Fig. 3
HUMAN NATURE
I ka wa mamua, i ka wa mahope.
(The future is in the past.)
HAWAIIAN PROVERB
Chapter 9.
THE MAKER AND THE MADE
In the 1990s, Mao County in central China ran out of wild bees. The reasons, as usual, turned out to be various. Pesticide use was too heavy, honey hunters were taking too much honey, people were clearing too much of the forests in which the swarms made their homes. But Mao County is an apple-growing region, and in the end not enough bees remained to properly pollinate the trees. By 1997, almost all of the apple growers were doing the job by hand, dipping pollen from blossom to blossom using brushes made from chopsticks and chicken feathers and cigarette filters. That image—human pollination crews teetering in the branches like scarecrows scattered by a windstorm—travelled around the world. It seemed to be an object lesson in the importance of maintaining the diversity of other species, and of how desperate life can become when natural systems collapse.
Fifteen years later, three American researchers published an economic analysis of what they called “the parable of the bees,” and turned the story upside down. Mao County’s apple growers told interviewers that they actually preferred hand pollination. Human pollinators, it turned out, were better at getting to every blossom, performed cross-pollination more efficiently and could work in windy, rainy weather that a bee would never venture out in. What’s more, wages paid to orchard workers were often spent in the local area, further bolstering the economy. Worker bees don’t head off to the bar or the grocery store when their day is done.
“Destroying and replacing the free gifts of nature can be an economic benefit,” the researchers concluded. They might have gone on to argue that we should immediately begin to identify other ecological processes that could be replaced with human labour and technology, but in this case the team, led by the economist John Gowdy of Rensselaer Polytechnic Institute in Troy, New York, moved in the opposite direction. The parable of the bees, they argued, is not that natural systems aren’t always valuable, but that it’s dangerous to measure the value of nature only in dollars and cents. “Market valuation is an exercise for people who have lost all sense of ecological embeddedness,” they wrote. “This is us, the global economic human of the twenty-first century.”
Here is the most uncomfortable lesson to be taken from the history of nature: that we can survive—thrive, even—in a degraded natural world. Mao County found it could live without its bees. London and Paris feel much the same way about their long-lost brown bears. Saskatchewan and Kansas prosper without their tumbling buffalo herds; China and Egypt carry on in the absence of their elephants. Large areas of the globe have lost all or nearly all of their largest animals and most ancient forests, and yet they remain desirable locations for people to live. The entire continent of Europe is a tastefully appointed ecological wasteland—rich in human culture, antiquities and innovation, but poor in the abundance and variety of species.
The nature that we live with is a choice. Human beings have witnessed a broad spectrum of states of nature, ranging from continents and oceans teeming with megafauna to landscapes so reduced and transformed that we have to get the neighbours together just to pollinate the flowers. No one, certainly no single generation, decided our trajectory from a richer to a poorer ecological world. Different arrangements of people have taken more or less from their environment in different places at different times, but as a general pattern each one gave itself limited permission to degrade nature as they knew it, then adapted to live with the consequences. It’s another maxim from historical ecology: we excuse, permit, adapt—and forget. We’ve been adrift as a species, making choices without remembering what our options are.
After tens of thousands of years, the accumulating effects have become more difficult to ignore or overlook. In the year 2000, Eugene Stoermer, a biologist, and Paul Crutzen, an atmospheric chemist, published a paper arguing that the Holocene—the name given to the epoch in geological time that began at the end of the last ice age—was over, and a new era driven by human transformation of the globe had begun. They called this new epoch the Anthropocene, which translates roughly as the Human Age.* As a starting date, they proposed the late eighteenth century, pointing in particular to James Watt’s invention of the steam engine, which accelerated humankind’s technological power. As evidence that our species’ impact was substantial enough to be thought of as a new geological epoch, Crutzen and Stoermer pointed out—among other factors—that the Anthropocene planet is home to 1.4 billion cattle; pumps more sulphur dioxide into the atmosphere through coal and oil burning than all natural sources of that gas combined; features a new and widespread weather condition called “smog”; has had 50 percent of its land surface physically reshaped by human hands; and is so badly polluted with carbon dioxide from fossil fuels that the global climate will likely be affected for at least the next fifty thousand years. We have changed the earth to such an extent that even if it was possible to suddenly lay down our tools, we would still end up with a world of our own creation. The choices going forward are our own, however squeamish we may be about human hubris, however unwilling we may be to shoulder responsibility for the rest of creation. We are, as one wildlife biologist put it, “condemned to art.”
