Just population policies for an overpopulated world

After three decades of neglect, more environmentalists are waking back up to the need to limit human numbers. But like Rip Van Winkle, we find that the world changed while we were asleep. There are now billions more people, consuming more than ever, while our world has grown warmer, tamer, and more polluted. A new article in The Ecological Citizen discusses what just population policies might look like in an overpopulated world.

by Philip Cafaro

Like other sustainability advocates promoting reforms that run counter to mainstream economic boosterism, population advocates have learned to carefully police our language and temper our proposals. Given how far our societies are from sustainability, just slowing down their enthusiastic charge in the wrong direction can look like a reasonable goal. For instance, “population stabilization” sounds less threatening to our fellow citizens than “population reduction,” so that’s what we often end up arguing for. But as Karin Kuhlemann observes, “that a population’s size is stable in no way entails sustainability. It may be sustainable, or it may be far too large.”

There’s the problem. Globally, current human numbers appear nowhere near compatible with long-term human wellbeing and the flourishing of other species. In their article “Sustainable welfare and optimum population size,” Theodore Lianos and Anastasia Pseiridis calculated that the world could safely accommodate 3.1 billion people living on an average annual income of $9000 per person, an amount deemed sufficient for a satisfactory life. They then calculated sustainable populations for the world’s 52 most populous nations, on the premise that each country was entitled to a share of the sustainable global population equal to its share of global cropland. Graph 1 below shows the difference between recent, future, and sustainable populations for the world’s five most populous countries based on these stipulations.

Graph 1. Population and overpopulation in the world’s five most populous countries. Data in first two columns from Lianos and Pseiridis (2016), last column from United Nations (2019).

These sustainable national population estimates assume a willingness to limit or reduce average annual income to $9000; at higher average incomes, the sustainable population decreases proportionally. Of course, income is only a crude measure of our use of natural resources and generation of wastes, and many other things besides the availability of agricultural land factor into sustainability. Still, these rough calculations give some idea of the amount of population decrease these five countries would need to achieve sustainability.

Clearly that amount would be immense. China would have to cut its population by nearly 1.15 billion people to reach sustainability: from 1.4 billion today to approximately 250 million. India would need to reduce its population by nearly as much, down from 1.4 billion today to about 340 million. At first glance, America looks in better shape, but only if we ignore the need to drastically cut income and consumption to sustain 325 million people. Americans’ average annual household income in 2020 was around six times greater than $9000, so unless we were willing to cut our incomes substantially, a sustainable U.S. population would need to be a small fraction of our current numbers.

Looking at the UN’s projected populations for 2100, none of these five countries are anywhere close to achieving a sustainable population under current demographic and economic trends and policies. Nor are most other nations, whether overdeveloped or underdeveloped. This is shown, for example, by Lianos and Pseiridis’ calculations for sustainable populations for the seven most populous European nations, shown in graph 2 below.

Graph 2. Population and overpopulation in Europe’s seven most populous countries. Data in first two columns from Lianos and Pseiridis (2016), last column from United Nations (2019).

Leaving aside Russia as a continent-sized outlier, the six other most populous European countries would all have to cut their populations substantially to achieve sustainability: France by 40 per cent, Italy by 66 per cent, Germany by 70 per cent, the United Kingdom by a whopping 81 per cent – down from 63 million to 12 million people. All this, remember, with the stipulation of an average annual income of $9000. With the extra income that most Europeans probably would want to retain, sustainable population sizes decrease proportionally.

Developing nations, meanwhile, face demands for more consumption by the poor, rising consumption by a burgeoning middle class, and the same excessive consumption by the wealthy seen in the developed world. Here, too, sustainability demands decreased human numbers, to free up ecological space for the poor to increase their consumption. Instead, many developing nations are moving rapidly in the opposite direction, as shown in calculations for sustainable populations for the six most populous sub-Saharan nations (graph 3 below).

Graph 3. Population and overpopulation in sub-Saharan Africa’s six most populous countries. Data in first two columns from Lianos and Pseiridis (2016), last column from United Nations (2019).

According to Lianos and Pseiridis’ calculations, Nigeria would need to decrease its population of 206 million to 38% its current size, 79 million, to achieve a sustainable population at an average annual income of $9000. Instead, it is on track to increase more than 250% by 2100, to 733 million people. Ethiopia’s current population of 115 million would need to shrink to 31 million, 27% its current size, to achieve a sustainable population. Instead, it’s currently projected to increase by 155% to nearly 300 million. And so it goes throughout the region. Comparing these three graphs shows us that for all their differences, richer and poorer nations today share a key characteristic: they are both massively overpopulated relative to the income and consumption they engage in or aspire to.


