How should environmentalists think about immigration?

Between toxic calls for immigration controls based on racial criteria and hyperbolic denunciations of any mention of population issues as “ecofascist,” the room for intelligent and honest discussion of immigration policy is being gobbled up from both the Left and the Right. Yet the issue is too important to leave to the yahoos or the thought police. In a new article, Phil Cafaro and Jane O’Sullivan argue that respect for nature demands sharing landscapes and resources fairly with other species, which cannot be achieved without limiting human populations. For that reason, ecological citizens of all nations should support measures to decrease fertility rates and limit immigration, both of which are necessary to reduce currently excessive populations. An abridged version follows; the full article is available free of charge at The Ecological Citizen’s website.

By Phil Cafaro & Jane O’Sullivan

At the level of first principles, ecological citizens recognise intrinsic value in the non-human world, and an ethical duty to share Earth’s lands and seas fairly with other species (Washington et al., 2018). What this should mean in practice, in different parts of the world, is a matter for debate and democratic decision-making. But at a minimum it means preserving robust populations of all remaining native species, rather than continuing to displace and extinguish them. Ecological citizenship is centrally concerned to limit human demands on non-human nature, as part of living in community with other species. And because human numbers are a fundamental determinant of our demands and impacts on the natural world, ecological citizens should seek to limit the size of human populations. No matter which impacts we focus on (carbon emissions, water withdrawals from rivers, conversion of wildlands to crop lands) human societies that are always adding more people cannot limit their demands so as to fairly share the world’s limited habitats and resources with other species.

At the national level, this justifies non-coercive measures to decrease fertility rates, such as widespread provision of affordable contraception, educating people about the economic and environmental benefits of small families, improving gender equity, and prohibiting child marriage. But by the same token, it seems to justify limiting immigration, since the demographic consequences of high immigration levels can be equally consequential, and can readily overwhelm the benefits of lower fertility rates. Consider the United Kingdom, whose population stood at 65.4 million with a total fertility rate of 1.74 children per women in 2016 and which averaged about 230,000 annual net immigration between 1998 and 2017 (Figure 1).

Figure 1. Projections for the UK to 2100 at five different immigration levels, assuming current fertility persists. Data and methodology in Cafaro and Dérer (2018).

Continuing the status quo, the UK’s population is set to increase by over 15 million people during this century (>24%). Immigration plays the leading role in this increase, since fertility, at 1.79 children per woman, is significantly below replacement rate. Most of this projected increase disappears when net migration levels are halved, and when net migration is set at zero, the population decreases gradually (18% over 83 years). Conversely, doubling annual net migration leads to a 68% population increase by 2100, while increasing annual migration 4X—a rough proxy for “open borders”—would increase the UK’s population 167% by 2100.

How should an ecological citizen who is also a citizen of the UK respond to these facts? At a minimum, she should acknowledge their implications for efforts to create an ecologically sustainable society. Even on the basis of the Global Footprint Network’s purely anthropocentric analysis, the current UK population is using three times the nation’s biocapacity. Without attempting to anticipate how future technologies might rein in that overshoot, it is obvious that a UK of 54 million people will have more options for sharing the landscape generously with other species than a UK of 82 million, much less one of 175 million. Similarly, a less overpopulated UK will be able to reduce greenhouse gas emissions more sharply and in other ways do more to meet its global ecological responsibilities. As David Attenborough has said, “I’ve never seen [an environmental] problem that wouldn’t be easier to solve with fewer people, or harder, and ultimately impossible, with more.”

Experience shows that decreasing human numbers opens up possibilities to ratchet back impacts and share the land more generously with other species (Navarro, 2014), while increasing our numbers tends to foreclose such possibilities (McKee 2003). Based on such considerations, we believe that ecological citizens should support lowering immigration wherever current levels prevent population decline. One of the more hopeful signs of movement toward peaceful co-existence between people and nature is an increase in rewilding projects: efforts to regenerate forests, grasslands and wetlands, and restore the species and ecosystem processes that existed prior to human development. The organization Rewilding Europe explicitly acknowledges the positive role population decrease plays in this process. From western Iberia to the Danube delta, most of their projects include ecological restoration of abandoned agricultural lands. Continued population reductions could contribute even more to such successes in the future, allowing European nations to meet or even exceed the targets for protected areas set under the UN’s Biodiversity Convention and endorsed by the European Union.

