ONE OF THE COMMON PLACES of environmental writing these days is a population forecast of 10 billion people, by century’s end. Some environmental experts are incredulous that such a number can be approached, predicting catastrophe or a combination of catastrophes entailing much suffering, before humanity stabilizes at lower numbers. But other environmental observers, calling themselves more optimistic, are looking for strategies that might sustain the expected billions. They hope that with innovations in crop genetics, irrigation technologies, fertilizer application, efficiency gains, and energy transitions the planet might feed, water, house, educate, and medicate the coming 10.
What would be the consequences of following that path?
Such a world is only possible by taking a spellbindingly life-abundant planet and turning it into a human food plantation, gridded with industrial infrastructures, webbed densely by networks of high-traffic global trade and travel, in which remnants of natural areas are zoned for ecological services and ecotourism. What’s more, 10 billion consumers will require mega-technological support: offshore dike projects; more dams; desalinization plants; scaling-up of industrial aquaculture; genetic modification of crops and animals to meet climatic and consumer demands; the cultivating of so-called marginal lands to grow plants for biofuels; the spread of the fracking scourge; climate engineering at global and regional scales; and the spread of factory farms.
In such a world—whatever it augurs for humanity, which seems bleak to say the least—the exuberance of Life will suffer a tremendous blow. I use the word Life, with capital L, to mean something akin to what life scientists call “biodiversity”, though the term is often mistakenly conflated with numbers of species.
While numbers of species are a significant dimension of Life’s fecundity, Life is far greater than that. Life is bewildering in its creative expressions, its beauty, strangeness, and unexpectedness; its variety of physical types and kinds of awareness; its dynamic, burgeoning, interweaving world-making. In the “interdisciplinary” dance of Life—where phenomena of physics, biology, biochemistry, behavior, awareness, and chaos jostle in established and spontaneous patterns—Life creates abundance. For example, hundreds of millions of eggs wash to the sea’s edge, feeding multitudes before a fraction develop into the organisms that spawned them. Prey species proliferate wildly in response to the pressure of their predators. Enormous, ever-on-the-move ungulate herds do not decimate the lush grasslands that feed them, but the grasses grow because of them, and together, the animals and grasses, along with a vast array of soil life, create more soil. Incalculable numbers of marine creatures once sustained the tens—perhaps hundreds—of millions of sharks and whales. Freely moving, pristine rivers teemed with fish even in recent history. Great flocks of birds graced skies, wetlands, and seashores. Land, sea, and air animal migrations have not only told the seasons’ stories but contributed to bringing the seasons into being. The intermingled manifestations of Life on Earth—when Earth is allowed to manifest them—have no finitude.
Rather than taking sides between the forecast of impending tragedy versus optimism about “feeding the world,” there is another way to tell the near future’s story. Humanity can choose to live on a planet of Life instead of haplessly plunging toward a human-colonized planet effectively on dialysis. To live on a planet of Life it is necessary to limit ourselves so as to allow the biosphere freedom to express its ecological and evolutionary arts.
But the wisdom of limitations—of human numbers, economies, and places of habitation—is rarely entertained in mainstream thought for what it is: the elegant way home and the surest means for addressing the deepening—and likely self-endangering—problems of extinctions, ecosystem destruction, rapid climate change, freshwater and topsoil depletion.
The path of limiting human population is rarely entertained for it is assumed to be unrealistic and thus politically inexpedient. Is it really more unrealistic than planning to feed an unchecked population? Let’s look closely at what taking that course would entail.
By most expert accounts food production will have to double by 2050 to meet demand. It is well known that most arable land is already in cultivation, and that the areas where wild creatures live are already pushed to their limits, so the effort to increase food production is invariably escorted by the caveat that it must be done without “further damage to biodiversity” or “taking over more uncultivated lands.”
The most pernicious thing about this formula—grow more food, don’t damage more nature—is that it insinuates the current damage our food system inflicts is acceptable and irreversible. Hands down, however, food production is the most ecologically devastating enterprise on Earth. This devastation is ignored in the belief that humanity’s food-producing capacity is not constrained by natural limits. In fact, that humans are exempt from any natural carrying capacity.
