Ethical perspectives on population and the Sustainable Development Goals

On the 25th of September, two core members of The Overpopulation Project attended the “Ethical perspectives on population and the sustainable development goals” workshop organized by the Institute for Future Studies in Stockholm, Sweden. At the one-day workshop, we gained valuable insight into how philosophers and political scientists frame the relationship between human population growth and climate change.

By The Overpopulation Project

Last week, several team members of the Climate Ethics and Future Generations project gathered with the objective of discussing population in the context of the Sustainable Development Goals (SDGs). The organizers Eric Brandstedt, Olle Torpman and Henrik Andersson noted that the SDG’s do not include population growth or population size, and were curious about the role of population in the broader SDG framework. The purpose of the planning workshop was to gather experts to evaluate the role of population in the SDGs, brainstorm new ideas, and identify potential collaborators for their future project. Although the aim was to uncover the relevance and significance of population to the SDGs, the presentations and discussions were mostly limited to the relevance and significance of population to climate change mitigation, a significant limitation.


The first speaker, Kalle Grill (philosopher from Umeå University) explained four moral differences between procreation and overconsumption, and discussed important distinctions to make when examining policies to limit (luxury) consumption and/or procreation. He argued that procreation has both higher instrumental and non-instrumental value than procreation, and that the environmental harms caused by children also depends on their independent choices and decisions, and hence should not be fully assigned to their parents. He also argued that as an environmental solution, the effects of limiting procreation are delayed compared to changes in consumption, but did not discuss practical conclusions or policy recommendations that might follow from the moral distinctions he draws.

Simon Caney (political scientist at University of Warwick) also stayed in the abstract theoretical plane while outlining his liberal approach to ecological sustainability. Although his presentation was limited to climate disruption, in theory his Ecological Liberalism framework could ensure complete ecological sustainability in a just and politically legitimate way, if properly worked out. The framework is built around an environmental impact cap that is fairly distributed among individuals. How individuals choose to “spend” their environmental allowance – via procreation or varying means of consumption – is up to them. Individuals can freely choose how to live within their fair shares, but all choices that affect the environment are charged to the individual’s allotted environmental allowance. Structural factors that influence one’s impact on the environment (e.g. infrastructure, public transit systems, waste systems) would be decided democratically at the lowest collective level possible.

In Caney’s framework, having children would not bear a stigma or be special compared to consumption acts that impact the environment. Ecological liberalism acknowledges limits and the role of population as it interacts with the other factors in the IPAT formula, but does not want to single out “P” from the equation. Caney argues that it is better to have campaigns explaining the merits of sustainable living, which would make obvious the importance of responsible reproductive choices. While massively relying on technological innovation, “T”, the approach does not consider technology alone sufficient. It is easy to agree with many of the features in this approach, as well its virtues of fairness and democratic self-government, but it is difficult to imagine it in practice.

The speaker who raised the most questions in our minds was Hilary Greaves (philosopher, Oxford University), who discussed contrarian perspectives on the population debate. She concluded that it is not obvious that smaller future human populations would be better than larger populations in terms of climate change mitigation and resource depletion. Instead, Greaves emphasized the benefits of a larger, growing population. She argued that since peak warming is determined by cumulative emissions, not by emission rates, the former must become net zero as soon as possible, achievable only through technological innovation. Since smaller populations (or slower population growth) only reduce the emission rate, she does not consider it helpful, even though slower emission rates allow more time for innovation.

According to Greaves, population growth fosters innovation, because in theory, more people will drive more technological progress. This is a common line of thought, but overlooks the untapped potential of billions of people who already exist, and also overlooks the fact that technological research globally is already strongly increasing. Currently, the fastest population growth occurs in parts of the world that lack quality education and opportunities, and this trend is likely to continue.  Continued population growth in these regions will likely result in further untapped potential rather than world-saving inventions. Thus, even if we are thinking in techno-optimist terms, ensuring universal access to quality education would do more to untap the innovative potential of people who currently lack those opportunities than limitless population growth. In any case, the IPCC identifies population growth as one of the two main drivers of climate change, and notes that continued population growth will further intensify climate impacts by undermining societies’ abilities to adapt. Greaves’ view ignores these points, as well as the contribution of population growth to freshwater shortage, logging of tropical forests, and the extinction of species.