Thankfully, Europe’s population trends are heading in the right direction to facilitate these efforts. At current fertility and immigration levels, the EU’s population is poised to decrease by 52.6 million people (about 10%) during the rest of this century. But again, future immigration policy can accelerate or counteract this trend (Figure 2).

Figure 2. Projections for the EU to 2100 at five different immigration levels, assuming current fertility persists. Data and methodology in Cafaro and Dérer (2018).

That citizens have a moral right to limit immigration into their countries, as a necessary corollary of the fundamental right of self-government, has been well argued elsewhere (Phillips, 2018). We believe that in many cases it is also their ethical responsibility to do so (Miller, 2016). A wise and just nation will strive to enact measures to ensure ecological justice between species and a fair distribution of wealth among its citizens. Neither of these goals can be achieved while opening up national residency to unlimited numbers of people (Cafaro, 2015).

The best way to influence global trends is by setting a good example. The “do as I say but not as I do” approach is rightly treated with disdain. Ecological citizens in Europe should be glad that it has become the first continent to break the back of the population explosion (United Nations, 2017). They should firmly reject efforts to stir fears about their “ageing populations,” which are an achievement, not a problem (Götmark et al., 2018), and work to put the right policies in place to realize the ecological benefits that shrinking populations can provide. Any nation that embraces its population peak and decline, and celebrates the environmental benefits, strengthens the will of others to follow suit. Any nation that actively works to prolong its own population growth undermines population stabilization efforts elsewhere. Already, the strident alarmism from developed countries about population ageing has led some developing countries to fear a too-rapid fertility decline, and to see their youthful, growing populations as a boon (O’Sullivan and Martin, 2016). Tanzania’s President Magufuli recently denounced contraception, saying “I have travelled to Europe and elsewhere and have seen the harmful effects of birth control. Some countries are now facing declining population” (BBC, 2018). Tanzania, with fertility over 5 children per woman, is on track to increase its population from 57 million in 2017 to 278 million by 2100 (United Nations, 2017). It is unrealistic to expect such huge population increases to be accommodated in Tanzania or elsewhere.

Of all the people alive who were born in developing countries, only around 3% have been able to emigrate elsewhere. Many of these have been relatively privileged, better-educated people whose skills are much needed in their own countries. As the populations of sender countries balloon, even a continued 3% emigration rate could overwhelm receiver countries’ capacity to absorb emigrants sustainably. From less than half Europe’s population in 1950, Africa is on track to triple Europe’s population by 2050, and in 2100 there may be seven Africans for each European (Figure 3). Clearly the removal of a relative handful of their more able citizens will not ease the social and environmental strains such population increases will cause in Africa or other swiftly growing areas. What these countries need is rapid fertility decline (Population Institute, 2015). Concerned citizens in the developed world should push for increased foreign aid, better targeted for ecologically sustainable development, and prioritizing family planning and empowerment of women. We should aim to alleviate the often-traumatic necessity for people to leave their homes—without undermining receiving nations’ own efforts to achieve ecological sustainability, or sacrificing other species’ very existence (Mathews, 2016).

Figure 3. Historical, current and projected populations of Europe and Africa, 1950–2100, according to the United Nations (2017) “medium variant” projection.

The developed world is already overpopulated (Kuhlemann, 2018). Global population growth will only end when enough individual nations embrace their own populations’ peak and decline. For these reasons, net immigration should be set at levels that allow for population contraction. This is necessary if we hope to create ecologically sustainable societies that share resources fairly with other species. Combined with reduced per capita consumption, smaller populations also will help developed nations to quit hogging a disproportionate share of the global ecological commons.

We believe ecological citizens have a duty to help our nations craft immigration policies that are racially non-discriminatory, economically equitable, and fair to other species and future generations. Not talking about immigration will not make the issue go away. Immigration policy still will be made, perhaps on the basis of xenophobia, or capitalists’ desire for cheap labor. It would be a shame if environmentalists abstained from these debates, thereby leaving future national population numbers to the whims of the environmentally ignorant. This—our current approach—is like saying: “We can address the 1001 effects of population growth, but not population growth itself.” Such an approach is obviously self-defeating, in terms of achieving our environmental aims. It also represents a missed opportunity to discuss our societies’ fundamental goals with our fellow citizens, and the need to respect ecological limits. These are precisely the kinds of discussions we all need to be having.

