Thesis #4: Human population is a function of food supply
Thomas Malthus was one of the most influential thinkers of all time. His father knew Hume and Rousseau, and his own paper–*An Essay on the Principle of Population*–forever changed the way we think about populations and food supplies. It has informed food security policies worldwide, and provided the basic underpinnings of our modern concern with overpopulation. In The Origin of Species, Darwin called his theory of natural selection an application of the doctrines of Malthus in an area without the complicating factor of human intelligence. Yes, Malthus’ work has been a major underpinning and influence on everything since. It’s a shame he was so incredibly wrong.
Malthus’ case is simple: population grows “geometrically” (exponentially), but food supply only grows arithmetically. So Malthus warned of a coming crisis where we would not be able to feed our burgeoning population–the “Malthusian catastrophe.” Of course, the failure of such a catastrophe to come to pass took a lot of wind out of Malthus’ sails. Malthusianism was declared dead after the 1960s and 1970s saw the greatest increases in human population ever seen, accompanied with higher calories per capita, thanks to the abundance of the Green Revolution. Cornucopians rejoiced as they saw the evidence come in that increasing population meant increasing prosperity for all: the realization of Jeremy Bentham’s credo, “the greatest good for the greatest number.”
If it seems too good to be true, that’s because it is. Even Bentham knew that the two factors needed to be balanced against one another, and that increasing one necessarily meant decreasing the other. As Garrett Hardin refuted it in his classic article, “The Tragedy of the Commons“:
A finite world can support only a finite population; therefore, population growth must eventually equal zero. (The case of perpetual wide fluctuations above and below zero is a trivial variant that need not be discussed.) When this condition is met, what will be the situation of mankind? Specifically, can Bentham’s goal of “the greatest good for the greatest number” be realized?
No — for two reasons, each sufficient by itself. The first is a theoretical one. It is not mathematically possible to maximize for two (or more) variables at the same time. This was clearly stated by von Neumann and Morgenstern, but the principle is implicit in the theory of partial differential equations, dating back at least to D’Alembert (1717-1783).
The second reason springs directly from biological facts. To live, any organism must have a source of energy (for example, food). This energy is utilized for two purposes: mere maintenance and work. For man maintenance of life requires about 1600 kilocalories a day (”maintenance calories”). Anything that he does over and above merely staying alive will be defined as work, and is supported by “work calories” which he takes in. Work calories are used not only for what we call work in common speech; they are also required for all forms of enjoyment, from swimming and automobile racing to playing music and writing poetry. If our goal is to maximize population it is obvious what we must do: We must make the work calories per person approach as close to zero as possible. No gourmet meals, no vacations, no sports, no music, no literature, no art…I think that everyone will grant, without argument or proof, that maximizing population does not maximize goods. Bentham’s goal is impossible.
So why were the Cornucopians so right, and Malthus so wrong? Because Malthus got the entire problem almost completely backwards–and it has remained backwards ever since.
Science has never been as unbiased as it would like to be–how could it? Skewing results is easily noticed, and rightfully condemned–as happened with such forgeries as Piltdown Man. Much more insidious is a lack of curiousity. We do not question recieved wisdom, and what we do not question we cannot understand. From Genesis 1:28 to the present day, we’ve viewed population growth as an inherent property of human nature. It has gone unquestioned. Certainly an Anglican country parson like Malthus would not question it. Malthus’ problem was how to feed so many people–a problem that could only be solved by misery, vice (i.e., contraception) or moral restraint (i.e., abstinence). The country parson, naturally, favored the same kind of abstinence programs in favor by the United States’ current conservative regime.
This is entirely backwards. What are all these people made of, fairy dust and happy thoughts? No, they are made of proteins–of food! Without a sufficient food supply, such a population cannot be achieved. We understand this as a basic biological fact for every other species on this planet, that population is a function of food supply. Yet we continue to believe that the magic of free will exempts us from such basic biological laws.
