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:

The Malthusian theory does not accord with facts. As population grows, instead of production being less per head, statistics clearly prove it to be greater. The intelligence which is fostered in large communities; the advantages of the division of labour; the improved transit, which increases in efficiency with an enterprising people in proportion as numbers become large, and is impracticable until population has developed — are more than a match in the competition of production for any advantage a thinly scattered community may in some respects gain on a virgin soil. Malthus and his followers, while bringing prominently forward the needs of an increasing population, keep out of view the increasing means of supply which the additional labour of greater numbers will produce…. and so long as there are a pair of hands to provide for every mouth, with intelligence and energy ample production is assured, unless society erects artificial barriers by means of its laws regarding the distribution of wealth.

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.