This is nowhere more true than when it comes to biodiversity—the oddly technocratic term we have given to the variety of life that inhabits the planet. Attempts to estimate the total number of species have produced figures ranging from 3 million to 100 million; a recent effort—considered conservative, as it is based on the degree of known variety within the most fully studied categories of species—predicts that the earth is home to approximately 8.7 million cell-based life forms, 87 percent of them still unknown to science. Not surprisingly, the species that have already been catalogued tend to be the most conspicuous—relatively large, widely distributed and numerous. The species that have yet to be discovered will mainly be small, local and obscure.
Let us be blunt: we can lose a bunch of them without threatening our own survival. Warnings that we put ourselves in danger when we drive species to extinction often make use of the “rivet hypothesis,” first put forward by the biologists Paul and Anne Ehrlich in 1981, which suggests that the components of any ecosystem are like rivets on an airplane: you can only remove so many before a structural failure causes a catastrophic crash. It is probably more accurate to compare nature to a city. You can subtract from a metropolis nearly endlessly over time. Many types of removals, such as the elimination of a single parking sign or the bench at a particular bus stop, will go almost unnoticed. Even major changes—imagine the closure of every sports arena or the permanent loss of mobile phone service—do not make a city unlivable. Daily life for the residents may become more unpleasant and less aesthetic, it may constantly demand innovation and adaptation, but life itself tends to go on with a shrug and a weary smile.
Many of the more than four thousand species that the International Union for Conservation of Nature classifies as critically endangered could wink out of existence without the slightest ripple being felt around the world. Would we miss the Bolivian chinchilla rat? It’s known only from a single misty forest of about one hundred square kilometres, located nearly two thousand metres above sea level in the mountains of central South America; even there the rat may be specialized only to rocky areas. Cola praeacuta, a small evergreen tree from the same lineage that gave the world the caffeinated cola nut, has no recorded common name in any language and is found only in the foothills around Mount Cameroon in Africa; were it to vanish from the face of the earth, other trees would readily grow in its place. The Himalayan quail, once a fairly common species on the grassy slopes of steep peaks in a patch of northwestern India, has not been seen since 1876. It’s believed that the quail may still exist, but in terms of its impact on human life, it might as well already be gone.
The disappearance of these species would change
the world: among other things, the chinchilla rat helps distribute certain seeds in the cloud forest; Cola praeacuta is useful as firewood for local villagers; the Himalayan quail surely shaped the mountain meadows in subtle ways, and once upon a time was hunted as a game bird. Still, all three species and plenty more could shuffle into the void without endangering humanity’s future. We might add, more or less at random, the poso bungu, a small fish known from a single lake in Indonesia; the Kythrean sage, which grows on limestone hilltops on the Mediterranean island of Cyprus; and the bizarre-nosed chameleon of the mountains of Madagascar. The list is long. A city has a lot of parking signs, a lot of bus-stop benches.
There are limits. We may be able to ride the current wave of extinction, but we do know we can’t ride it all the way down. Taken as a whole, natural systems are the basis of life on earth, as easy as that may be to forget in times when meat comes from the grocery store and water from the turn of a tap. Grasslands still feed our livestock, and forests still store and filter our water. Even wild foods remain critically important to modern life: the oceans provide us with about 90 million tonnes of fish each year, feeding billions of people every day. The community of living things, from microbes to megafauna, is endlessly producing oxygen, generating topsoil, stripping our chemical pollutants from the water, slowing erosion, controlling pests, moderating the climate. Economists try to place a value on these “ecosystem services,” but the numbers—one pioneering estimate was $33 trillion—are too large to be more than abstractions, and too small to express the reality that we are nowhere close to being able to replace a living world with human technology. Nature is priceless. As the environmental historian Donald Worster says, “We have not learned how to live on a planet that is dead.”
