The Human Animal in the Circle of Life

This is the fifth article in a series about the Earth-system – how our planet has shaped us as human beings, and how we, in turn, have shaped it. Read the series: Part 1 | Part 2 | Part 3 | Part 4 | Part 6 | Part 7 | Part 8 | Part 9 | Part 10 | Part 11 | Part 12

Basic ecology teaches us that there is no life without the flow of energy. Most of life’s energy is sourced from the sun: Sunshine falls upon the land and water, at a finite daily rate, where it’s absorbed either kinetically—as heat, driving winds and ocean currents and evaporation—or chemically, by plants whose photosynthetic powers can trap it within the chemical bonds of carbohydrates, a form of fuel that can later be burned as needed by most living cells, for growth, health, and reproduction.

Almost every living thing on the planet takes its energy from this sun-fed system, either tapping into it closer to the source, like the plants who first capture it, then the deer who eat the plants, or further from the source, like the big cats who eat the deer, or the fungi and microbes who eat all of these after they’ve lived and died. Humans eat all of these things too. After we die, we’re also eaten by the fungi and microbes; the materials that make up our bodies are returned into the soil and the air, and eventually reabsorbed by the plants. Energy and materials flow through this circle of life—really, multiple interconnected circles, or a web of life—with each species occupying its place, or niche, within the flow.

Like every other being on Earth, humans once lived within the constraints of our energy niche. That is to say, we lived directly upon what our environment could immediately provide, existing in a kind of balance with whatever landscape we called home. The materials we consumed were returned to the land at roughly the same rate that we took them in, through the waste we produced, including our excrement and the bodies of our dead. If we produced waste too rapidly for the local ecosystem to readily reabsorb it, that waste became pollution, throwing us out of balance, degrading our home ecosystem and thus diminishing its productive capacity. If we consumed resources faster than the Earth could replenish them, again out of balance, the landscape became overdrawn, exhausted, degraded.

Genetic evidence suggests that the ancestors of the peoples living on the Andaman Islands first landed there at least 25,000 years ago—and likely closer to 60,000 years ago. For tens of thousands of years they successfully lived in sustainable balance with their island ecosystems: dots of land with clearly constrained limits to growth. The ongoing destruction of their cultures, due to colonisation by the British and then mainland Indians, undoubtedly represents the loss of a valuable knowledge system for how to live on Earth.

But at a balanced rate of consumption and waste, our population could grow to fill the carrying capacity of the land—that is, the number of humans the local ecosystem could sustainably support in a given way of life—and there it had to stabilise. If we spoiled the landscape by over-extracting resources, over-polluting, or otherwise carelessly destroying the integrity of the ecosystem, we would overshoot the land’s carrying capacity, impoverishing ourselves in the same moment. The feedback from the local ecosystem in response to such ecological overshoot could be quick and stern, as resources then declined in the following season or year, causing hunger and other problems. Societies that resisted adjusting their ways to accommodate the needs of the ecosystem, who instead forced their environment to bend to their own priorities, would collapse. Successful communities learned from their costly mistakes and adjusted their lifestyles accordingly.

There could be no hoarding of surpluses, no wanton annihilation or dismemberment of the local ecosystem in this kind of immediate-return economy, as typified by nomadic foraging cultures. Living within the constraints of the land doesn’t easily allow for the kinds of socioeconomic differentiation we know today. Without surpluses or hoarding, there could be no rich or poor people, no persistent economic stratifications or classes of people. And since most individuals were reasonably adept in the necessary skills of provision and survival, there was little leverage for tyranny or coercion.

Of course, every community has selfish individuals who nevertheless seek to over-exploit resources or to control other members of their group. There are always those who remain heedless of the consequences to others when they upset the ecological balance or community life, so long as they find some personal advantage in doing so. Such greedy or antisocial members of any group have probably always gotten away with some amount of bad behaviour. But excessively exploitative, damaging, or tyrannical social campaigns could not have persisted for long among nomadic foraging peoples, certainly not enough to define a way of life for an entire community.

Among nomadic foraging groups there is enormous social and cultural resistance to greed or wilful attempts to concentrate social power. This plays out in what are called reverse dominance hierarchies. That is, anyone who aggressively attempts to promote themselves, control others, hoard resources, or force actions seen by others as unfairly self-serving will actively be pulled down by their community, through humiliation or violence—sometimes even to the point where the unhappy group murders the aspiring tyrant.

The Indian subcontinent saw relatively few megafaunal losses during the global Late Quaternary extinction event, between 50,000–10,000 years ago. Losses included two elephant species, Palaeoloxodon and Stegodon; a hippopotamus, Hexaprotodon; a zebra-like equine; and ostriches (still found in Africa). However, in today’s age of radical deforestation and industrialisation, just within the last 300 years India has already lost its aurochs, two types of rhinoceros, cheetahs, and civet cats, plus several bird species. At least 97 more Indian species are presently on the verge, including its last elephants, lions, dolphins, and tigers.

A narcissist may also be levelled by the dissolution of their group through attrition: people just leave the braggart’s company—‘vote with their feet,’ as anthropologists like to say. Or they may expel that individual. This was possible because there was almost unlimited freedom of movement among people in nomadic foraging societies: individuals were free to walk away; their broadly seeded networks of kinship and reciprocity assured they had somewhere else to go, whether to join another group just across the valley or hundreds of miles away. This isn’t to suggest that no one ever held a leadership position or achieved some degree of coercive power over others; however, to the extent that leadership or coercive power was institutionalised, it remained impermanent, limited, and contingent.

