Many readers of our blog probably see no problem with “overpopulation,” but we sometimes get negative responses when we use the word, even from colleagues who largely share our views. Why is this so? How should overpopulation best be defined?
By Frank Götmark, Jane O’Sullivan and Phil Cafaro
In contrast to other organisations dealing with population growth and its associated negative impacts, TOP uses the word overpopulation in our name. When we started two years ago, that surprised some people. They wondered, what is “The Overpopulation Project”? In one sense, it’s humanity’s present project: the process of increasing human numbers globally to the detriment of wildlife, our common climate, food security, green urban spaces, and more. Our project’s overall aim is to understand and explain the connection between human numbers and these problems, in order to help societies address them more effectively.
But for many people who, like us, have worked to draw attention to the risks of excessive human populations and promote family planning to minimize further population growth, “overpopulation” is a dirty word. According to them, it can paint us as misanthropes: perhaps not as bad as Thanos in the film Avenger’s: Endgame, but still somehow guilty of wanting to eliminate surplus people by unethical means. Of course this is a misrepresentation, but it happens. Should we self-censor to be a smaller target for criticism, or should we present our honest view: that humanity is already overpopulated, and that by denying it we turn our backs on the best options for averting humanitarian and ecological crises?
What does science say about overpopulation? The word can be applied to any species which exceeds the carrying capacity of its habitat. For a while, the species might continue to thrive, but only by running down its “natural capital,” consuming things faster than they can regenerate and disrupting the balance that sustains each year’s bounty. Ultimately, the degraded habitat will no longer support such numbers and the population collapses. But people can modify environments to support more people. They can use technology to get more goods and services from the same resources, and they can gather and trade resources over vast distances far from where they actually live. This has led to lengthy discussions about the question “How many people can the Earth support?” (Joel Cohen’s 1996 book of that name ran to 534 inconclusive pages). The answers depend on value judgements, such as what quality of life we want people to have and how much we value preserving wild places where other species can thrive; also on what technologies we might conceivably draw upon in the future. Maximum and optimum population sizes are likely to differ.
All of this creates a large grey area, with much room for disagreement about what constitutes overpopulation. The Global Footprint Network, for example, defines “overshoot” by contrasting a population’s overall consumption with its country’s total biocapacity. This definition assumes perfect substitutability between different biocapacities, as well as an entitlement for humans to consume it all. But even this selfish and overly optimistic treatment concludes that we’d need 1.7 planet Earths to sustain our current behaviours. Whether we could retreat from this excess purely by consuming less and improving technology, without also stemming humanity’s population growth, is beside the point – for now, we are overpopulated by their assessment.
Grey areas aside, we believe there are limits beyond which human overpopulation becomes undeniable. Surely overpopulation exists where 1) people are displacing wild species so thoroughly, either locally, regionally, or globally, that they are helping create a global mass extinction event; and where 2) people are so thoroughly degrading ecosystems that provide essential environmental services, that future human generations likely will have a hard time living decent lives.
This definition recognizes that people are not on this planet alone, we share it with perhaps 10 million other species, and that in any case, we don’t want to live like rats in a cage. We don’t just want to live, we want to live well, we want our grandchildren to live well, and we want them and their grandchildren to live in a biologically rich world. On this definition, most nations, and the world as a whole, are overpopulated right now, and getting more overpopulated with each passing year.
So why are people uncomfortable using the term? First, some people deny overpopulation exists, referring to recent progress in human well-being around the world. Second, the term may cause communication problems, if not explained well. Some colleagues and other conservationists, both in rich low-fertility countries and poor high-fertility countries, feel it gives the wrong impression about whose interests are being pursued. Let’s consider these two issues in turn.
Regarding the first, we do not deny that the average living conditions for many people around the world have improved in recent decades. But this general case is often taken too far, since in absolute numbers undernourishment, for instance, persists and has even increased compared to 60 or 70 years ago. Furthermore, future improvements in peoples’ lives are commonly taken for granted, despite the UN’s forecast that we face another 80 years or more of substantial population increases, while environmental capital, from groundwater reserves to climate stability, are being run down already. But pointing to the fact that food and freshwater cannot increase indefinitely as the human population grows usually has little effect; many will argue that Malthus was proven wrong in the 19th century, Paul Ehrlich in the 20th, and smart Homo sapiens will solve new problems through clever management or new technology in the 21st. And the more people, the more brains to solve the problems!