The contributions of individual species, too, surround us every day. Thousands of medical drug treatments are derived from plants, animals, fungi and other life forms; most famously, perhaps, childhood leukemia can now often be cured thanks to a drug developed from the rosy periwinkle, a flowering plant from Madagascar that once was threatened with extinction. Add up the most important crops of every nation: we currently rely on 103 species to supply 90 percent of the world’s plant-based foods. Our capacity to feed a growing population will surely benefit from the thirty thousand additional species that are believed to have edible parts, including such oddities as the marama bean, Tylosema esculentum, an African vine that can produce large edible tubers and nut-like legumes in 50-degree Celsius heat and less rain than falls in Death Valley, California; or the medlar, a Northern Hemisphere fruit that is harvested mid-winter, after it has started to go rotten on the tree. Nor is the practical value of a species always so earnestly survivalist: the first man to deliberately jump out of an airplane and land on the ground without using a parachute, Gary Connery of Britain in 2012, did so in a wingsuit inspired by the anatomy of flying squirrels while using steering techniques he learned by watching birds of prey called kites.
We’ve begun to understand that even our own bodies are richly diverse ecosystems. Some ten thousand varieties of microbe have now been found on and inside of healthy human beings, in mixtures unique to each individual. These other species’ cells outnumber human cells ten to one, though it may be a comfort to hear that these additional cells are generally far smaller, so that less than three kilograms of each person’s body is accounted for by them. Most are beneficial, helping to digest food, process vitamins and prevent disease, and many are so thoroughly adapted to living as a part of us that growing them in a lab is as difficult as growing an orange tree in the Arctic. We wouldn’t live long without these companion life forms, and vice versa; biodiversity is a part of what makes us human.
The idea that other species make important contributions to our lives and, taken as a whole, form the basis for our continued existence on this planet, is one of the most important of the past twenty years. It has also had the unfortunate side effect of encouraging the view that every living thing should be valued in terms of its practical, measurable usefulness to people. Extend this notion far enough, and it even becomes possible to weigh whether the absence of any particular species—such as the bees in Mao County—may be more valuable to human interests than its presence.
Several years ago, I found myself asking a wildlife biologist named Joe Truett to justify his work in exactly such utilitarian terms. We were sitting under an elm tree in a desert grassland preserve in southwestern New Mexico. Bison, which had been brought back onto the landscape, were filing across the sunburned basin. On the horizon, in the craggy Fra Cristobal Range, mountain lions once again hunted a reintroduced population of desert bighorn, and from our patch of shade Truett and I scanned the skies for the aplomado falcon, a bird of prey with beautiful gunmetal-blue and cinnamon markings that had been released in the area as part of an effort to re-establish a U.S. population extirpated in the 1950s. Why, I asked, did all or any of this matter?
Truett answered the question in what is now the usual way: biodiversity contributes to the stability and resilience of the planet; ecological services have economic value; restored landscapes serve as useful reference points for understanding natural potential and the effects of change. None of these arguments was good enough for me that day. I wanted him to somehow prove that the scene we were looking at was as essential as it felt to me in that moment. I wanted a single crowning reason that we should live with more natural abundance, not less, a richer rather than a poorer state of nature.
At last, Truett said this: “I like it.”
It isn’t said so plainly nearly often enough: we can simply prefer a wilder world. Debates over how to use natural wealth often pit one set of interests against the other: fishermen versus fisheries scientists; oil companies versus indigenous people; housing developers versus outdoor sports enthusiasts. The question at the heart of these conflicts—whose nature?—is not the first one we should be asking. That larger question is which nature? What kind of nature do we want to live with? The possible answers are not the domain of science or economics alone, but involve every one of us. As a question of individual and collective values, it is perfectly legitimate to like nature, want more of it and to stake your position on grounds of curiosity, awe, mystery and delight.
