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A large crowd gathers in Paris on September 24, 2022. (Photo: Vincent Koebel/NurPhoto via Getty Images)

We Can Solve the Climate Crisis Without Worrying About Population

"There are technical pathways to a world where 10 billion people can live well and stay within the biophysical limits of the planet's environmental systems."

Cynthia Kaufman

I am working on a book that argues that the world has enough for everyone. To get to that world of enough, we need better ways to organize society such that the politics of profit aren’t driving social, economic, and political decision making. One of the reviews I received on my manuscript took me to task for supposing that we could have enough for everyone without radically reducing the size of the human population. I had not engaged the topic because thought that worry about population had been put to rest. But apparently, I was wrong.

When I was in seventh grade, way back in the 1970’s, our biology teacher showed our class a very scary movie about the population bomb that would destroy human civilization if something urgent wasn’t done. I read a lot in the 1990’s about the feminist argument that population levels went down when women had more rights. I also read in that period about the ways that most of those promoting urgent action on population were generally racist and misogynist, and not paying enough attention to the politics of capitalism as a driver of wasteful lifestyles. For me those questions were closed decades ago. Because of that I was caught off guard by my reviewer's comments.

I will admit that I have heard a few times recently, said with bitterness and frustration, that the mainstream of environmentalism has suppressed honest conversations about population because we are afraid of the racial implications of that conversation. There are people who think that because humans are causing our environmental crisis, fewer of us would mean less of a crisis. People holding that view tend to believe that we need to act aggressively to limit the size of the human population if we want to keep the planet livable. They generally see the problem as based in places in the world, generally the global south, that have population levels that are still going up.

The reviewer who asked me to look into this question cited William Rees as a credible scholar who is raising alarm bells about the population. I took a dive into the work of Rees and Megan Seibert, a co-author of his. And I was not surprised to find that their view is wrong, and even worse, based on some bad faith arguments. After looking at the question, I believe that in fact, we can achieve sustainability with population sizes we are likely to see as the world’s population levels off later this century. There is no way to get to the population levels Rees and Seibert want without taking draconian measures. And I was not surprised to find that their work is haunted by the same specter of too many dark people in the global south that had animated the older generation of environmentally focused population alarmists. I decided to write this piece to bring that conversation out of the shadows.

The scientists have been very clear that we need to reduce our greenhouse gas emissions to 50% below 2020 levels by 2030 and to zero by 2050. We also need to preserve approximately 30% of the world's land mass by 2030 and 50% by 2050 to leave enough for other species to thrive, and to prevent the spread of zoonotic diseases. To achieve those goals, we need to completely remove fossil fuels from our economies, we need to stop destroying forests and allow them to regenerate, and we need to reorient our societies to being more resilient to the disasters that are inevitable, given the level of damage that has already been done.

Those of us active in climate movement who are silent on the question of population are not silent because we are afraid to mention the elephant in the room. We are silent because population control is not the place to look for solutions.

At present, there are three general approaches to thinking about environmental issues: techno-optimism, neo-Malthusianism, and environmental justice. The techno-optimists believe that with currently developing technologies, all of our environmental problems can be addressed, without requiring much deep social change or painful struggle. Governments need to add a few more regulations to make clean technologies economically more competitive in the market with dirty technologies. Governments need to subsidize those technologies. Businesses and consumers need to support innovation. Bill Gates, and Michael Bloomberg and Carl Pope have written books that tout the ability of smart business practices, good technology, and consumer choice, to solve the climate crisis. These thinkers believe that there is easily enough for all, if we just nudge society toward smarter choices.

On the opposite side of the spectrum are the neo-Malthusians who believe that no matter how much we embrace new technologies, there is not enough for the seven billion people who currently inhabit the planet to live sustainably, and there is certainly not enough for the 10-billion-person population we are likely to have as global populations level off later this century. They argue that we can only get to a world of enough with a drastic reduction in the size of the human population. Advocates of environmental justice, on the other hand, argue that we can get to a sustainable world for 10 billion people, but that we will need to fight against entrenched powers to get there.