Figure 1. Climate change hits hardest at the countries experiencing the most rapid population growth. Population growth clearly makes adaptation harder and the impacts of climate change worse, while there is no evidence that it accelerates success in climate research (Oxfam, Gemma McSherry)

A similarly questionable idea is the need for temporary resource overshoot to stimulate innovation,  based on Boserup’s theory that “necessity is the mother of invention.” According to Boserup and Greaves, we would not have achieved advanced societies without past population pressure forcing innovation, and we need future population pressure to further advance societies. This then begs the question, how “advanced” do we want to be, and what are the trade-offs? The idea that technological innovation relies on population pressure left us unconvinced: larger future populations or faster population growth would hardly be good for future human and environmental well being.

Kimberly Nicholas (environmental scientist, Lund University), was concerned about unsustainability for the sake of both humans and non-human species. She illustrated the gravity and urgency of climate change by showing the latest data projecting coral reef death and biodiversity loss. She highlighted that population and economic growth continue to be the main drivers of rising carbon emissions. Despite this, according to Nicholas, limiting population growth today and in the near future is irrelevant for solving the climate problem. This is because we have only 8 or 22 years to limit global warming to 1.5° or 2°, respectively, and most impacts of fertility reductions would occur beyond these time limits; thus, the positive impacts of reducing population growth are too long-term. Although the size and growth of populations is relevant in climate adaptation, it is not as relevant because it does not help solve the problem, and the people who must solve the problem are alive today. The solution demands that we stop burning fossil fuels as soon as possible.

Carbon countdown

Nicholas’ solution to climate disruption is well known. But so far, insufficient action has been taken. Therefore, long-term investment in family planning programs is a desirable complement to other efforts, in our view.

Nicholas also reviewed how the ‘population-climate’ connection is talked about in the media, concluding that it is a difficult, divisive topic to discuss that requires courage, or at least a hard head. The Overpopulation Project certainly agree with this conclusion, based on our experiences.

Dean Spears (economic demographer and development economist, University of Texas Austin), was the last speaker. He provided further evidence for the argument that fertility policies today are not very effective in mitigating climate change in the short term. If fertility dropped instantly to replacement fertility (2.1 children/ women), it would limit global warming only 0.5°, from 7.1° to 6.4°, compared to a business as usual scenario[1]. This is partly because even with instantaneous replacement fertility, the global population would still increase to about 9 billion due to population momentum. In addition, even if unintended pregnancies are reduced, Spears argued that there would be no significant effect on lifetime fertility outcomes, since achieved fertility is correlated with intended fertility. Thus, fertility policies need to focus on reducing intended fertility, which takes even longer.

Spears’ presentation thus continued a recurring theme of the meeting: that because greenhouse gas emissions need to be reduced very fast to avoid the worst of climate disruption, limiting population growth has little or no role to play in these efforts. However, this view ignores the fact that slower population growth has numerous benefits for individuals’, communities’ and countries’ adaptive capacity and resilience. It is also true that climate change, while important, is only one of many global environmental challenges facing humanity. Arguably, looking to the long term, population stabilization or reduction does have a role to play in overcoming these environmental challenges.

The organizers concluded in the media that there was a clear consensus among the speakers that restricting procreation is not an effective means of combating climate change, and that the benefits of reducing population growth are limited. However, they excluded the role of population in adaptation to climate impacts, and all non-climate change environmental challenges. Though we heard some contradictory and controversial ideas, The Overpopulation Project wishes them good luck in their research and is interested to see how it evolves in the future.


[1] Mark Budolfson and Dean Spears, “Population momentum, population ethics, and the prospects for fertility policy as climate mitigation policy” ; working paper (2019)

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15 thoughts on “Ethical perspectives on population and the Sustainable Development Goals

  1. What a depressing article. The reality of right-now has little to do with the often ill-considered “scholar-babble” that these sort of events bring. … One major problem that reoccurs is this: The idea that individuals have some sort of “right” to choose how they live. Our larger “society” created this terrible problem, by allowing (even creating) the fabric that permitted the current human population of individuals to exist. And so, collectively, we need to develop a solution.