Population policies for an overpopulated world

Around the world today, overpopulation contributes significantly to unemployment, malnourishment, crowding, poverty, disease, and other harms afflicting hundreds of millions of people. In this century, it threatens billions with such suffering. Overpopulation has also contributed to massive biodiversity loss over the past century and threatens to extinguish millions of species if not reined in. Arguably these facts don’t merely justify stringent efforts to reduce human numbers as quickly as humanely possible. They require them, as a matter of justice between current and future generations, and between people and other species.

That’s the premise of a new publication I recently published in The Ecological Citizen as part of their special issue on overpopulation. “Just population policies for an overpopulated world” tries to strike the proper balance between protecting reproductive rights and promoting reproductive responsibility, and between human interests and the well-being of Earth’s many other life-forms. In it, I claim that overpopulation justifies a new ethical imperative:

  • would-be parents should restrict themselves to one child

Larger families are socially irresponsible at this point in history, whether in rich societies or poor ones. There simply isn’t room for them. The paper further argues that urgent environmental threats also justify stringent public policies designed to rapidly, yet humanely, decrease national populations. In particular, it maintains that national governments should:

  • guarantee their citizens universal, affordable access to family planning services, modern contraception, and abortion on demand.
  • encourage their citizens to have only one child and discourage them from having more: through widespread information-sharing, tax and benefits policies, and direct advocacy to change patriarchal norms.
  • strictly limit immigration, as part of comprehensive efforts to reduce their populations to sustainable levels as quickly as possible.

Together, I claim, such measures can reduce national populations rapidly, yet fairly. This in turn could make possible genuinely sustainable societies and allow people to share the landscape generously with other species.

Of course, I do not argue that societies should average only one child per couple forever. That would lead to permanently decreasing populations and, eventually, human extinction. In time, once they reach a sustainable population size, societies can transition back toward averaging two children per family. But that time is several generations in the future. For now, we need to average one-child families—on pain of potential ecological disaster.

Many people will disagree with the need for prescriptive policy measures to reduce human numbers, which, to be clear, is my own position, not necessarily TOP’s. But before dismissing such proposals, we need to be open and honest about what is at stake and whether unprompted voluntary restraint can be sufficiently effective. We invite you to read “Just population policies” and express your views by posting comments below.


Other articles in The Ecological Citizen’s special issue on overpopulation include:

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31 thoughts on “Just population policies for an overpopulated world

  1. Excellent article, all, except the effort NOT to scare people. Population density stress is killing us NOW! And the ONLY solution is voluntary one-child families in order to reduce human populations to a barely sustainable 3B by 2,100. Stress R Us

      1. The truth often is “scary”. Maybe even always “scary”. I used to react badly when I was younger, to my parents and others who were fans of Dr Paul Ehrlich and other overpopulation “prophets of doom”. But of course now I can see they were all right – and slowly the same thing will happen to nearly everyone who is in denial about why everything is collapsing. People like you are a really major aid to making the truth more palatable – not by fudging it, but by presenting it in a cool, academic manner and collating the work of obscure researchers.

  2. I am seeing overpopulation everywhere.

    Watching the tragedy unfolding at the border between Poland and Belarus, I think: this is what actually reducing immigration looks like.
    Apparently, repatriation (the only humane solution) is available for these people, but they refuse it. They don’t want to go back to their countries as they have no jobs or opportunities there – yet no one makes the connection with them having overpopulated, through the sum of millions of individual choices, their own lands.

    I just watched the Oscar-winning film Parasite. Aside from the obvious inequality theme, it gives a pretty-to-look-at, horrendous-to-contemplate picture of a grossly overpopulated country. Its population density is over triple that of China. I am fascinated by South Korea – its immensely popular cultural exports appear as either a parody of or a warning about Western consumerism and cutthroat capitalism. Its young people are literally refusing to reproduce. Their TFR is less than one. Men and women are at war with each other.

    Today I was in the hospital with an old woman who was going on about her grandchildren. It’s completely ok here for strangers to ask you about when you’re having kids, and when I told her I don’t want them, and why, she was horrified. Overpopulation, resource exploitation, environmental disaster, global inequality… it was all new to her.
    “How do you know all this?”, she asked.
    Then, completely unconvinced, she said: “Shame on you.”