The usual counter-argument goes something like this: Humans are different from other animals. We can think. We can rationally observe the situation, and decide for ourselves how many children to have. While this is certainly true of individuals, groups are governed by much more deterministic criteria. For every individual who decides to be responsible and only have 2.1 children, another will take advantage of the space that individual has opened by having seven. The variation in values, thought patterns, beliefs and feelings of social responsibility ensure that the fertility rates of a group will rise to the carrying capacity possible, regardless of the intelligent, responsible choices of others in the community. Charles Galton Darwin, the grandson of that Charles Darwin, said, “It may well be that it would take hundreds of generations for the progenitive instinct to develop in this way, but if it should do so, nature would have taken her revenge, and the variety Homo contracipiens would become extinct and would be replaced by the variety Homo progenitivus.”
Education is often proposed as a solution, but Garrett Hardin already offered the best counter-argument to that strategy, again in “The Tragedy of the Commons”:
The long-term disadvantage of an appeal to conscience should be enough to condemn it; but it has serious short-term disadvantages as well. If we ask a man who is exploiting a commons to desist “in the name of conscience,” what are we saying to him? What does he hear? — not only at the moment but also in the wee small hours of the night when, half asleep, he remembers not merely the words we used but also the nonverbal communication cues we gave him unawares? Sooner or later, consciously or subconsciously, he senses that he has received two communications, and that they are contradictory: 1. (intended communication) “If you don’t do as we ask, we will openly condemn you for not acting like a responsible citizen”; 2. (the unintended communication) “If you do behave as we ask, we will secretly condemn you for a simpleton who can be shamed into standing aside while the rest of us exploit the commons.”
Every man then is caught in what Bateson has called a “double bind.” Bateson and his co-workers have made a plausible case for viewing the double bind as an important causative factor in the genesis of schizophrenia. The double bind may not always be so damaging, but it always endangers the mental health of anyone to whom it is applied. “A bad conscience,” said Nietzsche, “is a kind of illness.”
We can see this problem of overpopulation and education as a case of the Prisoner’s Dilemna. The best case scenario is cooperation; if neither prisoner confesses, both go off free. If we are all responsible, then we can save ourselves from self-destruction. But this is not what usually happens. The fear of abandonment prompts players to pre-emptively abandon the other. The question becomes a simple one of game theory, and the challenge to stop overpopulation by education, a contradiction of human nature.
All of this, however, is theoretical. This hypothesis is easy to test: calculate carrying capacity, and compare it to actual human population numbers. This is precisely what Russell Hopfenberg of Duke University did in his 2003 study, “Human Carrying Capacity is Determined by Food Availability.” As you might imagine from such a title, he found that the numbers lined up almost perfectly.
There is a significant complication in this, however, which critics of this stance are eager to point out. The First World is facing a population growth decline–the world’s richest nations are growing by the smallest percentages. Italy has been very concerned with its low growth rate, only 0.11% according to a 2003 estimate. Italy has the 201st highest population growth, and the 100th highest agricultural growth. Meanwhile, Singapore has the sixth highest population growth rate, and the 147th highest agricultural growth rate–out of 147.
If population is a function of food supply, why is the most significant growth taking place in those areas producing the least food?
The answer, I think, lies in globalization. How much of what you ate today came from your own bioregion? Unless you do a significant amount of your grocery shopping at Farmers’ Markets or eat only USDA-certified organic food, probably not a lot. In 1980, the average piece of American fresh produce was estimated to have traveled 1,500 miles before it was consumed. Interestingly, those same countries which produce so much food but don’t see it translate into their population, are also the heaviest exporters, and the impoverished countries with significantly rising growth rates are often the recipients. When the First World rushes in with foreign aid, food, and humanitarian aid to a desert area in the midst of a famine, we serve to prop up an unsustainable population. That drives a population boom in an area that already cannot support its existing population. The result is a huge population dependent on outside intervention that itself cannot be indefinitely sustained. Eventually, that population will crash once outside help is no longer possible–and the years of aid will only make that crash even more severe. In the same way that the United States’ policy of putting out all forest fires in the 1980s led to an even worse situation in its forests, our benevolence and good intentions have paved the way to a Malthusian hell.
