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Population is Part of the Equation

  • December 27, 2021

Happy New Year from UPEC! First, a quick announcement, and then some more substantial thoughts. The latter are longer than usual, but we hope you will give them a decent read, and please always reach out to us with comments and questions. Also, please share this email with your friends! 

As many of you know by now, UPEC plans to host a Conference on Population and the Environment in 2023 — roughly when the world’s population will cross the 8 billion mark. The conference seeks to explore, and increase awareness of, how rising populations (globally and locally) are exacerbating the climate crisis as well as other myriad environmental problems, from species extinctions worldwide to Utah’s disappearing Great Salt Lake and overly crowded canyons. The exact format of the conference is yet to be determined, but it may well combine elements of a traditional academic conference (with formal speakers) as well as “open space” elements through which we will workshop new ideas. We also plan to encourage youth to participate, perhaps via essay and Tik Tok video contests. 

We need the help of many Utah individuals or organizations to make this conference a success. If you are interested in getting involved, please email us at 

We at UPEC have been thinking a lot lately about the “E” in our title — Environment.

Indeed, the tangled relationships between population growth and the environment are key to understanding the complex system that is climate change, even if environmentalists so often ignore the controversial elephant in the room of population growth. 

Population is one of the three independent variables in the classic equation of environmental impact: I = P x A x T. I is the total environmental impact derived from the interactions among Population (P), Affluence (A), and Technology (T). All else equal — for the sake of argument, folks; obviously technology and affluence are always changing! — more people equal more things, more consumption, more fossil fuels burned, and more natural lands eaten up by agriculture and urban sprawl. 

Yes, T, as in technological advance, could in theory help us solve the climate crisis.

Currently, however, technological advancement is merely flattening the curve of per-capita fossil fuel use (which means we burn more carbon every year as population rises). Teslas still must be manufactured, shipped, charged with sometimes coal-burning power sources, etc. — and a clean-burning plane seems but a dream right now. Yes, A matters a lot, and in complex ways. More affluence in the developing world means that more people adopt global middle-class lifestyles every day, which augurs rising pollution per capita globally, but, then again, rising affluence also means that nations can spend more on environmental research and protections.

Population still matters a lot, too. Simply put, we are frying the planet, and every extra human being turns up the heat just a tiny bit. 

Of course, people consume (and eat) variously around the world (more on this in a moment). And, of course, where people live shapes their lifestyles and consumption, too. The average New Yorker emits less than a third of the greenhouse gasses of the average American. (If you’ve ever been in a large New York building, you know that often the last thing you want to do is turn on the heat — or retrieve your car from the garage!). But the inexorably compounding, aggregate harms of population growth cannot be wished away with such nuances. Indeed, with sea levels rising due to climate change, New Yorkers (and the rest of the 40% of Americans who live in coastal areas) have plenty else to worry about. 

So, while we recognize the importance of “A” and “T,” and do not discount them, the disproportionate level of focus given to them sometimes obscures the fact that slowing population growth is an important part of arresting climate change. At the least, we believe that there is space for groups such as ours to focus on the population variable in of the equation — and to engage in open-minded discussions about “P” itself. 

For example, though the idea behind GINKs (Green Inclination, No Kids) and BirthStrikers may seem fringe now, the concept is growing as more young people consider the “carbon footprint of procreation.” Reproduction is one of the greatest gifts and rights of human life, but obviously it can be overdone. Our current balance of perspective (gift of life vs. cost and burden) needs to shift. The personal sacrifices and costs of having children are well accepted, but discussions around the collective environmental burden of adding more humans to the planet during this era are not. 

To be sure, honorable people can and do disagree here. And we encourage everyone to read both sides of the debate. For example, a recent New York Review of Books piece (Anne Louie Sussman, “Conceiving the Future”) sympathetically reviews Jade Sasser’s On Infertile Ground: Population Control and Women’s Rights in the Era of Climate Change. Emphasizing the population movement’s very real history of unsavory arguments and campaigns (but minimizing how much it has changed), Sasser revives a long-standing claim that efforts emanating from the wealthy world to reduce the global population, which now emphasize climate change and women’s rights, constitute the old wine of racism and neocolonialism in the new bottles of sustainability and reproductive freedom. Concomitantly, Sasser rejects the links that, she proposes, environmentalists often identify between population and climate change. (UPEC’s size and reach in our community confirm that she exaggerates how much mainstream environmentalists engage population matters!)

