Do People Need Biodiversity? It’s Complicated.
Until about 15,000 years ago, Earth was home to a menagerie of now-fantastical creatures: giant kangaroos and truck-sized sloths, woolly rhinoceros and aurochs so large as to make bison look cuddly. But as the planet warmed and our own ancestors proliferated, most of these enormous beasts disappeared. Their legacy survives in museum dioramas and fairy tales — and, perhaps, in less-obvious ways.
After those animals went extinct, something strange appears in the fossil record, again and again, around much of the terrestrial world: a layer of ash. It doesn’t seem to be a coincidence. According to some scientists, the sudden absence of big plant-eating animals made Earth’s landscapes more fire-prone.
This is still just a theory, but the proposed links between big plant-eaters and fire are compelling. Those animals, say the scientists, consumed fire-fueling woody debris; they grazed in patterns that created natural firebreaks and, by rooting through the earth, buried plant material that might otherwise have become tinder. And if giant sloths are now just a memory, the big plant-eaters who remain — elephants and musk ox, moose and wildebeest and so on — still influence fire dynamics. Protecting them could be a sensible fire prevention strategy.
In November I blogged about this for Anthropocene magazine. A few days later, Linus Blomqvist at The Breakthrough Institute wrote “Does wildlife loss threaten civilization?,” a critique of the oft-repeated argument that extinctions and extirpations are tragic not only because something immeasurably special is lost, but because human well-being is affected too.
Blomqvist quoted the World Wildlife Fund’s recent Living Planet Report, which described wild animal populations declining by an average of 60 percent in just the last several decades. “Our health, food and security depend on biodiversity,” proclaimed the report. (Its language echoed that used by Conservation International: “Our food, our water, our livelihoods — they all come from nature.”) Mike Barrett, one of that study’s co-authors, told The Guardian newspaper that wildlife declines are “actually now jeopardising the future of people. Nature is not ‘nice to have’ — it is our life support system.”
To Blomqvist, this is a generalization without much evidence to support it. “Framing the loss of wild species as a threat to human civilization and material well-being,” he wrote, “is a questionable proposition.” In many ways I agree with him.
At precisely the same time as wild lives are imperiled and dwindling, billions of people are enjoying historically-unprecedented prosperity and health. Which isn’t to say that economic well-being flows from nature’s destruction, or that future well-being requires it — that’s absolutely not the case — but simply that extinctions and extirpations have not precluded human flourishing.
Moreover, there’s a lot of conceptual fuzziness and arguable hand-waving in this people-need-nature rhetoric. It implicitly equates nature with biological richness and abundance, but much of what the biosphere provides — clean air, clean water, fertile soil — can be derived from stripped-down ecosystems. Tree plantations still absorb carbon dioxide and exude oxygen; defaunated wetlands still filter water and buffer against storms; and most of the food we eat comes from low-biodiversity systems.
Human ingenuity can also substitute for nature’s “services.” The results might be unpleasant in many ways — I’d much rather rely on bats and earthworms than pesticides and fertilizers — but they’re rarely an existential threat to human societies. The vast, fertilizer-fueled Gulf of Mexico dead zone is a horrible, shameful thing, and has inflicted hardship and suffering on many people, but southeastern coastal communities have not collapsed because of it.
And while some people, such as those who work in small- and large-scale fisheries, depend directly on “nature,” many do not. One of the great economic and conservation challenges of our time is how to disentangle prosperity and economic well-being from resource consumption. Claiming that “all our economic activity ultimately depends on nature,” as does Conservation International, normalizes a biosphere-impoverishing state of affairs and constrains our ability to imagine other ways of thriving.
To argue that a nature-rich Earth will require most people to disentangle economic growth from resource consumption while accomodating a few traditional-use cultures isn’t nearly so motivating as “everything that has built modern human society is provided by nature,” but it’s much closer to the truth.
All of which is uncomfortable to say. Conservation, the task of protecting nonhuman life on a human-dominated Earth, desperately needs help. But I worry that generalizations and dogma could do more harm than good. What if they backfire? What happens when the last northern white rhinoceros dies and nothing changes? Can anyone really argue with a straight face that we’d be healthier and wealthier if Steller’s sea cows and ivory-billed woodpeckers still existed?
It’s far better, I think, to argue that all these beings deserve to flourish simply because they’re wonderful. Because they’re alive and each lineage, each life, is valuable and good and deserves to be.
That said: If in specific instances our own well-being intersects with nature’s, then by all means embrace it. Which brings us back to the notion that big plant-eating animals make landscapes less fire-prone. The study I covered was part of an entire journal issue devoted to scientists considering the benefits of rewilding landscapes with lost animals, or at least their living relatives.
In addition to regulating fire, those animals might also fight climate change by helping ecosystems sequester more carbon; reduce the impact of invasive species; fertilize streamside forests; enrich soils; and regulate unpredictable ecological responses to climate change. And though it wasn’t covered in these studies, one could also add biodiversity’s disease-regulating effects. Biologically rich communities appear to slow the evolution of extremely dangerous pathogens and minimize the spread of what pathogens do exist.
All this would make Earth more hospitable. More lovely. It’s also instructive to think about what benefits we might now take for granted: the seed-dispersing activities of squirrels and jays, for example, or the soil-aerating habits of skunks and moles. Humanity would probably still flourish on an Earth with few wild animals — we’re nothing if not adaptable — but it would be a barren and squalid place.
Which would seem to contradict the earlier critique of people-need-nature claims. Still: rather than sweeping generalizations about people needing nature to survive, why not argue that a biologically richer Earth is simply far nicer? Far more hospitable, perhaps more peaceful? It’s not so apocalyptic, but I think it’s more accurate, and maybe it would be more effective, too.