    To do this, we first must shut down the idiots who say there is no problem; to not share a forum with them. Then we need to limit human births, by deciding to have a plan that each family, worldwide, will have no more than two children (or one, or zero, as each family chooses). I hope The Overpopulation Project can lead the way.

    1. Please understand: I do not mean the use of physical coercion to limit births. Rather, social promotion of the idea, and financial disincentives.

  2. In a number of rich countries, especially in western Europe, population growth is merely caused by immigration. People with lower carbon footprints move in and take over a life style with a much higher footprint, simply by adaptation to the new community.
    In the field of CO2-emissions population growth (especially in the Middle East and Africa) operates as a two-storey missile: first regional population explosions, then mass migration to other countries which are desperately trying to reduce their emissions.
    Human population reduction per se may not be a quick fix for climate change, immigration control is.

  3. The opinions of ethical experts reported in the latest blog (Ethical perspectives..) are so anthropocentric. These modern-day ethics academicians haven’t intellectually evolved as much as indigenous people did. I don’t know if I should laugh or cry.

  4. Since at least the 1980s, the “South” (underdeveloped) nations have been asking the rich world for aid specifically to reduce population growth. Patriarchal religions, indebted governments, and global business (the 3 main global institutions) have fought that as they all desire growth for revenue reasons. See excerpt from my 2000 paper given to The World Congress of the System Sciences:

    In 1989, as verified by The UN Population Fund, the following countries signed
    a statement urging early stabilization of human population. Austria,
    Bangladesh, Barbados, Bhutan, Botswana, Cape Verde, China, Columbia, Cyprus,
    Dominica, Dominican Republic, Egypt, Fiji, Grenada, Guinea-Bissau, Haiti,
    Iceland, India, Indonesia, Jamaica, Japan, Jordon, Kenya, Rep. of Korea,
    Liberia, Malta, Mauritius, Morocco, Nepal, Nigeria, Panama, Philippines,
    Rwanda, Senegal, Seychelles, Singapore, Sri Lanka, St. Kitts-Nevis, St. Lucia,
    St. Vincent & the Grenadines, Sudan, Thailand, Tunisia, Vanuatu, and Zimbabwe.
    Note the absence of most wealthy nations. It is ridiculous to claim that the
    rich are trying to coerce the poor nations to reduce population. In fact, they
    are not responding to the affirmed needs of the poor.

    The following countries are part of either the South Commission or Partners in
    Population and Development: Zimbabwe, Kenya, Mexico, Colombia, Thailand,
    Indonesia, Bangladesh, Morocco, Egypt, Tunisia, China, India, Pakistan,
    Uganda, Algeria, Argentina, Brazil, Cuba, Guyana, Ivory Ciast, Jamaica,
    Kuwait, Malaysia, Mozambique, Nigeria, Philippines, Senegal, Sri Lanka,
    Uruguay, Venezuela, Yugoslavia (former), and Western Samoa. The “Partners”
    share expertise with each other in reproductive health, appropriate
    technologies, and population policy. The Challenge to the South: Report of the
    South Commission, included this unequivocal statement:

    ” In the long run the problem of overpopulation of the countries of the South
    can be fully resolved only through their development. But action to contain
    the rise of population cannot be postponed.” (Nyerere, 1990)

    The full paper has been online for 19 years with zero rebuttals. It is currently here:

  5. I agree with Robert Fireovid’s criticism of the participants’ apparent anthropocentrism. I didn’t attend, and perhaps the full presentations gave more attention to other species’ well-being than this summary suggests. But if not, I think a purely anthropocentric ethical approach disqualifies their policy suggestions.

    On another topic: it appears to have been a recurring theme of the meeting that because greenhouse gas emissions need to be reduced very fast to avoid the worst of climate disruption, limiting population growth has little or no role to play in these efforts. Most published explorations of this topic have been much more upbeat about population activism’s potential to help mitigate climate change, including publications from the IPCC. This may have been in part because they have not indulged in wishful thinking about techno-fixes–which itself is just another manifestation of humanity’s self-infatuated anthropocentrism.