“There is not, and never has been, a single, evidence-based model that has successfully calculated or predicted the global environmental impact of human numbers alone,” Sasser writes. 

Well sure, but this disingenuous argument is true only in the strictest sense. The logic here reminds us of a satirical medical study in the British Medical Journal. (Really, click on this link; you will enjoy the comic break!). The last time we checked, it is not the birds and pangolins burning fossil fuels. And few environmentalists or activists worry about population growth “alone” — hence the famous I = P x A x T formula. There is a legitimate argument to be made that a sustainable global population (based on current ecological overshoot) is around 4.5 billion, and more likely less. Every year we live, consume and waste at the current consumption rate (globally averaged) the planets resources and sinks takes 1.75 years to regenerate ( Every person, whether alive now or in the future, obviously contributes to climate change, even if arriving at the exact amount lies beyond our reach. 

“Ah,” those skeptical of worrying about population might retort, “that’s just it — you’re equating population growth everywhere, when the real problem is us in the rich world!” Sussman (the reviewer) wrote, “The argument that reducing human populations will help climate change has obvious appeal, but it overlooks several inconvenient facts … One is that people consume at almost comically disparate levels … the per-capita carbon footprint of an American citizen was 16.15 tons in 2017, compared with .15 tons for the average citizen of Madagascar.” The implication here is that we should stop worrying about population growth because it is increasingly centered in poor nations (and most especially in sub-Saharan Africa). 

This argument is disingenuous, as well. Yes, many population organizations seek to help women in the Global South improve access to family planning and healthcare — which is a worthy goal in and of itself. But almost every population group, including UPEC, worries deeply about the wealthy world’s profligate consumption and energy use — and the fact that the U.S. is one of the few wealthy nations with a population assured to rise for decades to come. We especially urge wealthy people to have fewer kids. 

We might also add that those who bizarrely deny a connection between population growth and climate change seem to focus so much on pure metrics of planetary survival that they ignore myriad other environmental issues, from dwindling biodiversity to access to quiet wilderness. Even allowing for a moment the strange notion that population growth does not exacerbate climate change, can anyone honestly deny that a world of, say, 4.5 billion, would enjoy more natural lands available for both wildlife and human recreation than our current world (to name just one of the many environmental goods that a smaller population would yield)? As one of the targets of Sussman’s review noted in a letter of reply, “Efforts to ease human population growth to a stop remain essential — necessary but far from sufficient — to afford future generations of children the possibility of inhabiting diverse and thriving terrains” (Stephanie Mills, in response to “Conceiving the Future”).

Finally, it is worth repeating an argument that UPEC makes often. Environmentalists who pooh-pooh population seem to imagine a dramatic shift in consumption and polluting habits is just around the corner. We at UPEC sure hope that such a shift is coming. But we are not betting on it. The fact that a very modest bill to address climate change has just failed in Congress — a bill that mostly offers subsidies for new technologies, and thus hardly asks us to roll back our underlying appetite for consumption — does not make us optimistic about dramatic change any time soon. Indeed, the concept that a global change in our consumption habits will meaningfully flatten the curve of climate change is magical thinking given the current social, economic, and political climate. Never in the history of humankind has anything close to that level of universal change occurred, especially not by willful decision making. Yes, the politics of climate change will change when things get worse. In the meantime, please ask yourself this rhetorical question: which is a more viable method of slowing the effects of climate change: asking people to stop at two kids, or rolling back the capitalist/consumption growth machine? 

Fertility trends are moving in the right direction.

It is thus our job to keep the boulder rolling downhill. The next time someone brings up a population issue — say, Elon Musk’s inane comments about how the world is headed for destruction because of lower fertility — go ahead and break the taboo. Mention how fewer people will help flatten the curve of climate change and lead to richer lives for all of us. (And please ask them to find UPEC’s webpage while you’re at it!) We at UPEC firmly believe that we need not sacrifice our quality of life to achieve a sustainable life in harmony with the natural environment. But, if we continue to ignore the elephant in the room of population growth, we may find ourselves without a seat in the final round of musical chairs. Or, at the least, the seat will be very very hot! We love babies. But we also believe that we need more serious discussions about humane and voluntary pathways to actively reduce human population numbers. And these two positions go hand in hand: we are motivated to make sure that today’s babies, no matter whether they live in Utah or Uganda, can grow up to enjoy a verdant corner of the Earth.

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