
In a short piece published recently in Nature, Stanford University Professor Emeritus and “Population Bomber” extraordinaire Paul R. Ehrlich worries that overpopulation, “one of the most important factors in the hunger nexus,” is not discussed by the Scientific Group for the UN Food Systems Summit 2021. This is a mistake, he writes, because “continuing population growth could overwhelm even current levels of nutrition” while being the source of other “existential threats” such as “biodiversity loss, climate change, pollution, groundwater overdrafting and escalating conflict.”

The biologist’s key proposition, usually traced back to an influential essay written by Thomas Robert Malthus over two hundred years ago, is that a significant reduction in human numbers would benefit the remaining inhabitants by giving them access to more and better resources. As was already obvious in Malthus’ days, however, a more numerous population in which individuals specialize in what they do best and trade with each other is always better off than a smaller one. Anyone concerned about the number of human beings is viewing them merely as consumers. People are, however, both consumers and producers. Their potential for wealth creation increases tremendously through trade and technological innovation.
For instance, in his correspondence with Malthus the French economist Jean-Baptiste Say argued that the belief that a reduced population would “enable those which are left to enjoy a greater quantity of those commodities of which they are in want” was nonsensical because it ignored the fact that a reduction in manpower simultaneously destroyed the means of production. After all, one did not see that “the wants of the inhabitants are more easily satisfied” in thinly populated countries. On the contrary, it was the “abundance of productions, and not the scarcity of consumers, which procures a plentiful supply of whatever our necessities require.” This is why the most populous countries were generally better supplied than the thinly populated ones.
In 1879, the American economist Henry George observed that “many communities still increasing in population” were also “increasing their wealth still faster.” Indeed, “among communities of similar people in a similar stage of civilization,” the “most densely populated community is also the richest” and the evidence was overwhelming that “wealth is greatest where population is densest; that the production of wealth to a given amount of labor increases as population increases.” The “richest countries” were therefore “not those where nature is most prolific; but those where labor is most efficient — not Mexico, but Massachusetts; not Brazil, but England.” Where nature provides few resources, George commented, “[t]wenty men working together will…produce more than twenty times the wealth that one man can produce where nature is most bountiful.” This was because the “denser the population the more minute becomes the subdivision of labor, the greater the economies of production and distribution, and, hence, the very reverse of the Malthusian doctrine is true.”
As was also well understood by many commentators, the greater the number of engaged human beings, the greater the likelihood of new beneficial inventions. As the British political economist William Petty observed over a century before Malthus, it was “more likely that one ingenious curious man may rather be found out amongst 4,000,000 than 400 persons.”
Furthermore, because present and future technological and organizational advances build on previous ones, there would never be an end to the development of better ways of improving on what exists, and inventing new systems, methods, and devices. In his 1944 The Theory of Economic Progress, American economist Clarence Ayres explained the exponential growth of technology by the fact that “the more devices there are, the greater is the number of potential combinations.” The supply of natural resources was similarly “defined by technology and not by ‘nature’” because the history of every material is “one of novel combination of existing devices and materials in such fashion as to constitute a new device or a new material or both.”
A few years before Ayres, the Progressive American historian Charles Beard had similarly observed that there can never be anything final about technological advances for the “solution of one problem in technology nearly always opens up new problems for exploration” and “[a]ctivities in one specialty produce issues for its scientific neighbors.” Beard saw no end to this process because of the “passionate quest of mankind for physical comfort, security, health, and well-being”. He added that until “people prefer hunger rather than plenty, disease rather than health, technology will continue to be dynamic” and that “[c]uriosity would have to die out in human nature before technology could become stagnant, stopping the progress of science and industry”.
Perhaps the best short overview of the anti-Malthusian stance can be found in an essay published anonymously by the British vicar Francis Minton in an 1889 issue of the Westminster Review:
Closer to us, uber-optimist economist Julian Simon believed that “it is only the past that gives us any insight into the laws of motion of human society and hence enables us to predict the future.” If the future was going to differ, he added, “the bias is likely to be in the direction of understating the rate at which technology will develop, and therefore underestimating the rate at which [natural resource] costs will fall.”
Despite the prevalence of the current apocalyptic environmentalist rhetoric and the self-inflicted economic wounds of lockdowns, we do not doubt that Simon will once again be proven right and Paul Ehrlich wrong, provided that humanity rediscovers its curiosity, motivation to explore and innovate, and the desire to participate in trade and exchange instead of blame and self-flagellation.
Pierre Desrochers, is Associate Professor of Geography, University of Toronto Mississauga.
Joanna Szurmak, is Research Services and Liaison Librarian, University of Toronto Mississauga.
READER COMMENTS
Pierre Lemieux
Nov 19 2021 at 3:12pm
Great post! I am tempted to add an optimistic but polemical note. Will I resist? I fear not. My point is that Ehrlich’s life will not have been in vain. For the benefit of young scholars, he powerfully illustrates the idea that one should continually submit one’s conjectures to the test of facts and that, when the conjectures don’t pass the test, one should cut one’s losses. Sunk costs are sunk. (Those who don’t know Ehrlich might want to have a look at my review of Paul Sabin’s book, The Bet.)
Frank
Nov 19 2021 at 9:00pm
And, and, all that extra CO2 in the air will increase agricultural productivity enormously! Earth can support many, many more people, at a time the rate of population growth is falling.
The apocalypse is not nigh, as Julian Simon appreciated.
Matthias
Nov 19 2021 at 10:24pm
Be careful with unqualified statements like saying that more population is always good.
In our observations more population makes people more productive at the margin. And at those margins we can easily feed more people right now with the extra productivity they unleash.