Another part of the answer lies in our ecological footprint. In the passage above, Garrett Hardin made the distinction between the calories it takes to maintain a human body, and the “work calories” humans use to do anything else. While it is certainly true that population is a function of food supply, standard of living–how many work calories we receive, in addition to mere maintenance–is an important factor in that equation. Not only how much food is available, but how much food each individual demands. The dwindling First World has the largest ecological footprint; the growing Third World has the smallest. Italy comes in at #25 with 5.51 hectares per person (1996); Somalia is #114 with 0.97.
This is ultimately why education appears to have an effect on population: because higher education raises the standard of living, increasing the ecological footprint so that fewer people can live off the same amount of food, reducing the population. However, the problem we face is not one of Malthusian catastrophe. If we could not feed our population, we would not have such a population in the first place. The problem is the ecological consequences of such resource exploitation. Expanding ecological footprints do nothing to lessen this. Also, this trend can only continue so far, because the First World needs the Third. Our prosperity comes from the triumph of the corporate model, but the corporation itself runs on externalized costs. Our economy could never function if we had to pay the full and total cost for the luxuries we enjoy. Consider simply our oil costs–never mind the way it is built in to, say, our food. The Arab population oppressed under Saudi rule pays the balance for our cheap oil. Low prices at WalMart are made possible by cheap Third World labor. It is a grim economic reality that, given ten apples and ten people, for one person to have nine apples, the other nine must split one between them. In the conclusion to their 1996 study on ecological footprint, Wackernagel and Rees stated, “If everybody lived like today’s North Americans, it would take at least two additional planet Earths to produce the resources, absorb the wastes, and otherwise maintain life-support.” Since we have but one earth, this conclusion can also be spun around in the form that each of us essentially has three slaves whose existence is one of constant misery for our benefit.
Intelligence does not exempt us from basic biological laws–just as it has not exempted dolphins, crows or chimpanzees. Groups reproduce to the best of their ability, and the carrying capacity–their food supply–creates the ceiling of that ability. Populations will rise to their carrying capacity, and no further–even human populations. So Malthus has the problem entirely backwards. The problem is not how to feed so many people; of course we have the means to feed them, because if we didn’t, the population would not exist. The problem is the implications of so many people.
Every year, there is a certain amount of energy generated by the sun. This energy radiates in all directions, so there is only a small given percentage of it that falls on the earth. The total amount of solar energy available to our planet per time unit has a hard limit–what is called the photosynthetic capacity of the planet. This energy can be used in any number of ways. Plants turn solar energy into sugar; animals turn plant sugar into kinetic energy. Animals can eat other animals, and obtain the energy stored in their bodies, which they obtained from plants, which they obtained from the sun. But none of these conversions are perfect, and some energy is lost in each one; this is why an animal that eats other predators is almost unheard of. Also, each individual likely used some of the energy, before it was taken by the next link in the chain. As animals, we are always at least one step removed–and as omnivores, we’re just as often two steps removed. Also, we’re only one of millions, if not billions of species, all sharing the same, set amount of energy from the sun.
With the agricultural revolution, we found a way to convert biomass into human flesh, by reducing biodiversity in favor of our own foods. We increased the percentage of the planet’s photosynthetic capacity that we recieved. Solar energy that fell on an acre of forest would be divided amongst all the creatures, plant, animal and otherwise, that lived there. Solar energy that fell on an acre of wheat would go exclusively to humans. Our carrying capacity increased; not just that we had more food, but in more abstract terms, we were helping ourselves to more energy. Our population increased, so we cultivated more land. We had more people, so obviously we needed more food. We cultivated more land, and occasionally improved our technology to increase our yields per acre, but more food simply led to more people. Who required more food … the Food Race. But lurking high above our heads was an absolute limit: photosynthetic capacity.