Neo-Malthusianism has fallen out of favor in recent years, but strains of it persist to this day. In the 1970’s and 1980’s it was a dominant school of environmental thought. In his 1798 book, An Essay on the Principle of Population, Thomas Malthus argued that populations have a tendency to expand exponentially, while the food supply only increases in a linear fashion. His conclusion from that was that there was no point trying to solve the problem of poverty, because if you feed people, they will reproduce more, just creating more poor people. Of course, Malthus has been proven wrong by history. Human society has always produced enough food to feed everyone. Hunger is caused by political systems that keep that food from getting to the people who need it. Poverty is not an inevitable aspect of human society.

Since Malthus’ time, many thinkers have taken up his banner and have argued for reduced population as a way to deal with the overuse of resources. They have focused on population reduction as a core part of environmentalism. And in almost every case, they have focused on the populations of the global south as the ones that need reducing. In a 1986 interview, Earth First! founder Dave Forman said, "The worst thing we can do in Ethiopia [during a famine] is to send aid—the best thing would be just to let nature seek its own balance and let people there just starve."

In their 1968 book The Population Bomb, Paul and Ann Ehrlich set off alarm bells across the world that overpopulation was going to cause massive starvation and ecological crises. In that book, the authors approve of the strategy advocated by William and Paul Paddock whereby "Rich nations should send all their food aid to those poor countries that still had some hope of one day feeding themselves; hopeless countries like India and Egypt should be cut off immediately." The Ehrlichs wrote, "There is no rational choice except to adopt some form of the Paddocks' strategy as far as food distribution is concerned." As recently as 2013 Anne and Paul Ehrlich wrote an article that claims that overpopulation has been a more significant contributor to the climate crisis than overconsumption.

One of the more widely respected current neo-Malthusian thinkers is William Rees. Rees argues that most approaches to the climate and ecological crises are looking for solutions in the wrong places. He doesn't believe in renewable energy as a solution because those technologies rely on fossil fuels, and an extractive economy, to be produced. And they can never get us to the point where human beings can live within the biophysical limits of the planet, because,

Modern so-called renewable energy (RE) carriers – mostly wind turbine and solar photovoltaic (PV) electricity, but also now hydrogen – face major technical difficulties including possible materials scarcity; require massive increases in mining and refining involving fossil fuels, toxic wastes and slave/child labor; are ecologically and socially harmful; must overcome major distribution bottlenecks; occupy more space than many countries have available; and are impossible to scale up in a climate-relevant time-frame.

Because those technological solutions will not work, he argues that we need, a global population strategy to enable a smooth, socially just descent to the one to two billion people that could live comfortably indefinitely without destroying the ecosphere. The overall goal needs to be a smaller, steady- state global economy/society of fewer people living more equitably and securely within the biophysical means of nature.

Rees and his colleague Megan Seibert published a paper criticizing the scientific literature on the mainstream approaches to getting to a sustainable future. In it they argue that the only solution is drastic and rapid population reduction. They write,

We cannot stress enough that a non-fossil energy regime simply cannot support anywhere close to the present human population of nearly eight billion; this urgently necessitates reducing human numbers as rapidly as possible to avoid unprecedented levels of social unrest and human suffering in the coming decades.

There are two parts to their argument that are worth addressing, in order to look at the question of whether or not we can get to a world of enough. One is whether or not we need to push for extreme population reduction as a solution to the environmental crises we face. The other is the question of the feasibility of technological solutions to support a large population. Can we get to a sustainable world where everyone has enough, without taking drastic measures on population, or giving up modern lifestyles?

On the question of population, Seibert and Rees take pains to argue for a "socially just and humane" approach to population reduction. And yet, in line with most neo-Malthusians’ tendency to look at controlling the lives of far-away others when discussing population, Seibert and Rees argue that population reduction strategies should be focused on "high-fertility countries." What is troubling about this is that "high-fertility countries" are also countries with very low per capita environmental impacts. Those are not the countries that are driving our environmental crises. According to George Monbiot,

Between 1980 and 2005, for instance, sub-Saharan Africa produced 18.5% of the world's population growth and just 2.4% of the growth in CO 2 . North America turned out only 4% of the extra people, but 14% of the extra emissions. Sixty-three percent of the world's population growth happened in places with very low emissions.