But note, this is a common response from political and intellectual elites whose privilege has allowed them to do well and feel confident about the future. The general public heading to work on crowded buses, low-paid workers fighting flooded labor markets, or poor farmers worried about droughts or subdividing their properties among their numerous children, may have more negative and realistic views about population increase. You can see this contrast when the public responds to newspaper reports or opinion pieces focused on solving environmental problems through technical solutions; check the online comments after the article, where readers often recognize population growth or overpopulation as the missing piece in the texts, and express skepticism that solutions which ignore it will work.
Those who have any interest in wildlife are even less inclined to argue away overpopulation, since they are aware of current negative trends for wildlife numbers. One study of mammal population trends for the period 1900-2015 concludes, of “the 177 mammals for which we have detailed data, all have lost 30% or more of their geographic ranges and more than 40% of the species have experienced severe population declines (>80% range shrinkage).” Another study, published last year, concluded that North American wild bird abundance decreased by 30% during the last 50 years, an astonishingly rapid rate of loss. Overpopulation has obviously contributed to these negative effects on other species, so those who care about other species are less inclined to argue away its existence.
The second issue is that in some circles, such as in discussions regarding international development aid, the term “overpopulation” seems to have become taboo. Among our colleagues in Africa, “overpopulation” can create negative responses, despite our sharing similar views on the negative effects of population growth and on the needed solutions, such as greater financial support for family planning. For example, in a response to TOP’s website where we highlighted overpopulation, an African colleague wrote: “Your piece also ignores the issues of inequities within and across countries which is at the heart of the poor state of human conditions we see in different parts of the world today. It is NOT overpopulation that is sending millions of children to bed hungry each night. It is not overpopulation that is responsible for the massive ecological devastation in Africa today.”
There is a lot to unpack in these words, but implicit is the idea that citing overpopulation means denying the inequities of colonial legacies and modern exploitation. Even worse, that the person citing overpopulation wishes to impose some sort of penalty on poor, high-fertility countries, rather than identifying a crucial area in which they need help. We’re all raised on stories where adversity is characterized by villains and heroes, so it’s hard for some to grasp that naming is not blaming. Yet it is difficult to argue that population growth has played no role at all in driving deforestation, overgrazing, soil degradation and other environmental harms in Africa, not to mention shrinking land holdings, burgeoning urban slums and insufficient access to food, infrastructure and services. And with all that is known about crowded labour markets leading to low wages and exploitative working conditions, can it really be argued that population growth plays no role in driving economic inequality?
No country outside OPEC has achieved middle-income status without first reducing its birth rate substantially through voluntary family planning, and every country which did so, regardless of their colonial legacy, has seen substantial betterment. By denying the problems generated by continued rapid population growth, our colleague’s commendable desire to address economic equity could contribute to worsening it. Such denial also ignores the fact that limiting future population growth is likely to be an important factor in whether African nations are able to preserve their spectacular wildlife heritages.
Pointing all this out does not mean arguing against greater economic equity between nations, fairer trade relations, or increased foreign aid—all of which we support. Nor does it mean acquiescing in overconsumption by wealthy people, or pretending that overpopulation is only an issue in the developing world. As we say on our web site: It is important to realize that overpopulation exists in many rich countries with too high rates of consumption as well as in many poor countries with too high fertility rates. Every effort should be made to reduce high consumption rates as well as high birth rates; in combination, these two measures would create a much better future for people on the planet.
On this view, the fact that some rich nations have aging and declining populations is “good for the Earth,” as we argued in a 2018 paper. On this view, each nation, each political leader, each citizen, can contribute to creating sustainable societies by addressing both consumption and population issues, and their interconnections.
We agree that population isn’t everything. But addressing overpopulation is important in creating societies that sustain good human lives and maintain the existence of other species. We ignore it at our peril. In recent decades, many environmental advocates have done just that. Their neglect or denial has made it much harder to deliver the reproductive freedoms that people in high-fertility countries want. The program FP2020, started in 2012 to revitalize languishing family planning efforts, has helped many women in many countries receive contraception. But it has fallen well short of its targets due to weak political will in both donor and recipient countries.
Still, the fight to address overpopulation continues. At the end of last year, the organization growing out of the World Scientists’ Warning to Humanity organized a seminar on overpopulation at the annual United Nations climate change summit (COP 25 in Madrid). Several of our competent colleagues argued there that overpopulation is a major threat to climate stabilization and that there are solutions to help us deal with it. Watch video of the seminar here and send it on to others who may be wondering how to define overpopulation and what to do to deal with it.
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