In any case, the Pleistocene climate had always been too unstable for hoarding to become entrenched as an economic or social system. Before the Holocene, conditions had been constantly in flux everywhere, substantially rearranging patterns of rainfall, plant growth, and animal migrations every dozen or score generations. But it would eventually take hundreds of generations, living in stable, warm climatic conditions for societies to transition toward systems of persistent socioeconomic inequality: The drift toward full dependence upon surplus food production for storage and later consumption (delayed-return economies) itself took thousands of years. And after that, the ossification of rigid social hierarchies took thousands more.

But for most of humanity’s time on Earth, such a length of stable, temperate conditions, as in the Holocene, had never occurred. And so for nearly all of human experience, immediate-return economies and fluidly egalitarian structures or fluctuating hierarchies defined the baseline social context of ongoing human evolution, as human knowledge systems, interrelationships, and cultures grew thicker and more complex. Until at least the mid-Holocene, roughly five thousand years ago, all human societies functioned primarily on the basis of mutual aid, grounded in social bonds and cooperative cultural norms, and deeply connected to the health of their home ecosystems.

Something has certainly changed in more recent history. Few people today live in the kinds of balanced and egalitarian societies that were ordinary for 99 percent of our time on Earth. Instead, most people today are stuck within the deeply entrenched system of socioeconomic hierarchy that is our modern, industrial civilisation. This same global system has largely dismantled healthy ecosystem functioning across large portions of the Earth, rerouting the flows of energy and materials away from benefiting ecosystem robustness, but instead toward feeding the desires of our single species. There are now so many humans that we’re literally crowding out other forms of life, as we destroy their habitats for our cities, farms, pasturelands, mines, dams, roads, and other infrastructures.

By 45,000 years ago, South and Southeast Asia were already home to most of the world’s people. Around 35,000 years ago, when new stone toolmaking technologies jumped in sophistication, indigenous South Asian populations began growing even faster. Perhaps this surge of humans caused the local megafaunal extinctions. Further innovations in tool technologies, the spread of cereal agriculture, and patriarchy have each played a role in rapid population growth at various times since then, such that South Asia has remained among the most populous regions in the world.

The human enterprise now claims 25% of Earth’s net primary productivity—that is, the total amount of the sun’s energy converted into food by plants—an amount that’s doubled over the last century alone. And since sunlight falls at a finite daily rate, all the other living beings—who continue to subsist within the economics of immediate-return energy flows—have less energy to live on. We’re fundamentally changing the energy and material flows of our biosphere in a way that results in a massive increase of humans and our domesticates—alongside a commensurate diminishment of all other life. In fact, today humans make up 36% by weight of all the mammals on the planet, while elephants, whales, tigers, bears—almost every wild animal you might think of—are fast disappearing, altogether accounting for only 4 percent of mammalian biomass. This is estimated to be an 85% reduction of land-dwelling, wild mammalian biomass since modern humans first left Africa and, given the decimations of whaling, this figure would be substantially higher if marine mammals were included.

Even so, during the same span of time, the overall mammalian biomass has multiplied by nine times, due to the massive expansion of domesticated animals, especially pigs and cows. Today, birds farmed for human consumption—mostly chickens—make up almost three times the biomass of wild birds. Human activity has reduced Earth’s plant biomass by half since the dawn of agriculture and obliterated 60 percent of all mammals, birds, fish, and reptiles in just the past 60 years. And the rate of annihilation is accelerating.

Meanwhile, humans produce an extreme surplus of food and other materials, most of which is consumed by those near the top of the prevailing socioeconomic hierarchy. As of 2020, the human-built world—all the asphalt and concrete and machines and plumbing and plastic currently in use—now outweighs all the world’s biomass, every living thing on the planet taken together. Each week, artificial materials are continuously produced at an amount equivalent to the total body mass of all living people. This doesn’t even include our industrial pollution.

Industrial capitalist society is built upon this production of surplus food, materials, and extra-somatic energy for use by some humans more than others. It blithely presumes that the ecosphere will readily provide the energy and materials to fuel this overconsumption and then absorb the mountains and rivers and islands of concomitant waste and pollution—including all the excess carbon dioxide we emit. The cost of this is—as it has always been—the destruction of the local ecosystem, which today encompasses the whole planet, thus driving the mass extinction of non-human species and the destruction of many human groups as well. The result is a biosphere critically lacking in biodiversity, frightfully over-polluted, morbidly out of balance and overwhelmed by the over-population of its apex predator species: humans. We’ve already exceeded six of the nine known planetary boundaries for civilizational stability. Today our species is in a perilous state of ecological overshoot. Climate change is merely one symptom of this condition.

We are strangling the web of life, triggering an extinction event such as our planet hasn’t witnessed since the age of the dinosaurs. We might glean from this the same fundamental lesson our ancient ancestors would have heeded, when they were not so separated from the ecological feedbacks of their actions. Indeed, some communities around the world who still follow lifestyles much more closely connected with the land have seen the signs of our ecological overshoot and have tried to warn us, repeatedly.

But what was it that prompted such a dramatic change in the way so many people chose to live, to shift from immediate-return to delayed-return economies? From socially egalitarian, decentralized, diverse and fluidly inter-linked communities to deeply stratified, centralized, relatively homogeneous and bounded nation-states? When did it all begin to change? Why? And as a species, why are we not (yet) suffering population decline when we so utterly despoil our environment, as our ancestors suffered if they ruined theirs? The answers may not be what most of us are led to presume. I will attempt to tease them out in the forthcoming essays of this series.

Usha Alexander trained in science and anthropology. After working for years in Silicon Valley, she now lives in Gurugram. She’s written two novels: The Legend of Virinara and Only the Eyes Are Mine.