Adapted from “How should ecological citizens think about immigration?” by Phil Cafaro and Jane O’Sullivan, The Ecological Citizen 3 (2019): 85–92.



BBC (2018) Tanzania’s President Magufuli calls for end to birth control. BBC News, 10 September 2018.

Cafaro P (2015) How Many Is Too Many? The Progressive Argument for Reducing Immigration into the United States. University of Chicago Press, Chicago, IL.

Cafaro P and Dérer P (2018) New Policy-based Population Projections for the European Union, with a Consideration of their Environmental Implications. Working paper, The Overpopulation Project, Gothenburg, Sweden.

Götmark F, Cafaro P and O’Sullivan J (2018) Aging human populations: Good for us, good for the earth. Trends in Ecology and Evolution 33: 851-862.

Kuhlemann K (2018) ‘Any size population will do?’: The fallacy of aiming for stabilization of human numbers. The Ecological Citizen 1: 181–9.

Mathews F (2016). From biodiversity-based conservation to an ethic of bio-proportionality. Biological Conservation 200: 140-148.

McKee JK (2003) Sparing Nature: The Conflict Between Human Population Growth and Earth’s Biodiversity. Rutgers University Press, New Brunswick, NJ.

Miller D (2016) Strangers in Our Midst: The Political Philosophy of Immigration. Harvard University Press, Cambridge, MA.

Navarro L (2014) Rewilding Abandoned Landscapes in Europe: Biodiversity Impact and Contribution to Human Well-Being. Universidade de Lisboa, Ph.D. thesis.

O’Sullivan J (2014) Ageing paranoia, its fictional basis and all too real costs. In Goldie J and Betts K (eds) Sustainable Futures: Linking Population, Resources and the Environment. CSIRO Publishing, Melbourne, Australia.

O’Sullivan J and Martin R (2016) The risk of misrepresenting the demographic dividend. N-IUSSP April 18, 2016.

Phillips A (2018) Immigration Ethics: Creating Flourishing, Just, and Sustainable Societies in a World of Limits. Masters thesis, Colorado State University, Fort Collins, CO.

Population Institute (2015) Demographic Vulnerability: Where Population Growth Poses the Greatest Challenges. Washington, DC.

United Nations (2017) World Population Prospects. UN Population Division, New York, NY.

Washington H, Chapron G, and Kopnina H. (2018). Foregrounding ecojustice in conservation. Biological Conservation 228: 367–74.


Do you want to learn more about the solutions for overpopulation and actions towards sustainability? What actions we need to take on individual, community, national and global level? Check out the Overpopulation Project’s list of solutions!

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6 thoughts on “How should environmentalists think about immigration?

  1. Excellent and cogent rebuttal of open borders and daft alarmist calls for birth rates to be increased in Europe.

    Depriving impoverished and unstable countries of their brightest and best, does nothing to resolve growing inequality, overcrowding, and the regional instabilities which blight so many of the world’s poorer areas. Furthermore, it is rather selfish and short sighted for western leaders to continue to encourage this.

    The utopian thinking which still prevails, apparently believes that clever tech fixes, open borders and a right to migrate, whether legally or illegally, trump any legitimate concerns about overcrowding, social fragmentation, loss of national identity, species loss ,resource shortages, and pressures on infrastructure.

    All too often we are told that more people means more solutions and that the need to control population growth impinges on human rights. This school of thought appears to see no disconnect between endless population growth and conservation efforts aimed at preserving open spaces and protecting our rapidly dwindling flora and fauna.

    Witness the rescue missions in the mediterranean, which continue to ferry enormous numbers of would be migrants to overwhelmed ports and reception centres in Europe.

    The liberal media routinely condemn Fortress Europe, preferring to sneer at politicians like Italy’s Salvini, who has taken an increasingly popular stand against mass migration.

    At the same time, movements like Extinction Rebellion are lauded by the liberal commentariat. The UK’s Guardian is a prime example.

  2. In the U.S., we need to reduce immigration by 90% in order to achieve population stability.

  3. Well, as you know, the impoverished countries’ “best and brightest”, “better educated” and “more able” are often brighter than the rich countries’ brightest as well. Perhaps we should keep moving to the rich countries to help think up solutions to environmental problems — we might be able to come up with ways to tackle runaway overconsumption in rich countries, a much needed measure that can start right away and take place simultaneously with any and all discussion of overpopulation.

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