    1. Do you think part of the solution here is “young people refusing to reproduce”? I worry that means “young people who have a social conscience and care about the environment” not reproducing, and those who don’t care going ahead and having as many children as they want, or blunder into.

      1. Unfortunately, I think that a case could be made (though I’m not sure this is always true) for people responding more to economic circumstances and social pressures than to their own principles.
        Here I was speaking about South Korea. I’ve never been there, but from what I’ve read the extremely low fertility is more about life being unaffordable, extreme crowding and harsh gender inequalities, rather than concern about the environment. I have no idea about environmental sensibilities there, but their cultural exports sure promote almost surreal levels of consumerism.

        (Interestingly, while Western pop stars become famous through their antics as much as their work, K-pop stars are expected to be or appear celibate, and punished severely otherwise. From what I’ve read Japan has seen a growth in various types of sexless or even virtual relationships. I think these are all reactions to an environment, in the broader sense, that is not conducive to human reproduction. Urbanization might be a factor among others)

      2. I completely understand your idea that to leave reproduction to those of us who don’t spare a thought about over-population (or the environment) would be counterproductive. However, I’m cynical enough to suggest that we humans are just terminally selfish. We seem to be driven by ‘personal get-out clause’ like: “it will be ok if only I do it” Unfortunately there are 8 billion of us ‘Is’ and each of us is consuming, throwing away, and reproducing our selfish way towards extinction.

    2. Polish – Belarusian border case does not mean that reducing immigration must look like this. This is a scenario created by two authoritarian regimes. Our government uses this situation as political fuel to cover their scandals, corruption, conflicts with EU, rising 4th wave of coronavirus, inflation ca. 7%, women dying because of near-total abortion ban and many other issues. They can play with card of external threat to win support in a racist society and distract people from thei incompetence. Sorry, but Poland is a country well-off enough to relocate these people to refugee settlements and give them shelter for this couple of days it would take to decide if those people are refugees or not. After several flights back to home countries this migration track would be abandoned.

      1. Lukasz – in principe, I agree. I wish this would be taken care of differently. Yet, unfortunately, I don’t think it would be so easy.
        Those people do not want to be sent back home. You’d have to force them onto planes – what would *that* look like?
        They protest, threaten suicide. Courts or protestors stop the repatriation. The countries they come from refuse to take them back. Or they have themselves destroyed the documents, so you cannot know where to send them.

        Italy, my country, does what you suggest, takes people in to see whether they have the right to be considered refugees. Let me tell you what happens next. I’m not citing propaganda but things I have witnessed or been told by people who know first-hand.
        Those who can blatantly lie about their age, so that they can get “minor” protection status. Many then simply vanish. Overall, so many people apply for protection that the courts are overwhelmed. It takes months to process applications. When, as it often happens, protection is denied, some people have disappeared, others appeal. It goes on for years in this limbo. Other European countries promise they’ll take some, then don’t. Those who do not have the right to stay in Italy are still here, even when they commit crimes. A good number works, legally or not, in slave-lilke conditions. It keeps getting worse.
        And none of this serve as a deterrent. Every once in a while, incapable of solving the situation, the government simply legalizes those who are present illegally.
        So people keep coming.

        If Europe is letting Poland do this, is because nothing else is working.

  3. The interesting linkage between rise of incomes and falling fertility ust be studied more thoroughly. Should it appear, that such a linage exists, the challenge will be in decoupling those two phenomena. Because if we can only win smaller family sizes by rising incomes, the effect would be devastating. Some countries show, that such a decoupling is possible. Take Ukraine as example. The population is already falling (not mentioning emigration) while income level is relatively low.

    1. Yes yes, you are right to some extent – but in the end, you cannot decouple Finite Resources from either Population Numbers or Per Capita Consumption Leves.
      Thus if incomes rise and Total Fertility Rates fall (mainly due to the “liberation” of women puls infertility caused by pollution) – you still have a problem, as the article shows in the case of the USA.
      Most nations are on a similar path – one that will decrease births and increase incomes.
      But if this increases per capital Consumption (which it has in the USA) – you still have a huge problem, an even worse one possibly than Niger with average 6 babies per woman but very low incomes and very low consumption.
      Thus education of women + birth control is not the magic fix that it is claimed to be.
      It could even make things worse.
      The article could not make it clearer, that an average income of $9000 a year is the core foundation for any possible solution.