In making their case for a socially just approach to population reduction, Seibert and Rees rely on the work of Colin Hickey, Travis N. Rieder, and Jake Earl. Those authors argue that reducing population should be a part of the wide variety of approaches taken to address the climate crisis. They advocate increased access to family planning services, education for women, advertising campaigns promote the value of fewer children, as well as economic incentives, such as paying for birth control, or removing tax incentives for having more children. They point out that many countries in the world have in place "pronatalist policies" that intentionally promote higher birth rates, and that some of those policies are not helpful to low-income women and children. In most cases, they are in place to serve reactionary forms of ethno-nationalism. The authors point to the coercive policies promoted in the recent past by China, India, and Singapore as morally unacceptable.

In a widely cited paper in Science, on population reduction and the climate, Eileen Crist et. al. argue, in alignment with Hickey et al, that a smaller population puts less stress on resources, and that there are other social benefits that come from humane approaches to reducing the population:

Wherever human rights–promoting policies to lower fertility rates have been implemented, birth rates have declined within a generation or two. Policies include prominent public discourse on the issue; prioritizing the education of girls and women; establishing accessible and affordable family planning services; provisioning modern contraceptive methods through diverse outlets; deploying health workers for grassroots education and support; making counseling for couples available; eliminating governmental incentives for large families; and making sexuality education mandatory in school curricula.

While Seibert and Rees focus on "high fertility countries" as the places to do the work of population reduction, Hickey et. al. very specifically do not. They acknowledge the higher impact of lower birth rates in high wealth countries, given the higher environmental impacts of individuals in those countries. And in a paper published after the one cited by Rees and Seibert, they argue for increased migration to solve the economic problems that might arise from the graying populations in the global north: "Supplementing fertility reduction with policies that facilitate the emigration of younger people from developing nations to developed nations could allow for both global reductions in GHG emissions and continued economic stability."

There is nothing wrong with supporting the humane policies that also lead to lower birth rates. Taking a measured and humanitarian approach to the issue, the authors of Drawdown write, "When family planning focuses on healthcare provision and meeting women’s expressed needs, empowerment, equality, and well-being are the goal; benefits to the planet are side effects." Population goes down as women have more power and people’s lives have some stability.

As of this writing, demographers believe that world population is likely to level of by 2050 at 10 billion people. Crist et. al. believe that the empowering policies mentioned above could get the world on target for a leveling off mid-century at 8.7 billion people. They believe that working to achieve that lower goal would be helpful for taking the pressure off other measures to achieve sustainability. None of these thinkers believes that humane policies can get you to the population of 1- 2 billion that Seibert and Rees say is required for a healthy environment.

While many neo-Malthusians express deep frustration at the silence in the climate movement around population, they have themselves to blame for that silence. Population has become a taboo subject among people working for a sustainable world because many of those focusing on its importance have tended to favor racist and draconian approaches. Their proposals invariably target population reduction schemes toward the bodies of those least responsible for the ecological crises we face. The loudest voices for population reduction have in most cases taken an explicitly, or in the cases of Seibert and Rees, implicitly racist approach to the issue.

If those arguing for "drastic and rapid reduction in birth rates" focused on policies that encouraged migration from the global south to the global north to balance labor needs, or if they focused on abortion and contraception rights for people in the global north, their ideas might be met with less skepticism. And as the following section shows, Seibert and Rees produced a bad faith argument about the inability of technology to support a larger population in order to buttress their conclusion that we need to limit the fertility of people in the global south.

A group of scientists working on sustainable technology published a response to Seibert and Rees’ paper. In it they go through each of Seibert and Rees' claims and show the paper to be based on an unacceptable non-scientific approach that includes selective (and hence biased) screening of the literature focusing on the challenges related to technologically enabled renewable energy solutions, without discussing any of the proposed solutions. Then, such a biased perspective is used to reject the possibility that RE may have a sustainable, rather than simply transitional, role in humanity’s future.

Instead, Seibert and Rees adopt the fatalistic and unimaginative perspective that the only way to solve the problem is to reject technological renewable energy solutions entirely and adopt an alternative "one-earth sustainability strategy" paradigm whereby just 1 billion people would inhabit the Earth, due to a forced reduction of population and RE would be derived only from wood, biomass, animal energy, and mechanical (not electric) wind energy.