    Finally, it seems to me that climate disruption, while important, is only one of many global environmental challenges facing humanity. Arguably, looking to the long term, population stabilization or reduction has an important role to play in meeting all of them. And if part of our definition of a sustainable society is one that leaves sufficient room and resources for other species to thrive, then limiting human numbers has got to be part of the answer

  6. Although it would not reverse climate change, I would argue that the cheapest way to try and decrease the increase in co2 production is to make all contraception free world wide

  7. Nicholas argues that limiting population growth does not solve the problem of climate change, but she neglects to discuss the alternative: letting the population increase will exacerbate the problem even more. So it’s true that reducing population growth is not sufficient (in the short time), but it’s however necessary. Nicholas seems to conflate non-sufficient with non-necessary, which is a big mistake in logic. Very disappointing by someone who pretends to be an expert.

    1. A good point, which I hadn’t thought of. After all, whatever scenarios we run and whatever other policies are in place, sheer human numbers will remain a key determinant of GG emissions, at least for the next few decades and probably for even longer. “P” remains a variable in the Kaya identity. –P Cafaro

  8. Agreed birth rate reduction will not be in time to reduce emissions to a workable level, but all efforts to do so should move quickly forward. Obviously, reducing consumption would have a rather immediate effect. However, I am reminded of a comment by Dick Cheney when he said, “We cannot do anything about climate change because it will affect the economy. “ BY this he meant if we were to take down consumption, particularly of fossil fuels, the economy would fail. This, of course, is most likely true particularly if it was rapid, which it needs to be.
    I might note that the only time emissions have dropped (slightly) was in 2008 during the big turn down. The implication is clear that the only way to reduce emissions is to have the economy, as we know it, collapse. This deliberate attempt by practical economist/environmentalist would not be met with open arms. As an advocate of such an attempt, I would head for the hills and not the local bar. I does seem to me, that as long as the world gets an additional one million humans every 4.5 days, and economic growth is the uncontrolled mantra, there is little to no hope of mitigation. It probably is more about adaptations and options.
    The individuals at your conference, while articulate and thoughtful, are not pragmatists but just delusional dreamers who have allowed the agenda of their genes to substitute blind faith, and wishful thinking into complex thoughts unfounded on the harsh reality of what may be our fate of being a plague species.
    It might be more worthwhile to have a discussion on the effects of an increase of the death rate, say an additional 80 million every year, because the likelihood of that appears to be eminent. If the world economies should fail, say due to resource depletion (noticed today the Bakken shale play may now be peaking) world population will take an unpleasant turn downward. Iinterestedly, that downward motion may well save the planet, maybe not me or my one grandchild, but some. It may come to pass the Four Horsemen may be our only solution.
    Frankly, I have yet to see a single suggestion by a multitude of techno-triumphalist, enviro-spiritualist, or Road Warrior fanatics that offer a ray of hope. It appears to be too late to convince the masses. I personally hope there is a slow way down, be it stair-step or saw-toothed, to a simpler life but even with our own population of 340 million and rapidly growing, it is hard to imagine a happy group of organic farmers living in soddies on the Kansas plains. I do appreciate your work and this is some of the best reading I have seen in a while.

    1. Thanks for the note of appreciation for TOP’s work! The whole question of what counts as delusional dreaming and what as a reasonable idealism is an open one.There are plausible analyses which suggest that humanity is doomed to grow until we collapse. Our inability to pursue a saner path lends such analyses further credence.

      Nevertheless, we hope for something better. Along with most people posting to this website, we hope (leaving aside all calculations of probability!) that our societies can see their way clear to a less greedy and more grateful relationship to nature, shown in our economies and in our willingness to share the landscape more generously with other species. There are hopeful signs, but the overall trends are not good. –P Cafaro

  9. Technology is not magic. It’s not something qualitative (it works/it does not work), rather it’s quantitative: it works in a given extent, in a certain measure, under specific conditions. The same technology that could work in a given context -for example with a given concentration of CO2- might be not enough in another context (higher concentration of CO2, higher temperature, resource scarcity).
    The more we are and -consequently- the more greenhouse gases we emit in the atmosphere, the less likely a technology will work. The argument by H. Greaves: “let’s continue to grow without limitation, so we’ll get a magic technology that will solve all our problems” is not at all a scientific argument. I’m sorry, but it shows a total ignorance about what technology really means.

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