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Human success at the expense of other species is “a pretty awful legacy”

October 19, 2017

“People compare it to burning down a library. That’s what we’re doing, just eliminating a certain knowledge of how to make it in this world.  But because those are such alien ways, you just don’t even know how other species make a living. Until something goes really radically awry, we don’t even notice it. And things are going radically awry often, and we don’t even notice it.”


A classic XKCD comic showing that humans and their domestic animals are, ah, decisively winning the mammal race.  (XKCD)

Interview by David Roberts on, 12 Oct 2017.  Author Elizabeth Kolbert challenges us to see human history through the eyes of other animals.  Kolbert starts in reference to Paul Crutzen’s work.  Crutzen is part of the Pontifical Academy of Sciences and has been talking about climate change and the Anthropocene — the extent to which we humans are changing the earth — for some time.

Last year, the Nation Institute launched a Jonathan Schell Memorial Lecture Series, in honor of the late environmental journalist. The topic is rather grandiose: The Fate of the Earth.

The first lecture, last year, was given by famed environmental writer and activist Bill McKibben, who spoke about climate change.

This year, the lecture was delivered Wednesday by Elizabeth Kolbert, a New Yorker staff writer and the author of several books, including 2014’s Pulitzer-winning The Sixth Extinction: An Unnatural History.

Kolbert’s lecture took on a larger and, if anything, even more difficult subject, namely what the Anthropocene — the geological age of human influence — is like from the perspective of other species. As humans have grown and spread, they have jammed unfamiliar animals and pathogens together in the geological blink of an eye, driving countless species to extinction. In the 3.8 billion-year history of life on this planet, she says, “no creature has ever changed the earth at the rate that we are changing it right now.”

As usual, Kolbert’s message is bracing and free of false-hope homilies. You can watch a video of the lecture here.

Kolbert is something of a hero of mine. Her 2006 Field Notes From a Catastrophe was the first book on climate change I ever read, and its concluding line still haunts me: “It may seem impossible to imagine that a technologically advanced society could choose, in essence, to destroy itself, but that is what we are now in the process of doing.”

So it was a pleasure to chat with her by phone about the issues and difficult moral dilemmas her lecture raises — perspectives too often absent from our typically human-centric discussions of environmental damage. Our conversation has been edited for length and clarity.


“Toughie,” the world’s last known Rabbs’ fringe-limbed tree frog, died in 2016. Are we guilty of murder?  (Wikipedia)

David Roberts

Why did you choose to focus on biodiversity? Is it just because Bill McKibben took climate change already?

Elizabeth Kolbert

[laughs] Well, you know, I don’t want to downplay that. But at the same time, I have come to see — and this was the impetus for writing The Sixth Extinction — that climate change is part of an even bigger issue. So when the topic is the Fate of the Earth, it seemed like you could open it up into this even bigger issue, the way we are changing the planet, for all intents and purposes, permanently. As I say, unfortunately, climate change is just one of those ways, and not even necessarily the most significant.

David Roberts

Climate change is such a huge issue, it’s already difficult for people to fit it in their heads. To put it into an even bigger context … how do you even go about that? Do you feel like you’ve successfully gotten your head around it?

Elizabeth Kolbert

I don’t think anyone does, really. The reason the Anthropocene as a concept really took off since Paul Crutzen first proposed it — which is not very long ago — is that it gives us a framework for thinking about a lot of things that seem disparate but are all pointing in one direction. To look at it in geological terms has been a really interesting and useful exercise.

I’ve been out in the field with people who are trying to look at human impact on the planet in terms of the great history of life — half a billion years of multicellular life. How is this going to look millions of years from now? When you go through that exercise, it tends to wash away everything that we humans are attached to and leaves just these geochemical markers, basically.

You find that, wow, what humans are doing is really significant. It’s significant on the scale of the history of life. It kills your worldview, I think.

David Roberts

One way people have tried to narrow this, to make it manageable, is to frame the benefits of biodiversity in human terms — “ecosystem services” and what they do for us. What do you think of that tactic?

Elizabeth Kolbert

I totally understand it and sympathize with it. And I think there’s a very compelling case to be made that, however independent we think we are from biological systems and geochemical systems, we’re very clearly not. All of our oxygen is biologically produced. We’re still intimately connected — even those of us who live in a high-rise in Manhattan — to this world, even though we may not appreciate that.

So you mess around with these systems, you push them too far, and it’s going to come back and bite humanity in the ass. I think that’s true.

But I also think it’s true that, taking the broadest possible view, humans are just one of many, many species that have lived on Earth. So even if we decided it is possible for us to escape unscathed through a mass extinction, the idea that we would eliminate many of the other species on Earth, including our closest relatives (we’re in the process of eliminating the great ape), is a pretty awful legacy.