The demographic idea of carrying capacity refers to the maximal population of a species that its environment can support without that environment becoming too degraded to support the species in the future. If a species exceeds its carrying capacity starvation, disease and death will follow until the population is brought back within a supportable range. While this natural law applies broadly in the animal kingdom, it is widely believed that it does not apply to us.
In the early 19th century the Reverend Thomas Malthus predicted that, since population grows faster than food production, human numbers would outstrip the available food supply. But the two centuries following his analysis did not see a human population crash. So Malthus’s theory came to be viewed as repudiated and the doctrine of human exceptionalism received a victorious boost.
Malthus’ foreboding forecast did not come to pass, however, because humans converted Earth’s most fertile lands for agriculture, took over extensive swaths of natural areas for domestic animal grazing, appropriated half the world’s freshwater, applied enormous quantities of synthetic chemical and fertilizer pollutants, and plundered untold numbers of wild fish.
Human carrying capacity has been extended not simply because we are so clever at manipulating natural processes and inventing stuff, but through forcefully taking over the carrying capacity of other life-forms, and, in the process, wiping them out regionally or globally. Moreover, this exemptionalism serves conveniently to bolster the idea of human expansionism. For exemptionalism teaches that because the human species is so special it is proportionally that much more entitled.
The question of whether or not there are natural limits to our food-producing ability is ultimately not so interesting: the experiment required for the final verdict is an ugly one either way.
Already, cropland uses a portion of the planet the size of South America, while land for grazing farm animals eats up an even larger share—an area the size of Africa. Effectively, humanity has seized the temperate zone for agriculture, wiping out all or most former nonhumans and ecologies in order to mine the soil. Regarding the seas, the human food factory has demanded that 98 percent of them be fishable. As a consequence, only about 10 percent of the big fish are left, and there is no end in sight.
Furthermore, food production contributes at least 30 percent of anthropogenic greenhouse gases. It consumes at least 70 percent of the freshwater taken from ecological watersheds. It also depends on constant applications of pesticides, herbicides, and other biocides. Streams, rivers, lakes, wetlands, and estuaries around the world are fouled or deadened by agricultural runoff and farm animal excrement. So how is the amount of food we produce to be doubled or more without additional damage?
The social mission to double or triple world food production is madness. But the proposal to move deliberately in the direction of more than halving human global population, and simultaneously radically changing our food system, is not.
If parents were voluntarily to choose having an average of one child, then the world’s population—instead of climbing toward 10 billion—would stabilize and begin descending toward 2. It is an intelligent and compassionate action that many people would be willing to take if they became properly informed about the planetary emergency we are in.
Wherever concerted policies to lower birthrates have been implemented, they have declined with alacrity. The combination of heightened public awareness, the empowerment of women, and the availability of affordable, up-to-date reproductive services yields swift declines in birthrates. Such declines follow from a straightforward bio-cultural cause: the vast majority of women, when they attain free choice, rarely want more than one or two children, because numerous offspring are hard on the female organism and take time away from other personal pursuits. As population analyst Martha Campbell has shown, this natural female propensity for few offspring surfaces straight away, once barriers to reproductive services are removed and freedom of choice becomes reality.
Significantly lowering our numbers facilitates a more harmonious way of life on Earth in at least two ways. First, many problems—from traffic jams, to health care budgets, to climate change—become more tractable as the dimension that magnifies them is curtailed. Second, a lower population will enable the radical transformation of an industrial food regime that is currently bludgeoning ecologies, wild and domestic animals, and human wellness. (Four leading causes of disease and death are linked to industrial food: heart disease, diabetes, cancer, and stroke.) The whole world can indeed be fed with organically grown, nutritious food, by prioritizing local and regional food economies, caring for and building soil, using diversified, smaller-scale farm operations modeled on natural ecosystems; and by forsaking high quantities of animal foods for the occasional consumption of such foods.
We need an authentic green revolution. Instead of holding demographic growth as given, and a biosphere-wrecking food system as normal, let’s imagine a world where we actively renounce both. Such a world would be dramatically more beautiful and sane—with abundant food, ecologically and ethically produced; with streams, rivers, lakes, and estuaries returned to being living waters; with deforestation halted and grassland ecologies reinstated; with the extinction crisis arrested and seas thriving again with Life; with climate change made more manageable via carbon-sequestering forests and decelerated emissions. Indeed, what is detaining us from creating a civilization in harmony with wild Earth?