The authors conclude, it is unfortunate, counterproductive, and ethically deplorable that the authors turn a legitimate discussion of the challenges of defossilizing the global economy into a political diatribe, castigating the potential for renewables to contribute to the overall solution. It is therefore absolutely necessary to stress that analyses like Seibert and Rees’ present not only a distorted perspective by cherry-picking references and ignoring the mainstream literature in almost every section of the paper.

There is a near consensus among the scientists who study the subject that there are technical pathways to a world where 10 billion people can live well and stay within the biophysical limits of the planet’s environmental systems. Mark Jacobson has done some of the most important, empirically grounded, work gathering together existing literature on the subject, and doing his own studies, to show how quick adoption of existing technologies can get us to sustainability and high levels of human well-being at projected population levels. Jacobson's work does not get into the question of the political barriers to adopting those sustainable practices. He is neither a techno-optimist nor an advocate of environmental justice. His work is focused only on the tough questions of which technologies should be adopted to get us to sustainability.

Arguing that a sustainable world at 10 billion is still possible is not the same as saying the that it will easy to get there, or that we actually will get there. In contrast to the techno-optimists, advocates of environmental justice argue that markets themselves will not lead to the adoption of sustainable ways of meeting society’s needs in the incredibly short time frames needed. The 25 major fossil fuel companies responsible for 71% of global emission since 1988, are fighting to the death to be able to continue to profit from their deadly products. They are also fighting for a continued use of throwaway plastics and agriculture based on nitrogen fertilizers, both of which are fossil fuel based. Agribusiness continues to destroy the Amazon basin. Fossil fuel companies are working to rip through one of the most biologically sensitive areas of the world, the Congo Basin, with the East Africa Crude Oil Pipeline.

Only a political fight to take away the power from those profiting from the Earth’s destruction will get us to the sustainable society scientists like Jacobson show us is possible. If we have democratic societies that take environmental justice seriously, we can find ways to make batteries with minimal damage to the environment and to the communities that live near where materials are mined. Mining can largely be replaced by mandated systems of recycling. Clean energy is already cheaper to build than fossil fuel-based energy. The world’s food systems can be made sustainable by lowering meat and dairy consumption and growing food with more sustainable practices. As I argue in The Sea is Rising and So Are We, almost all of the changes that need to be made will make the lives of most of us better rather than worse.

What is slowing our progress toward the crucial goal of a sustainable society are political systems that are controlled by fossil fuel interests, banks that support those interests, and those wishing to profit from our consumer lifestyles. For decades, the fossil fuel industry has spent hundreds of millions of dollars sowing confusion and doubt about the climate crisis. They succeeded in slowing down action for thirty crucial years.

And at this late date, when we need to reduce global emissions beginning immediately, and continuing at a sharp pace for the next 30 years, there are still many banks, pension systems, and investment funds which are pouring money into the development of fossil fuel infrastructure and funding deforestation. Governments all around the world are still subsidizing the fossil fuel industry at the rate of over $4 trillion dollars a year, $649 billion of that from the US. Most countries are, to greater or lesser extents, still allowing the profit motive, and the interests of those with capital, drive important social decisions.

Those of us active in climate movement who are silent on the question of population are not silent because we are afraid to mention the elephant in the room. We are silent because population control is not the place to look for solutions. And the global south is especially not the place to look for population control. The serious scholars working on population and the environment, such as Crist and her colleagues and Hickey and his colleagues, above have not been marginalized or shunned for their work. They take a measured and thoughtful approach to reducing population somewhat to take pressure of the transition to a sustainable world. Their approach includes advocating for women’s rights, access to family planning, and increased levels of migration from the global south to the global north. Anyone advocating for lowered levels of population, who is not actively working for those things, and who is looking at draconian measures to limit the rights of people in the global south, will continue to be marginalized in conversations about how to make this planet livable.


Our work is licensed under Creative Commons (CC BY-NC-ND 3.0). Feel free to republish and share widely.
Cynthia Kaufman

Cynthia Kaufman

Cynthia Kaufman is the author of "The Sea is Rising and So Are We", "Challenging Power: Democracy and Accountability in a Fractured World" (2020), "Getting Past Capitalism: History, Vision, Hope" (2012), and "Ideas for Action: Relevant Theory for Radical Change" (2016). She is the director of the Vasconcellos Institute for Democracy in Action at De Anza College. Her website: cynthiakaufman.net.

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