In various places around the world, the fossil record shows that not long after humans arrived, large mammals—megafauna—vanished. It’s long been hypothesized that humans hunted the massive creatures to death—such would explain the suspicious timing. But could a bunch of ragtag early humans, absent modern weaponry, have really managed to kill off tens of thousands—more, even—of these large, powerful creatures?

Yes, it turns out. Megafauna’s great size came at a cost: a slow reproduction schedule, with maybe only one new offspring every other year. Such a strategy was, for a long while, very successful. Once a child made it to adulthood, it was more or less assured survival and a chance at reproduction. At least, until humans arrived.

When Alroy ran the simulations for North America, he found that even a very small initial population of humans—a hundred or so individuals—could, over the course of a millennium or two, multiply sufficiently to account for pretty much all of the extinctions on the record. This was the case even when the people were assumed to be only fair-to-middling hunters. All they had to do was pick off a mammoth or a giant ground sloth every so often, when the opportunity arose, and keep this up for several centuries. This would have been enough to drive the population of slow-reproducing species first into decline and then, eventually, all the way down to zero.

Kolbert, The Sixth Extinction, page 234

The humans responsible for these extinctions may never have even noticed what they had done.

For people involved in it, the decline of the megafauna would have been so slow as to be imperceptible. They would have had no way of knowing that centuries earlier, mammoths and diprotodons had been much more common. Alroy has described the megafauna extinction as a “geologically instantaneous ecological catastrophe too gradual to be perceived by the people who unleashed it.” It demonstrates, he has written, that humans are capable of driving virtually any large mammal species extinct, even though they are also capable of going to great lengths to guarantee that they do not.”

Kolbert, The Sixth Extinction, page 234

And that “geologically instantaneous catastrophe too gradual to be perceived” not only affects our perception of large mammals, but many other species as well:

Three biologists concluded…that biomass—the total weight of living things—off North America’s east coast may have declined by 97 percent since written records began. The failure of coastal residents and scientists to recognize such a shocking diminution seemed to Pauly explainable only by a long-term pattern of amnesia. Each generation of people saw the coast they grew up on as the normal state of nature and measured the declines of sea life against that baseline. With every new generation, the baseline shifted—“a gradual accommodation of the creeping disappearance,” Pauly said. We are forgetting what the world used to look like.

MacKinnon, The Once and Future World, page 19

Presumably, this is exactly what the written record ought to have prevented. By extending memory beyond our own lifespans, writing promises to help us understand time and knowledge on a longer scale. Alas, it seems more often than not the frailties of the human mind exceed our efforts to improve it.

When the people of Mao County, in central China, killed off the last of their bees via pesticides and overuse, they turned to alternative methods to pollinate their apple trees: people. Laborers dipped “pollen from blossom to blossom using brushes made from chopsticks and chicken feathers and cigarette filters.” MacKinnon continues:

Fifteen years later, three American researchers published an economic analysis of what they called “the parable of the bees,” and turned that story upside down. Mao County’s apple growers told interviewers 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 labor 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 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.”

MacKinnon, The Once and Future World, page 140

In other words: judging something solely by its economic value is foolhardy. Schumacher, writing nearly forty years earlier in Small Is Beautiful, outlines this more directly:

I am asking what it means, what sort of meaning the method of economics actually produces. And the answer to this question cannot be in doubt: something is uneconomic when it fails to earn an adequate profit in terms of money. The method of economics does not, and cannot, produce any other meaning. Numerous attempts have been made to obscure this fact, and they have caused a great deal of confusion; but the fact remains. Society, or a group or an individual within society, may decide to hang on to an activity or an asset for non-economic reasons—social, aesthetic, moral, or political—but this does in no way alter its uneconomic character. The judgement of economics, in other words, is an extremely fragmentary judgement; out of the larger number of aspects which in real life have to be seen and judged together before a decision can be taken, economics supplies only one—whether a thing yields a money profit to those who undertake it or not.

Schumacher, Small Is Beautiful, page 44

My, but how quickly we forget this. The prevailing storyline these days would have you believe that valuations and profit margins represent the complete and singular picture of a business’ worth. No other metric figures into the conversation. Schumacher, again:

Economics, moreover, deals with goods in accordance with their market value and not in accordance with what they really are. The same rules and criteria applied to primary goods, which man has to win from nature, and secondary goods, which presuppose the existence of primary goods and are manufactured from them. All goods are treated the same, because the point of view is fundamentally that of private profit-making, and this means that it is inherent in the methodology of economics to ignore man’s dependence on the natural world.

Schumacher, Small Is Beautiful, page 46

I’ve long thought (though I’m aware just how unlikely this is) that economics, as a discipline, ought to be kicked down a notch or two. We treat it, in our ordinary political conversations, as if it were all that mattered, or at least as if it mattered more than many other things. The subtitle to Small Is Beautiful—“Economics as if People Mattered”—remains an aspiration.

In The Once and Future World, MacKinnon describes growing up in a nameless prairie, and his first memories of nature. As a boy, he would sometimes spot a red fox pouncing on its prey, and fox dens abounded. But when he investigates this childhood vision, he learns that the red fox arrived on the prairie not long before he did: it’s an invasive species, brought to North America by British colonists nostalgic for hometown fox hunts. Lacking predators, the fox expanded aggressively, and now poses a threat to many native species. What he imagined as “nature” was in fact the consequence of human intervention.

[If] I took you onto the remaining grasslands around my hometown today, they would seem to you as ancient and unchanging as anywhere on earth. You’d smell sage and the vanilla scent of ponderosa pine bark, and you’d hear meadowlarks, and the bunchgrass would rustle like the restless dead. Cicadas would zing in swales of aspen, and if you were lucky with the year and the season, the brittle prickly pear would be in lemon-yellow bloom. The breeze would suck across the hilltop balds where it has carried away the soil and leave you blinking as it dried your windward eye. In the dust you might see stripes where gopher snakes had lain to warm themselves in the morning sun. You might see an ant lion spitting sand as it tries to knock insects into its pit trap. You might see fox tracks. The whole of the landscape, from sky to soil, would have the look and smell and feel of what we call nature. It is an illusion that has in many ways created our world.

MacKinnon, The Once and Future World, page 16

Letting go of that illusion is, according to MacKinnon, critical to forging a smarter and more sustainable relationship with the world. We’ve irreversibly changed nature, and we’re going to continue to do so; but that change needn’t be destructive.

[On] the day before I left for a colder and more landward place, I took one final swim—just a way of saying farewell to a new friend. I was wading ashore, already feeling nostalgic, when some creature lashed out from the sand, stung my ankle, and then zigzagged off into the murk. Nature may not be what it was, no, but it isn’t simply gone. It’s waiting.

MacKinnon, The Once and Future World, page 87