A gorilla, one of many Hominidae (great ape) species humans are crowding out.  (Wikipedia)

David Roberts

When we drive a species to extinction, is that like murder?

Elizabeth Kolbert


David Roberts

We assess people’s actions in terms of intentionality and responsibility, but we don’t assess “natural processes” that way. We don’t think poorly of a lion for killing a gazelle. What special obligations do humans have to other species?

Elizabeth Kolbert

I don’t have a straightforward answer to that. It turns out that our ethics are based on humans and human consciousness, so when we look at other species, we often try to do it in terms of consciousness. Are they consciously suffering or not? There’s a lot of talk of ethical treatment of animals, for example, in the context of farming.

But is there ethical treatment of animals in the context of just the world? Nature, red in tooth and claw; everything is competing for existence. It’s not even clear to me if it’s possible to have what we as humans would identify as an ethical system that would tell us what the right thing to do [in the Anthropocene] is.

That being said, I don’t think that absence lets us off the hook.

David Roberts

I’ve certainly heard the perspective expressed that morals are just for other humans. Like, if we travel around the world in our ships and the accidental byproduct is that some frog goes extinct, that’s just how nature works. It has no moral valence.

Elizabeth Kolbert

On one hand, these are such big issues that they’re hard to talk about, but on the other hand, we are so powerless. Yes, people move around the world. Many, many species of amphibians are gone, purely accidentally — to this day, we don’t know who or how exactly those moved around.

As you say, intentionality is very, very difficult to parse now. That’s also true in these cases of pathogens moving around. But there are lots of things along the way between poaching an elephant — which is also a huge, huge problem right now, simply killing things for their tusks or their horns or whatever — and accidentally moving a pathogen around.

But what I’m really trying to point to is just the incommensurability of the way we like to think of our actions and the way they’re playing out in the world. I don’t exactly have a takeaway there. It’s more a negative message. It’s more, let’s not be smug about our ethics.

We can all agree that we have these human ethics, toward other humans, that we’re not observing; that’s step number one. But even if we were observing them and we were simultaneously doing in the rest of the biosphere … that should still give us pause.

David Roberts

Where do your moral and ethical principles come from? Are you religious? Or [do you] have some sort of philosophy on these matters?

Elizabeth Kolbert

No. I have some personal — I don’t know if I want to call them heroes — people whose work I have been inspired by, but they’re not a tradition. I’d say it’s ad hoc. I would not claim to have a systematic view of the world.

David Roberts

One thing you run into when you discuss these kinds of things is you say, “We shouldn’t drive this frog species extinct,” and someone asks, “Why?” You say, “Seems bad.” Pretty quickly your ethics ground out in raw instincts.

Elizabeth Kolbert

Yes, I agree.

First of all, it’s an area where ethics and aesthetics and science come together. And because we’re dealing with a world that we only very, very partially understand, it’s very difficult to answer these questions.

But the other thing is that the more you try to get at the answers, the more you realize we are often blocked from seeing the impact of our actions. You can’t even anticipate them. We’re just humans, this one species that has a certain way of making our living. All around us are other answers to the question, “How do you survive on this planet?”

People compare it to burning down a library. That’s what we’re doing, just eliminating a certain knowledge of how to make it in this world.

But because those are such alien ways, you just don’t even know how other species make a living. Until something goes really radically awry, we don’t even notice it. And things are going radically awry often, and we don’t even notice it.

David Roberts

Charles C. Mann, the author, thinks we are no different than protozoa — absent natural limits and predators, we’re going to breed and breed and overbreed and crash. Do you see any realistic hope for our species asserting self-aware control over that primal biological force?

Elizabeth Kolbert

There’s a lot to unpack there.

First of all, the question of how many people can the world support. Predictions are that eventually, toward the end of this century, if certain demographic trends continue, that world population will peak around 10 billion people. Now, whether we can get through that and then bring the population down and have a happy, healthy, prosperous world — that’s pretty much beyond my pay grade.  Anyone who thinks they can tell you that is full of shit. We just don’t know.

But what I am trying to point out is the flip side of that, which is, okay, it’s true we have defied all these expectations, right? When Malthus was writing, there were roughly a billion people on the planet; now, there’s 7.5 billion people. So he was clearly, massively wrong.

But while we’ve increased our numbers, it has been at the expense of other things. We are simply consuming other species. We are consuming a tremendous amount of the primary productivity of the oceans, for example, just emptying them out.