    2. I believe it is not rising incomes but the rising cost of having a child, coupled with availability of contraception – and both correlate with higher incomes, hence the confusion. Also that women have different aspirations beyond or instead of child-raising – this also occurs in more affluent societies. I know there’s a researcher that argues that the hope of higher standards of living actually increases the birth rate, but I cannot remember her name.

  4. There are many nuances. But broadly speaking, when women enter the paid workforce, fertility levels decline rapidly and remain at or below replacement rate. At least that has been the case throughout the developed world.

    Within the developed world, fertility rates average between 1 and 2 children per woman. Toward the high end in societies where women can have families and a career, with generous economic support from the state (Nordic countries, France), toward the low end in countries where women don’t have such support and have to choose between the two (southern Europe, Korea, Japan). There may also be cases where other factors depress fertility even further: Italy is around 1.4 TFR, but Korea is around 1 (or even lower?) and as gaiabaracetti suggests maybe that is because of toxic relations between the sexes, or overcrowding, or a sense of impending doom …

    1. I think that in societies (Italy mostly too, SK, Japan, and China also comes to mind from what I’ve read) where men are not expected to help with housework and childcare, but women have entered the workforce en masse, the sacrifice for women who have children in terms of career and time for themselves is even greater, hence the slightly lower fertility.
      I think that in Northern Europe both the state and men help with children, whereas in Southern Europe it’s more the extended family, if you happen to have one living close to you. Or paid help, mostly immigrant or poor, and female. I’ve always thought that the “liberation” of women in the West has happened mostly at the expense of other women, not of men.
      Anyways, since many people in these countries are choosing to have no children at all for other reasons, I think the main problems right now in terms of population are migration and high-fertility countries.

  5. It doesn’t need to be through coercive means. If you look at many countries that struggled with overpopulation for example Singapore you can set up policies to encourage two or fewer children as a matter of social responsibility: https://en.wikipedia.org/wiki/Population_planning_in_Singapore

    Sadly this usually happens after the density has gotten too great, which means you’re already starting 30 years too late. But good luck getting societies to be more proactive than that.

    1. As the Covid pandemic revealed starkly, Singapore is servanted by a great mass of foreign workers who are virtual slaves. In any case, it is not a good example for population De-Growth. So societies need to be a great deal more pro-active than Singapore – as you rightly point out. Also, what is the average income in Singapore (for full citizens, discounting migrant workers)? I bet it is a lot more than $9000 p.a.
      Comments are neatly avoiding the core point of this article, and of the research it is reporting. No-one wants average national incomes to be $9000 a year, clearly. So there is no hope of a solution.
      Leaving out the thorny “average income” aspect, this is from Statista on demographics:
      “With an urban population of around 5.69 million people in 2020 and a land area of approximately 720 square kilometers, Singapore was the third most densely populated territory in the world in 2020. The population of Singapore is estimated to grow to 6.52 million people in 2035.”
      Worldometer puts the population at 5.9 milllion by 2021, continuing the steady and quite steep rise from 1 million in 1950. The projection for 2035 is 6.38 million (i.e. the rise is slowing, but still a rise).
      Macrotrends puts the whole population at 8.2 million in 2021, moving Singapore up to second place after Macao in the population density tables. I do not understand the difference of over 2 million people – but I suspect Macrotrends are counting (estimated) non-citizen servants from the Philippines etc. These are difficult to count, as Singapore is secretive about them, and they have no official existence. Most developed nations have huge numbers of “undocumented” migrants doing the menial jobs. In a pandemic,they surface to get their jabs – as the hidden Chinese labourers in the UK did when they were offered an amnesty for vaccination purposes. Then they retreat to their underworld.
      Their incomes could drag the average income down quite a bit – so perhaps they should not be counted or estimated, if any Nation does care to try and work towards an average income of $9000 a year? It should be an average of documented, minimum wage and upwards, incomes.

      1. 9000 isn’t so bad if you don’t have rent and you work less hours outside the house and get to do / make more of the stuff you need, instead of buying it or paying people to do it for you.

