According to the UN, the world population will reach 8 billion this month of November 2022. When I was born, the world population was 2.5 billion. When I went to university, one of our professors told us we lived in a ‘full world’. By 2050, the UN tells us, we will be 10 billion.

Several decades ago, when there was still some belief in the possibilities of ‘development’, population growth was a hot item since in many poor countries GDP did go up but this ‘progress’ totally disappeared due to population growth.

Today, the topic has all but disappeared from public debate. In a recent exchange organised by the Great Transition Initiative Ian Low spoke of ‘the elephant in the room’, with some good arguments. Fear does not concern a food shortage anymore but the carrying capacity of the Earth in view of the current climate change and loss of biodiversity.

The world population is still growing, though at a much slower rate. The question now is: how do we have to assess the numbers and the demographic development? Is it indeed worrying? Do we have the capacity to manage it? Can we produce enough food or do we have to re-think malthusianism? Can it hinder the sustainability of our planet?

These are very difficult questions and there are huge divergences in all the answers. All one can say at this stage, before deciding on what side to take, is that yes, we need to urgently discuss this matter. People who think we have a problem are not necessarily neo-malthusianists and do not want to eradicate people of color or poorer populations. They very often are honestly concerned about the carrying capacity of the planet. They do not only think of food, but also of all the natural resources we need to organise life in an equitable way. People who think there is no problem trust either in our innovative capacities or in a return to bio-agriculture, stepping back on industrialisation and going back to the villages of a century ago. Population growth is indeed ‘the elephant in the room’. Climate change and loss of biodiversity are very serious problems and not one element that may contribute to worsening the situation should be overlooked.

So yes, population growth should be back on the agenda, less because of malthusianism than for ecological reasons. It is the major contributor to worsening overshoot in all income categories, research says. The most difficult point in the whole debate is that even if you think population growth is problematic, there is no short-term solution. All one can do is promote family planning and the empowerment of women, two very welcome steps but without immediate consequences. Results will only be seen in ten to twenty years, at best. And population growth is slowing at any rate. While the fertility rate of women was 3.2 in 1990, it now is 2.4 and the estimates for 2050 are 2.2. To avoid the decline of the population, the fertility rate should be 2.1. Positive steps in favour of women are very slow to show their results.

A second problem is that too many debates are still on the either-or question. You believe climate change can only be stopped by tackling capitalism and consumption of the rich, or you opt for stopping population growth. You either are an ‘eco-modernist’ believing in a technological fix or you want to keep everything ‘natural’. Are these choices necessary? Why not opt for a combination of one and the other? Why not promote family planning, the reduction of consumption, and re-examine production in industry and agriculture? Are the problems of climate change and loss of biodiversity not serious and urgent enough to take immediate steps in all directions?

The food problem can be solved, for sure. Whether we opt for ‘eco-modernism’ with bio-engineering or for bio-agriculture or both, there does not seem to be any serious argument to question the sustainability of food production. Bio-agriculture has lower productivity, so it seems it will need much more agricultural land, but what if land for livestock is seriously reduced? Why not invest massively in vegetable ‘meat’ which could free much land for crop farming? And if one opts for bio-engineering, why should it necessarily lead to monoculture and monopolistic use of fertilisers? Can a green revolution not be accompanied by respect for peasant rights? With ten billion people on this planet, the demands on the natural system will be overwhelming, but solutions are surely possible. No need to go back to malthusianism.

I have been arguing for years that social justice can open the door to more environmental justice. In the first place because the wealthy and middle classes will never willingly accept to take a step back on comfort and luxury, and secondly because the billions of poor even cannot take any step back. They are still lacking all kinds of resources for a life of dignity. And while the poor necessarily contribute to CO2 emissions – living in old non-insulated houses or using polluting cars – the real big polluters are the rich. They have appropriated the earth’s bio-capacity. This means that fighting inequality will have to become a major element of the fight against climate change and in favour of biodiversity. Today, too many proposals and actions are still focused on the lower classes – leaving no one behind – while the rich can continue to use their private jets. Taxing the rich and banning some practices will have to be a necessary and urgent element of environmental policies. And yes, poverty will have to be tackled, since no policy will ever be widely accepted if it does not lead to more prosperity, welfare and well-being.

It goes without saying that all people have a right to a decent way of living with an adequate living standard. This does not mean living like the rich or the higher middle classes but certainly living like the lower middle classes. It is from that perspective that we have to wonder whether the Earth has the carrying capacity, knowing ten billion people will require a lot more energy, water and food. And knowing the rich and higher middle classes will never voluntarily give up their comfort, we necessarily have to admit techno-fixes will be needed.

Finally, to turn back directly to the population question, there is one argument I want to mention extensively and which comes from Ian Low in the debate on Great Transition:

The dynamic between population and climate control action plays out on both social and individual levels. Consider a recent study on the amount of CO2 emissions that could be reduced by various actions in the affluent world. Among the choices found to have most impact were living without a car (saving 2.4 tonnes of CO2 a year) and adopting a vegetarian diet (saving 0.8 tonnes a year). Long flights produce significant emissions, with a return transatlantic flight between North America and Europe releasing about 1.6 tonnes of CO2. But the savings that could be achieved by these sorts of actions were dwarfed by the potential impact of having fewer children. The calculation recognized that a child will not just be a consumer for their lifetime but probably in turn have children who will eventually have children of their own, and so on for future generations. By adding up the lifetime emissions of each child and their potential descendants, then dividing that total by the expected lifespan of the parents, with each parent assumed responsible for 50% of the child’s emissions, 25% of each grandchild, and so on, the remarkable conclusion was that having one less child would save the equivalent of 58.6 tonnes of CO2 each year of the parent’s remaining life. By this calculation, having one fewer child saves each parent more than 20 times as much as living without a car, or about 70 times as much as eliminating meat from the diet.1

So maybe, yes, we have to consider family planning in a democratic and participatory way. In this debate, there are many good arguments to consider regarding this point. However, some voices claim it would open the way to eco-fascism, it is a recipe for inaction and will all too easily evolve towards population control and feed into the ‘replacement theory’, against people of color and the poor people. It can become a genocidal plot against development. It can be an obstacle to radical consciousness. All this is certainly true, but what if democratic concern for population growth is only one element in a mix of measures. These arguments are to be taken very seriously. But can we not trust our democratic mechanisms to thwart them?

After all, it is obvious that more people mean more consumption. And living longer means polluting longer. Real de-growth will mean less for everyone, while all people have equal rights to a life in dignity. It means we will need much more energy, to mention just this one important element. It is the current inequality that makes it impossible.

What is undisputable is that environmental issues are re-generation or re-production issues, and that is why we have to look at the complete picture and not single out just one issue. Population growth can be problematic, but it is not necessarily the driving force of climate change. The real problem is income and wealth inequality.

Maybe we just underestimate the social change that will be needed for solving the climate question. Population growth will necessarily be a part of the issues to be tackled. And once again, social policies can be of great help.


1 Seth Wynes and Kimberly Nicholas, The Climate Mitigation Gap: Education and Government Recommendations Miss the Most Effective Individual Actions Environmental Research Letters 12 (2017): 074024, for the emissions impact of procreation, the study uses the findings of Paul Murtaugh and Michael Schlax, “Reproduction and the Carbon Legacies of Individuals,” Global Environmental Change 19, no. 1 (2009): 14–20.