And so there’s two questions really, it seems to me. One is will humanity make it through this basically unrestrained growth, both in terms of numbers and in how much we as individuals consume? And meanwhile, what happens to everything else?

The answer is not necessarily the same. I mean, humanity has found that it can reproduce and consume at a very rapid rate and, depending on how you look at it, the world continues apace — though obviously many people are not doing well, many people are.

But most other species are not doing too well.

Not doing well at all.  (Science Advances)

David Roberts

One thing I always appreciated about your writing is your tragic imagination. I feel like lots of folks in the climate discussion lack that. [When author David Wallace-Wells wrote a story on the tragic potential of climate change, he was roundly scolded by the climate positivity police.]

Elizabeth Kolbert

I really appreciate that. Thank you.

David Roberts

American culture, in particular, lacks a tragic imagination — an ability to imagine that things can go horribly wrong.

Elizabeth Kolbert

I completely agree with you. That’s the only way we can explain what’s going on right now.

A couple years ago, we lived in Rome for a year. In Rome, you are surrounded by the ruins of a civilization. You don’t have the same our-best-days-are-ahead-of-us nonsense.

Is humanity smarter than a protozoan?   in, 

So, how’s humanity doing?  Good question. One way of answering is to look at global per-capita GDP — that is, the average amount of economic activity per person in the world. From that perspective, humanity is doing well:

WikipediaClick to enlarge

We’re getting richer!

Here’s the thing, though: While GDP has come to serve as a stand-in for human welfare, it was not originally developed for that purpose. What’s more, it performs poorly for that purpose. Objections to GDP as a measure of human welfare are as old as GDP itself; I’ve written about them before. It doesn’t distinguish between welfare-enhancing economic activity and the welfare-degrading kind. It doesn’t value natural capital. It doesn’t incorporate life satisfaction or economic inequality. And so on. Any true measure of human welfare should be far more nuanced.

So what to use instead? One alternative measure is the Genuine Progress Indicator, or GPI, an attempt to combine personal consumption expenditures (what GDP captures) with a few dozen other positive and negative indicators, including crime, pollution, inequality, the loss of ecosystem services, the value of domestic labor, self-reported happiness, and so forth.

(There is a long, involved, and contentious literature on GPI and other alternative metrics. Needless to say, no aggregate measure of welfare is precise; all reflect their own contestable assumptions; all have their shortcomings. But it seems to me that almost any of them, including GPI, are preferable to simple GDP, which after all includes contestable assumptions of its own.)

In a new paper in the journal Ecological Economics, a team of researchers attempts something novel: to aggregate all the available GPI data in various countries into a global per-capita GPI.

Their top-line finding is pretty astonishing: Global per-capita GPI peaked in 1978 and has declined since. Put another way: Some time around 1978, the rise in aggregate global economic activity ceased enhancing global economic welfare — GDP and GPI parted ways.

Click to embiggen.
Ecological Economics Click to enlarge.

Why do they split? The critical difference between the two is that GPI incorporates the spending down of natural capital as an economic cost — it’s no coincidence, the authors note, that 1978 is also about when “global Ecological Footprint exceeded global Biocapacity” for the first time.

What’s more, the researchers found that GDP/capita and GPI/capita rose together until the former hit about $7,000; at that point, GPI stops rising alongside it:

Click to embiggen.
Ecological Economics Click to enlarge

It’s important to be careful with conclusions here. It’s not necessarily that making more money than $7,000 makes people less happy. I know I’d be happier with $700,000 than $7,000. Rather, at that level of global economic growth, the cumulative cost of negative indicators like lost natural capital, inequality, and pollution start to cancel out the welfare gains of growth.

Just as a thought experiment, let’s say we capped global per-capita GDP at $7,000 (none of us reading this would like that much, I suspect) and total global GDP at its current level, $67 trillion. How many people could the earth support at that level? “No more than 9.6 billion” (for reference, we are at 7.1 billion, headed to 9.6 billion by 2050, so it’ll be a tight fit). The authors note, rather wryly I thought, that to reach this exalted state, “variations in income would need to exist between and within nations, however these disparities should be much smaller than they are today.” Yes. Much.

This is the radically egalitarian message of this kind of research: maximizing global economic welfare from this point forward will involve more redistribution than growth. The simple, headlong, unequal growth on the 20th century is no longer working.

Of course each country has it’s own GDP/GPI story to tell. There’s lots of good stuff in the paper about individual countries, and also how GPI stacks up against other indicators like ecological footprint, the Human Development Index, life satisfaction, the Gini coefficient, and so on. Dig in if you like that kind of stuff.


