Robert MacNeil Christie, Author

Overpopulation has been an on-and-off issue for many decades. With the publication of Paul Ehrlich’s book, The Population Bomb in 1971, the issue came to a head…for a while. Then, with the apparent hopelessness of controlling population growth through public policy, few talked much about it for several decades. The idea of population control languished, if not its Eurocentric overtones.

However, the Chinese government instituted its one-child policy in 1979, to the dismay of many in the West, demonstrating that only an authoritarian dictatorship could accomplish strict population control—but at a cost that democracies found intolerable. Now, decades later, China has a population distribution skewed toward the elderly. Its centrally controlled economy is growing rapidly, contributing a growing share to the crisis of industrial overproduction and consumption. At the same time, China dominates the world market in solar panels.

Population control advocates in the global north pitch the importance of girls’ education and women’s rights in the global south—important in their own right everywhere—although they misapprehend the source of the impact of population on the living Earth System. Population times overconsumption equals ecological destruction—the malady of the North, which is spreading rapidly across the globe.

Is there an Optimum-sized Human Population?

The world’s human population recently passed 8 billion people. Opinions vary, but estimates of the optimum size of the human population usually range from a couple billion to a delusional ‘unlimited.’ Despite the wide disagreement about the numbers, certain factors are important and cannot be ignored by anyone who wants to get to an actual valid estimate. Yes, estimate. Such things cannot be precise, simply because so many factors are involved in the complex of living systems.

The relationship of humans to the Earth System, or the small segment of which is the habitat of a particular group, depends on many things, mostly to do with how the particular group’s behavior impacts its habitat and beyond. But in fact, the Earth System, and each of its complex subsystems—its ecosystems—has a specific ‘carrying capacity,’ that is, the amount and kinds of human activities it can tolerate without breaking down. It’s not so much how many people as it is what they do and how much carbon-spewing heavy machinery is involved.

The carrying capacity of a given ecosystem has not only its own particulars, but also has its own sensitivity to the impact of certain human activities upon it. However, even with the most benign group, such as a band of hunter-gatherers, the impact it has on its habitat determines the limits to its population size. The more industrially developed a population is, the smaller the capacity the ecosystem has to carry the load of that population.

It’s the Ecology, Stupid.

The entirety of planet Earth is a global ecosystem composed of many regional and local ecosystems, each interacting with others, adjacent, above, and below in size and complexity. Every species inhabiting an ecosystem participates in the complex interplay of life-forces within that ecosystem. In order for the ecosystem to remain in balance, each species—including humans—must operate within the parameters (on many dimensions) that constitute the boundaries of that system.

Industrial civilization has plundered along ever since its beginning with almost complete indifference to its impact on the ecosystems it loots. Well, the ‘chickens have come home to roost.’ Really, it’s quite simple. As long as the Earth was sparsely populated by humans there was much space into which societies could expand without immediate catastrophic consequences. However, when the population of a species overshoots the carrying capacity of its habitat (ecosystem) collapse is the most likely outcome. Today, the so-called ‘advanced’ nations of the global north have long since expanded their operations beyond every the carrying capacity of just about every ecosystem on the planet.

Catastrophic Consequences

So, it should be clear that limits to the growth of human societies exist even where humans have had an extremely low per-person impact on the Earth’s living ecosystems. The hunter-gatherers of the Kalahari Desert in southern Africa sustained small populations because their sparse savanna habitat had a low carrying capacity. However, industrial civilization has demonstrated its ability to have more and more per capita impact on the complex adaptive living systems that make up the whole Earth System every year, every month, every week.

That is why it is not just the total number of people on the Earth; it is all about what they are doing. The ‘population dilemma’ is not really a dilemma. Whether population or economic, growth is not an imperative once it approaches its limits. Planetary facts now constitute boundaries beyond which human populations cannot survive.  It is not about how many people ‘we can feed’—a patriarchal trope in itself. Instead, it is about how many are madly consuming vast quantities of the world’s limited resources. The report by Donella Meadows and her colleagues at MIT in 1972, The Limits to Growth, used some of the earliest complex computer models and the data available at the time, to simulate economic growth under differing conditions into the twenty-first century. The predictions of the ‘business as usual’ trend model were strikingly accurate in terms of the conditions today. The industrial era is all but over. The only viable civilized response is economic degrowth, shifting resources from multi-billionaire’s mega-yachts to provisioning basic needs for all people. That implies societal transformation.

We are, as I have put it elsewhere, at a tipping point, a turning point, a point of no return in the ‘progress’ of industrial civilization. Actually, it seems we face many tipping points in relation to the critical factors necessary to sustain a stable Earth System—the source of any societal security in the future. Industrial civilization is at a turning point whether we like it or not. The population crisis is really a crisis of industrial civilization, a turning point at which we will either transform the way we live, or plunder on into chaos and possible extinction.

The trajectory of industrial civilization as we know it is terminal. We cannot turn back and our current path offers only a dead end. Turn we must, but will we? We are already too far into the Anthropocene to avoid major population decline due to climate-disrupted crop failures, consequent mass migrations and armed resource wars. The most important question now is whether we will turn in a direction that will minimize the losses and pain, building a whole new kind of resilience by mitigating the sources of ecological/climate chaos as much as we can along the way. Will we turn in a direction that will allow us (and numerous other species, many of which we depend on because of their critical roles in the ecosystems we inhabit) to thrive in very different ways?