  6. As a matter of fact you propose a surplus of deaths over births, but your unique focus is on birth control. There is a paradox in our intentions to reduce population and our efforts to increase life expectancy and to counter hunger by food aid in regions that cannot feed their population, as well as in the western habit to intervene in armed conflicts and in situations of genocide and pandemics. But “even if the human collective were to pull as hard as possible on the total fertility policy lever […], the result would be ineffective in mitigating the immediately looming global sustainability crises (including anthropogenic climate disruption), for which we need to have major solutions well under way by 2050 and essentially solved by 2100.” [Bradshaw and Brook, 2014]

    Time for resignation?

    1. They are not just focusing on birth control if I understand correctly, but also on reducing consumption. Difficult, but still better than letting people starve or die of preventable diseases.

    2. Great quote from Bradshaw and Brook – thank you.
      Certainly, if everyone continues to think having fewer babies is the answer, resignation to Fate is the only option.
      Well not the only one – but the best one.

      1. I expressed that very badly indeed. What I meant was, having fewer babies is essential – but is not ALL we need to do. As Lianos and Pseiridis calculate, global population needs to go down to about 3 billion maximum – and stay there. But AT THE SAME TIME, all nations will need to live on an average of $9000 a year (most earning less, some earning more, some a lot more). If the second thing does not happen, then the population will have to drop a lot lower than 3 billion.

  7. Whilst living in a remote area of Ethiopia I was approached by a poor woman to provide her with the contraceptive pill. An educated Ethiopian wonan pointed out that she would have been prevented from contraception by her husband.

    My belief had always been contraceptive practice was a function of public health provision and education. It appears a big stumbling block is the poor male.

    1. I’ve read of women in Africa being beaten by their husbands for getting contraception without their consent. Which is why some ngos are now talking to the men as well.
      In pretty much every case I have heard of or read about of different desired number of children, the man’s is always higher than the woman’s.
      You can’t put a man through pregnancy, but get him to leave his job for months before and after eveyr birth, change diapers, feed at all hours, help with homework and the like, and desired number of children drops like a rock.

  8. Excellent summary of the challenges facing us Phil. I live in South Africa, and the graph for the DRC and Nigeria terrify me. Many millions will head south to South Africa and we do not have the border control systems to prevent it. We already have many millions of migrants from Zimbabwe, Malawi etc looking for a better life.

    1. Yes, mass migration is an issue from one end of the world to another. We need to reinforce the message that this is a function of global overpopulation, evidence that populations need to decline throughout the world. As opposed to the lesson the business press and their allies throughout the media are drawing: that it is evidence of the need to move labor from where it is surplus to where it is lacking.

      1. Labour *appears* to be lacking because people want to retire early / don’t want to accept certain working conditions nor fight for better ones / are spoiled, basically. They think that by withdrawing from certain professions or by retiring they are avoiding exploitation, whereas what’s actually happening is that they are letting other, poor, desperate, expendable people be exploited instead -mostly, but not exclusively, immigrants. Then those immigrants’ kids grow up, they acquire the same expectations as most westerners (or Gulf Arabs or whatever, depending on where this happens), you need to import more immigrants to do the useful jobs for low pay, and so on and so forth – until it crashes.
        The bad employers love it – they find ways to exploit this pool of people until they get caught. The good ones struggle because labour is actually expensive but in a global economy you still have to compete with places where it isn’t.

        I’ve been trying to hire someone (legal, good conditions) for six months now. Still haven’t – yet I am surrounded by people who do not work, do not do anything productive, but would be perfectly capable of working. Everyone is advising me on some suitable, subsidised nationality to look for: “Get some Indians, they love cows! Get some newly-arrived Pakistanis/Africans and the state to pay for it!” (it actually does – you can get free labour because they need to be “integrated”). It’s disgusting on so many levels.

        Italy has a population of about 60 million, out of which just slightly over a third, about 23 million, has formal employment. They are supporting the rest.
        Importing workers in such a situation is insane.

        Sorry for commenting so much.

  9. I suggest TOP looks at decisions at EU of the overpopulation problem, specially reducing birth rate. I observed the problem at the Glasgow climate conference. The idea of UN is that each country submits their intentions relevant to future climate (NDC). EU has issued a NDC (19 pages) https://www4.unfccc.int/sites/ndcstaging/PublishedDocuments/Sweden%20First/EU_NDC_Submission_December%202020.pdf I searched and found that the following words are not included: overpopulation, population, child, girl, birth, sexual, education. No intention of reducing the number of babies in EU. Please look deeper into that!

    1. I think it’s almost impossible to make European birth rates lower than they are now. Europe’s problem is migration from high-fertility countries.

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