However, at ridiculously large populations there’s obviously a limit. Eg we might be able to feed a trillion people on earth with current technology and some belt tightening until technology catches up. But dump a trillion people into the 19th century, and there’s no way they could have been fed.
As an addendum:
I am fairly sanguine about a trillion people with current technology, because greenhouses are vastly more efficient than current agriculture per land area. They trade off more capital and labour requirements for that efficiency.
We are barely using the oceans.
If we really have to, we can use nuclear power (and geothermal etc) to produce artificial light for our greenhouses and stack them multiple stories high and let plants grow at night too. (Perhaps we need to modify the plants a bit to take advantage. But that should be doable without even genetic manipulation.)
And, of course, most people would probably need to go mostly vegan.
Pierre Desrochers
Nov 20 2021 at 4:09pm
In a market economy (ie., urbanized, long distance trade, ever greater division of labor). Obviously more population in stagnant economies isn’t a recipe for success, although as observed by Boserup, Chayanov, von Thunen, James Anderson and others, denser rural populations find ways to increase food production. This being said, not quite sure I agree that “at the margin” might be the best way to formulate this, at least for those of us who aren’t economists by training. The key difference between agriculture today and 2 centuries ago (with a world population about 1/8 the size) is that agriculture back then didn’t use much in terms of external inputs, whereas today almost everything on a farm (eg, equipment, fuel, fertilizers, pesticides, seeds, embryos, accounting software, marketing, etc.) is produced more efficiently elsewhere by someone else who also relies on an ever greater division of labor. So in the context of an ever more sophisticated division of labor (which obviously requires more people), food production will become ever more efficient and greener (in terms of using fewer inputs, including land), especially in the absence of barriers to trade, subsidies and other market distortions.
Jon Murphy
Nov 21 2021 at 7:08am
Sure, but that’s not the argument. Any shock to a system will be unsustainable. Rather, Ehrlich, Malthus, and others argue that there is some definitive upper bound that no amount of technology can overcome.
john hare
Nov 20 2021 at 4:25am
I am curious as to how this concept plays out in certain low tech/dense population situations. Middle ages Europe, last century India and China, and subsistence populations through history. It seems to me that certain stagnant (technologically) cultures that are living on the edge do not benefit from more population density. There is no efficiency gain in a hunter/gatherer society that rejects anything non-traditional.
What I can see around me today and projecting out over most of the world may not be valid in every instance.
Pierre Desrochers
Nov 20 2021 at 3:55pm
On greater rural population density and food population, you might want to look up Ester Boserup (who wasn’t as original as people who don’t know any history of thought make her out to be). This being said, greater population density in a market economy (i.e, ever more urbanized; ever more trade and division of labor over ever longer distances) have a remarkable record in terms of being fed ever more and better food at ever lower prices. We sketch out the argument in more detail in our book https://populationbombed.com/
Mactoul
Nov 20 2021 at 9:27pm
Malthusian idea is that population equilibrates with the carrying capacity. With greater technology, the carrying capacity would be more. The key corollary is that population is never less than the carrying capacity, unless war, pestilence or vice (meaning artificial means of contraception) intervene.
Derek Clark
Nov 20 2021 at 10:15pm
True, the world can support a human population many times larger than the present one. That is not the issue. The real issue is how much biodiversity can survive the impact of a greater global human population.
Personally, I wouldn’t want to live in a world where the only biodiversity are humans, crops, rats, flies and cockroaches.
Pierre Desrochers
Nov 21 2021 at 4:42pm
The more of us there is an advanced economies, the greener they become. One point that is missed by most analysts is that this happens because resources produced on the surface of the planet were increasingly replaced by resources extracted from below the surface (e.g., whale oil and petroleum). When the argument is raised it is usually attributed to Ed Wrigley who has been making it since the early 1960s… without ever giving credit to others who made it, sometimes in more detail, before him https://www.mdpi.com/1996-1073/13/20/5306
This is another reason why leaving carbon fuels in the ground is a dire threat to biodiversity
Shalom Freedman
Nov 22 2021 at 11:03am
It is strange that no one mentions we are living in a time where ‘demographic dearth’ has already become a problem in Japan, much of Western Europe and most developed societies. It is also strange that no one injects the environmental questions into the discussion. I also found strange the argument that larger population means greater inventiveness. I cannot really speak about scientific and technological areas but in the world I know best the world of literary creation this does not make sense to me. Biblical Israel Periclean Athens Elizabethan England the Russia and United States of the nineteenth century were not overwhelmingly large populations. If we think of the greatest period of American literary inventiveness the American Renaissance 1850-55 its great writers Melville Hawthorne Emerson Thoreau Emily Dickinson Walt Whitman were not new immigrants but scions of the early families of the society.
Pierre Desrochers
Nov 23 2021 at 5:55pm
Most environmentalists tell us that a shrinking population is not a solution if people keep getting wealthier and consume more resources. So overall resource consumption rather than population number is what we should be worried about.
As for a larger population, you should think of it as high density (i.e., a city) rather than something more abstract. To stick to your literary examples. From what I know, much of the Ancient Testament was written or put together during the Babylonian exile. You can also hardly think of Plato or Shakespeare without mentioning Athens and London. And there are always exceptions, but the classics of Russian and New England literature were written at a time of rapid urbanization. And then you could look at other creative endeavors and think of Florence, New York City, Silicon Valley, etc. Numbers and density do matter for human flourishing. The same person is typically not as creative in the middle of nowhere. Writers might be the exception, especially in this day and age, but they are certainly not the rule…
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