In the 1960s, we saw the latest, greatest “win” in the Food Race: the Green Revolution applied the potential of petroleum to farming, allowing for vastly increased yields. We found a bit of a “cheat” to the natural order in fossil fuels. Now, we can burn through decades of solar energy every day to escape the limits of photosynthetic capacity. Essentially, we burn our past and take credit against our future in order to ensure our continued, exponential growth.
The Green Revolution set our carrying capacity to–well, whatever we wanted it to be. The population responded accordingly, with a huge initial jump, slowing as it reaches its asymptote. The scientists say that asymptote lies at 9 billion, and who am I to disagree? It seems like a perfectly reasonable figure. The population growth curve fits exactly what you would expect for a population adjusting to a suddenly raised carrying capacity–a huge jump, peaking relatively early, and extinguishing as it reaches the new “stable.”
Of course, it’s unlikely that this will remain the case for long. The Food Race goes on. 9 billion people will leave millions–billions, even–starving. Those people need to be fed. We need another “win” in the Food Race!
But 9 billion people is not sustainable. 6.4 billion is not sustainable. There is no sustainble solution for so many people. Only the Green Revolution can feed that many, and the Green Revolution is inherently unsustainable, because it relies on the consumption of a non-renewable resource.
The human race currently consumes some 40% of the earth’s photosynthetic capacity. This monopoly on the earth’s resources is having a devastating effect. We are seeing the extinction of some 140 species every day, some thousands of times higher than the normal background rate. Today, right now, we are seeing extinction rates unparalleled in the history of the earth. We are undeniably in the midst of the seventh mass extinction event in the history of the earth–the Holocene Extinction. Unlikely previous extinction events, however, this one is driven by a single species.
This is the true danger of overpopulation, not our inability to feed a growing population. As much as we would deny it, we depend on the earth to live. Dwindling biodiversity threatens the very survival of our species. We are literally cutting the ground out from under our feet.
Increasing food production only increases the population; our current attitudes about food security has locked us into what Daniel Quinn called a “Food Race,” by comparison to the Arms Race of the Cold War. Garrett Hardin began his famous article with this dilemma, and I’ll close with his assessment:
In our day (though not in earlier times) technical solutions are always welcome. Because of previous failures in prophecy, it takes courage to assert that a desired technical solution is not possible. Wiesner and York exhibited this courage; publishing in a science journal, they insisted that the solution to the problem was not to be found in the natural sciences. They cautiously qualified their statement with the phrase, “It is our considered professional judgment….” Whether they were right or not is not the concern of the present article. Rather, the concern here is with the important concept of a class of human problems which can be called “no technical solution problems,” and more specifically, with the identification and discussion of one of these.
It is easy to show that the class is not a null class. Recall the game of tick-tack-toe. Consider the problem, “How can I win the game of tick-tack-toe?” It is well known that I cannot, if I assume (in keeping with the conventions of game theory) that my opponent understands the game perfectly. Put another way, there is no “technical solution” to the problem. I can win only by giving a radical meaning to the word “win.” I can hit my opponent over the head; or I can falsify the records. Every way in which I “win” involves, in some sense, an abandonment of the game, as we intuitively understand it. (I can also, of course, openly abandon the game — refuse to play it. This is what most adults do.)
The class of “no technical solution problems” has members. My thesis is that the “population problem,” as conventionally conceived, is a member of this class. How it is conventionally conceived needs some comment. It is fair to say that most people who anguish over the population problem are trying to find a way to avoid the evils of overpopulation without relinquishing any of the privileges they now enjoy. They think that farming the seas or developing new strains of wheat will solve the problem — technologically. I try to show here that the solution they seek cannot be found. The population problem cannot be solved in a technical way, any more than can the problem of winning the game of tick-tack-toe.