Bilan démographique 2025. En 2025, le solde naturel en France est négatif pour la première fois depuis la fin de la Seconde Guerre mondiale », Insee Première n° 2087, janvier 2026.

Anxiety: the enemy of fertility?

So, what lies behind the fall in fertility rates? The answer is of course multifaceted, but it appears to be linked to a range of unfavourable social and economic conditions. A United Nations study investigating the barriers to having children across 14 countries found that respondents most often cited economic difficulties: financial constraints (39%), unemployment or job insecurity (21%), housing problems (19%), and difficulties accessing childcare (12%). The unequal distribution of domestic work between women and men was also cited, by 13% of women and 8% of men. 

Health-related issues also play a role, including chronic illness and infertility, cited by 12% of respondents. In France, nearly 15% of couples experience difficulties conceiving. The rising age at which women have their first child – now around 29 – as well as environmental pollution and limited access to medically assisted reproduction can all affect fertility. 

Fécondation in vitro réalisée au sein d’une clinique de fertilité. © ARTPhoto / stock.adobe.com

But that is not the whole story: people are not only having fewer children and wanting fewer children because of immediate economic or health concerns. They are also worried about the future – socially, politically and environmentally. 

According to France’s Institute for Demographic Studies (Ined)2, 35% of people aged 25 to 39 who are very worried about the prospects facing future generations say they will “probably” or “certainly” have a child, or another child, compared with 46% among those who are less worried. The former also want, on average, 0.11 fewer children.

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  Bouchet-Valat M., Toulemon L. 2025 (juillet-août). Les Français·es veulent moins d'enfants. Population & Sociétés, 635

The economics of family and fertility

Paolo Melindi-Ghidi and Thomas Seegmuller, economists at Aix-Marseille School of Economics (AMSE), set out to investigate how pollution might affect fertility decisions. Until now, economists have largely explained declining birth rates in wealthy countries in financial terms. “The economics of the family, building on the work of Nobel laureate Gary Becker, has explained this trend in terms of the trade-offs people make between their personal preferences and the costs those preferences entail – in financial terms, as well as in terms of time and education,” explains Thomas Seegmuller.

People derive satisfaction from the choices they make within the limits imposed by their resources – in other words, “If a couple wants to have children, they weigh their desires against the costs. And those costs vary enormously from one country to another: raising a child in Manhattan, for example, is far more expensive than in a sub-Saharan African country.” Thomas Seegmuller continues, “Research has also shown that as countries become more developed, people tend to invest more heavily in their children’s education. As a result, they choose to have fewer children; this is the economic relationship between ‘quality’ and ‘quantity’.” 

Paolo Melindi-Ghidi adds: “This demographic transition has been observed in most developed economies: in the early stages of a country’s development, falling mortality rates lead to rapid population growth while birth rates remain high. Then, once a certain level of development is reached, fertility rates begin to fall.”

A socioeconomic paradox

Yet when the two researchers compared data from different US states, they found that the correlation between fertility rates and pollution levels was at least as strong as the more familiar relationship between birth rates and economic development. 

“We started with two observations,” says Thomas Seegmuller. “Firstly, studies in psychology and behavioural science have shown that environmental concerns are playing an increasingly important role in fertility decisions. Secondly, we found that in the United States, states with the most carbon-intensive economies, such as Texas, also tend to have the highest fertility rates. Conversely, states such as California, where carbon intensity is lower, generally have lower fertility rates.” 

At first glance, the finding appears paradoxical: one might expect people living in the most polluted states to be more reluctant to have children. “People’s environmental concerns are closely related to the degree of environmental degradation, particularly the carbon intensity of the economy – that is, the amount of carbon dioxide (CO₂) emissions generated per unit of gross domestic product (GDP). But we found that the less pollution there is, the more citizens tend to support stronger environmental regulations. Conversely, when carbon intensity is high, more people believe that such regulations harm jobs and the economy.” The conclusion is striking: the lower the carbon intensity, the stronger people’s environmental concerns tend to be. “That surprised us,”  Thomas Seegmuller acknowledges. “Our aim then became to develop an economic explanation that could account for this finding.” 

© Aaron Burden / Unsplash

Conflicting sources of satisfaction

On this basis, the researchers added an environmental dimension to the traditional quality-versus-quantity framework: an environmental index measuring the ratio between the production of green goods – electric vehicles, renewable energy and so on – and the production of polluting goods, such as conventional combustion-engine cars. The greater the share of green production, the higher the environmental index and the lower the economy’s carbon intensity. The index captures the value households attach to environmental quality when making decisions. In other words, it becomes another factor in the trade-offs they make, alongside their assessment of financial and other costs.

 “One of the key points of our model is to show that this has a direct impact on the decision about how many children to have – but, more importantly, that these variables cannot be separated.” In a conventional economic model, the number of children and the state of the environment can be treated independently: people derive satisfaction from having children, and separately derive satisfaction from living in a high-quality environment. Here, however, the satisfaction associated with having children also depends on the quality of the environment. 

“Another key contribution of our research,” continues Paolo Melindi-Ghidi, “is the idea that preferences for the number of children and environmental concerns can either complement or substitute for one another. The most interesting results emerge when the two sources of satisfaction are substitutes. The reasoning is as follows: a less carbon-intensive economy is associated with stronger environmental concerns and better environmental quality. If this improvement in environmental quality substitutes for having children in people’s preferences, then the number of children they want decreases.” In other words, Thomas Seegmuller adds, “I’m going to have fewer children because I’m already happy that the environment is improving”.

There is, however, another side to the relationship between population and the environment: the more people there are, the more pollution there tends to be – unless we fundamentally change the way we live and consume. “According to the economic literature examining the effects of population growth on environmental degradation, a declining population might, in fact, not be a bad thing,”  Thomas Seegmuller concludes. Birth rates and the environment, it seems, are an equation with no simple solution.