Demography. The notorious “taboo” subject that we hear about daily. We would be too much on Earth for some people, and there would be an urgent need to find solutions to remedy this. To answer a subject as complicated as it is complex, we need time.

After 3 years working on demography and ecological issues, Emmanuel Pont releases his first book Faut-il arrêter de faire des enfants pour sauver la planète ? published by Editions Payot. We already discussed in 2020 about the subject in a first interview, but let’s use the opportunity of the book’s release to discuss about carbon footprint, politics, philosophy and ethics.

We often hear the name of Malthus to talk about the demographic subject, or rather the overpopulation. But let’s remember that philosophers were already talking about it 2000 years ago…

Indeed, humanity never stopped wondering about population and the environment. However, it was in a more limited sense than today, concerning mainly the resources such as food or wood. For example, Plato imagines an ideal city of 5040 citizens with control mechanisms to guarantee stability (women and slaves do not count …).

Malthus is part of this history and makes a stand against the debates of his time, against progressive thinkers and the Revolution spirit. His great innovation is a political reflection : if the population is limited by the food available, then the poor are, by definition, always at the limits of survival. What he presents as a “natural law” is specially the result of an unequal society, before demographic transition.

One quote in your book especially struck me : it’s the one said by Hervé Le Bras talking about Alfred Sauvy, saying that he was “a good demographer, but not a good prophet”. We finally learn that demographers have historically been very bad at anticipating major changes.

Sauvy in 1932 couldn’t, indeed, foresee World War II, the baby boom or the future migration policy and actually nobody could. Demographers are in the business of calculating demographic trends, they have no more crystal ball than you or I. Even the UN projections of 20 years ago, widely overestimated the speed of the demographic transition in Africa, and the opposite in Asia.

How much confidence can we place in these UN projections that are often mentionned as references?

It depends on the deadline. In the short term, there is not so much uncertainty, but the further we look, the more the world’s evolution has the potential to make the figures diverging. The UN projections reach a plateau around 11 billions in 2100, other demographers estimate a population of 9 billions at this date, with a peak much earlier.

The same limitations exist with the “current policies” climate trajectories. If one thing is certain, it is that these policies will change. These results are interesting for providing reasonable orders of magnitude and identifying important factors, but caution is needed in interpreting them. This is especially the case for countries where it seems to be impossible for the population to increase so much, especially in the Sahel.

“Save the planet” is written in the title of the book. Is it really the future of the planet under discussion ?

Obviously, the planet as a geological object is safe. But this naive question is an opportunity to wonder exactly what we are talking about and what we should want as an ecologically sustainable world. We’re used to think in terms of clear and quantified goals related to climate, but the answer is much more complex when we consider the whole ecological crisis. What’s the place of humanity among “nature” ? Some very different visions exist.

There is a shocking figure in your book that should put an end to some debates : countries with a high birth rate are only responsible for 3.5% of the world’s CO2 emissions, whereas they’re home to 20% of the world population.

If the debates could be closed with figures… Yes, we have known for a long time that the emissions are very unbalanced, and that this gap is not really reducing. This is particularly striking when we compare per person, in this case we can reach ratios of 1 to 100 … and particularly unfair because these are also the most fragile countries in front of global warming. It remains unbalanced, but a little less when you also count methane or calculate footprints for other ecological issues beyond climate. This difference remains mainly a wealth-related one :

What do you think about the Financial Times that headlines “Global warming is less becoming a battle between nations than between rich and poor” ?

It is very interesting that the “elites’ newspaper” recognizes the importance of the subject of inequalities in relation to global warming, both between countries and within countries. “World population” or “the average frenchman” are very regularly invoked to hide these huge inequalities, by mixing in the same figure very different situations. I like this expression : “when Bill Gates enters a bar, on average all customers are billionairs”.

Is there a maximum number of inhabitants on Earth? And in which living conditions ?

Indeed, it depends especially on what is our vision of a sustainable world and on the way they live, for which there is an important margin of degrowth. Concepts such as carrying capacity, which even in biology has a limited scope, can’t be applied in a crude way. And in fact, this is the idea behind all the disaster scenarios of billions of deaths due to global warming !

It is also very difficult to count, we can’t really use indicators like the ecological footprint, which only includes the climate and the production of natural environments, and fully depends on our lifestyle.

A hard limit still remains : food. Feeding 10 billions of people in 2050 in an ecological way is entirely possible but this will require major changes in agricultural practices and consumption. In particular, two subjects significantly overwhelm the others : meat and wastage. Hunger (2 billions malnourished people) is a question of distribution, we already have more than enough to feed everyone on Earth… it is just more profitable to give to our livestock or to our cars than to sell to the poor of the world.

What can we answer to Avengers fans who say that to address climate change, you need to summon Thanos and reduce the population?

There is a tendency to intuitively consider that if humanity were twice less numerous than today, it would pollute twice as little. This reasoning “all things being equal” is however very doubtful, one can easily pollute twice as much with a very similar standard of living. This can be seen, for example, in the difference between United States and Europe. It would also be an opportunity to keep waiting to act, and anyway for the climate emitting as much but later only postpones the problem.