We won’t keep species like the chinchilla rat, Cola praeacuta, or Himalayan quail alive because we need to, only if we want to. Every species, when closely examined, has qualities that could one day lead to breakthroughs in human advancement, but in the meantime, they are never less than cause for wonder. The common North American bird called the chickadee, for example, appears to grow a larger brain in autumn, when it needs to remember where it is caching seeds for the winter, then shrinks it again in the spring in order to conserve energy for mating. The great frigatebird is able to put half of its brain to sleep at a time, helping to explain how the animal has been recorded in flight over open ocean for up to twelve days straight. The Eskimo curlew, hunted to extinction in the early twentieth century, is thought to have had among the most efficient muscle fibres of any bird; if a curlew was a small airplane, it could fly 1,500 kilometres while burning the same amount of fuel that ordinary aircraft consume while taxiing out to the runway. Another avian species, Australian brush-turkeys, construct piles of leaves and branches, often as large as five metres in diameter and waist-high to a human being; the birds’ eggs are then incubated by the warmth of the decaying vegetation. The compost mound of an experienced male brush-turkey will never vary in its internal temperature by more than two degrees.
The duck-billed platypus, a freshwater mammal that is Australia’s answer to the beaver or otter, can apparently “smell” the electricity generated by the movements of prey while it feeds blindly in muddy water. Polar bears were once thought capable of swimming no more than an already impressive 120 kilometres, until a female was recently recorded covering 687 kilometres in an uninterrupted nine-day swim, without sleep, water or food, all while navigating due north using senses that no one yet can explain
. Polar bears, incidentally, are so well insulated by their fur coats that they are effectively invisible to infrared cameras. Elephant seals can hold their breath for up to two hours; the human record is eleven minutes.* Ant cities in Africa may involve the removal of forty tonnes or more of soil, plunge eight metres into the ground and have hundreds of well-ventilated underground rooms, all built without any guiding architectural mind.
If we are now coming to understand that the hundreds of other species that live on us or in our bodies are a part of what makes us human, then perhaps the same can be said of the species that live outside of us. The planet’s other life forms reveal so many ways of being that we could never imagine them if they didn’t already exist in reality. In this sense, other species don’t only have the capacity to inspire our imaginations, they are a form of imagination. They are the genius of life arrayed against an always uncertain future, and to allow that brilliance to wane out of negligence is to passively embrace the death of our own minds.
We have been looking at the natural world as something separate from humankind, using the common definition of nature as everything that is not us and is not made by us. It’s one useful way to see the world, but to gain a wider view, it is ultimately essential to bring our own species into the picture—just another living creature, after all, as miraculous as the rest. The question—which nature?—applies to human nature as well.
Michael Soulé, one of the founders of conservation biology, believes that the nature we surround ourselves with goes beyond questions of values to actually shape human beings as a species. In the postwar era of the twentieth century, anthropologists doing research around the world began to notice a remarkable pattern: hunter-gatherers could see better than the rest of us. In fact, it appeared that the further an individual was separated from hunter-gatherer ancestors, the more likely he or she was to be genetically predisposed to myopia, also known as short-sightedness. The effect was dubbed “relaxed selection”; when a group of people no longer depends on long-distance eyesight to feed themselves or keep watch for menacing animals, the common genetic mutation that causes myopia will have little or no effect on a person’s likelihood of surviving or producing offspring. The evolutionary pressure on that trait is lifted. A keen nose, too, was once as vital to human survival as it continues to be for many wild animals. Some 60 percent of the genes associated with the sense of smell are now inactive in most people, a loss that has likely taken place only since the dawn of agriculture some ten thousand years ago.
The Once and Future World Page 13