I simulated the strict one-child system (worse than in China) applied in France: it would take until 2100 for the population to be divided by 2 ! The effect on cumulative emissions, that determines global warming, would be even more limited. Considering our pace of reduction in emissions per capita, they would only drop by between 3% and 11% in 2100. That’s really not much for an extremely coercive measure. I find it unbelievable how many mainstream movies, like Avengers, suggest that the environment is primarily a population issue.

You mention deep ecology but you don’t seem to take up its vision of the “biodiversity dilemma”, can you explain?

Yes, we are back to the debate on the vision of a sustainable world. It has to do in particular with biodiversity, which is very difficult to measure and that has no indisputable target. Population increase is indeed a factor related to biodiversity deterioration, but it’s once again “all things being equal”. When we delve into the world of research on the subject, we discover the huge variety of ways of living and relationship with nature, as well as an infinite number of possible (often local) changes to reduce our footprint.

On a global scale, making humanity vegetarian would free up three quarters of the land occupied by humanity. It is extremely effective in terms of demographic leverage. Therefore, I consider that there are enough possibilities to reach a reasonable version of a sustainable world, but of course this goal can be placed far enough away to consider that we are anyway too numerous.

Even if the demographic lever is not very effective and raises many ethical problems, should we not “do everything” ?

It could be if it was essential to reduce the population to achieve a sustainable world. But it is not, there are many others paths, so demographic measures must be carefully evaluated without forgetting their limits.

We must also consider political issues : not only the feasibility, which seems low, but also implications in terms of worldview, of framing the debate. Population control has always been a tool of authoritarian regimes and corresponds to an authoritative perspective, in which a higher authority decides who has the right to exist. Rather, it does not question any of the political and economic mechanisms that block change today, but is explicitly invoked to defend the status quo : if “we” (the others) were less numerous, we could continue polluting in peace.

Having one child would be equal to emit 2 tons of CO2eq/year more, or about 4% per couple. Could you explain how such a conclusion can be reached ?

There are different methods to estimate the emissions associated with a child, hence the variety in these figures. They are low because children require few consumer goods. These come however from the family budget, which would otherwise have been spent in another way.

This is one of the reasons why the “carbon footprint” related to having a child is very low, contrary to the absurd figures that may be circulating (which have been strongly moderated by their authors). By adapting this distribution for France and by reducing emissions at the rate needed to limit global warming to 1.5°C, we’re getting to the much more modest result of one ton per year for a child.

Ethics can be found everywhere in your book. Do having a child in the 21^st century become a personal ethical question ? There is a very interesting chapter explaining why choosing to have a child is not just a personal choice… It is surprising !

This dilemma is clearly seen in the definition of reproductive rights, which are fundamental rights but not absolute ones either. We can both consider this freedom to be desirable, while recognizing that having a child means imposing it on society. Thus, it is not easy to separate entirely the societal issue from that of individual choice, and this will depend on the orders of magnitude. If having a child was the worst thing for the environment, it would be debatable. Since these figures are roughly overestimated, I consider that the ecological issue is not a good reason to impinge on reproductive freedom.

Parents are rarely asked to justify having children. However, people who don’t have children still have to justify themselves. Are mentalities changing about this choice, in France and in the world ?

This is slowly changing according to experts in the field, but there is no figures to confirm. It is its very opposite that seems to become more popular, having to justify the ecological weight of its children ! Writing my book, I heard a number of “I have three kids… I know, I’m sorry, it’s not green”. The great majority of people that expressed themselves on this subject was women, as they are the ones being under cultural pressure to have children.

Should we be afraid of giving birth to a child in our uncertain world ?

This is the other important question about personal choice : the fear of the children will be facing a horrible future. Considering the uncertainty about the ecological crisis, it is only natural that we oscillate between extreme positions, between catastrophism and reassurance. How to find a “happy medium” ? There already are and will be disasters, even if most of them are not written, and will depend on our mitigation and adaptation choices. There are also many “solutions”, although none are simple or easy. I have no absolute answer to this question, which will depend on individual circumstances. Among the interesting examples, we can mention Pablo Servigne who has chosen to have children while being convinced of the risk of collapse. According to him, forgo having children would have mean to give up all hope.

On such a sensitive subject, how can one not be counterproductive ?

By taking time to present the complexity of the issue, without hiding it behind numbers or too speedy judgments. By not forgetting the ethical and political issues, as opposed to a “video game” posture where one would only have to apply the right measures. By not getting ‘debunking’ a front row seat, but by answering the questions that people really have.

With such a complex and multidisciplinary subject, you will unfortunately not always have the time to elaborate, to nuance. What do you answer to someone who wants to know in two minutes if having a child is good or bad for the “planet” ?

My answer is that it will depend on how he lives, and his impact on the world, which goes much further than his carbon footprint as a consumer. About this, there is no fatality : there are many ways, on an individual or collective scale, to make it low and compatible with a sustainable world.