By way of discussion, it’s worth noting that this paper’s results tack somewhat against a good bit of current research showing that the correlation between rising income and rising happiness holds pretty much forever, though it loses strength higher up. This is the new hip stance in these matters: “Yes, money really can buy happiness.” (Or put another way: that there may be no Easterlin Paradox.)

What explains the disparity? Can we increase our welfare by growing more, or can’t we? Again, I think the key difference is that GPI is scoring the loss of natural capital as a cost. As the authors put it:

Economic activity, it should be recognized, is undertaken to generate a level of economic welfare greater than what can be provided by natural capital alone. For the GPI to properly reflect this reality, it is necessary to subtract the permanent loss of natural capital services.

This explains the apparent contradiction. As finite resources are consumed, the welfare (and happiness) of current people rises, while the natural capital necessary to sustain economic activity declines. GDP will only pick up on the former; GPI incorporates the latter.

It ends up, as so many things do, coming down to how much value one places on the welfare of future generations. Is the “humanity” whose welfare we are attempting to maximize currently alive humans, or the species in its whole great arc on this planet?

To some folks, the unsustainability of running faster and faster through finite resources seems self-evident. Others, however, hate this sort of thinking. They believe that market forces will push human beings to discover new or more sustainable natural resources, or squeeze more out of current ones (as we are doing now with oil). They believe that economic growth, not necessarily defined as material throughput but simply as increases in welfare brought about by mutual trade, has no limit because human ingenuity has no limit. There is no petri dish for humanity — or rather, there’s no reason our petri dish can’t go on expanding, forever. Man Will Overcome.

The way I think about the question is: Are we a biological species or an economic species? Set aside an hour or two some day and read Charles C. Mann’s magnificent “State of the Species.” It frames the question in the clearest possible terms.

It would be no surprise at all for a biological species to expand its population into overshoot, destroy its habitat, and go extinct. It’s what you would expect of an organism with few competitors. Mann discusses the work of scientist Georgii Gause, working in the 1920s. Gause’s original experiment was simple but brilliant: five test tubes, each with a few drops of broth, each containing five single-celled protozoans of a single species. After a week’s observations, here’s what he found:

What Gause saw in his test tubes is often depicted in a graph, time on the horizontal axis, the number of protozoa on the vertical. The line on the graph is a distorted bell curve, with its left side twisted and stretched into a kind of flattened S. At first the number of protozoans grows slowly, and the graph line slowly ascends to the right. But then the line hits an inflection point, and suddenly rockets upward—a frenzy of exponential growth. [See: global GDP graph at the top of this post.] The mad rise continues until the organism begins to run out of food, at which point there is a second inflection point, and the growth curve levels off again as bacteria begin to die. Eventually the line descends, and the population falls toward zero.

In nature, as Darwin so perspicaciously noted, natural selection keeps this process in check. Organisms have competitors and limited ecosystems. But in a petri dish or test tube, free of competitors, a species will race to the limit and shoot past it. It is the nature of life, to propagate itself. Mann writes:

By luck or superior adaptation, a few species manage to escape their limits, at least for a while. Nature’s success stories, they are like Gause’s protozoans; the world is their petri dish. Their populations grow exponentially; they take over large areas, overwhelming their environment as if no force opposed them. Then they annihilate themselves, drowning in their own wastes or starving from lack of food.

In short, a biological species as dominant as ours, largely free of competitors and still with large stocks of natural capital to burn through, should be expected to hit limits and suffer catastrophes. And it won’t be pretty:

If we follow Gause’s pattern, growth will continue at a delirious speed until we hit the second inflection point. At that time we will have exhausted the resources of the global petri dish, or effectively made the atmosphere toxic with our carbon-dioxide waste, or both. After that, human life will be, briefly, a Hobbesian nightmare, the living overwhelmed by the dead. When the king falls, so do his minions; it is possible that our fall might also take down most mammals and many plants. Possibly sooner, quite likely later, in this scenario, the earth will again be a choir of bacteria, fungi, and insects, as it has been through most of its history.


However. If we are an economic species — a welfare-maximizing species, a rational species — we will look ahead, anticipate problems, and innovate solutions. We will decouple economic growth from material throughput and grow without limit, eventually into space, bounded only by our own imaginations. “To seek out new life and new civilizations / To boldly go where no man has gone before.”

So which is it, collapse or transcendence? Kunstler or Kurzweil?

I’ll admit to being somewhat schizophrenic on this question. I’m very much attracted to the notion of boundless ingenuity. But the raw truth is that we are not, in fact, looking ahead, anticipating problems, and innovating solutions — not on a broad scale. We are not taking the kind of drastic action necessary to shift to long-term sustainability. In fact, it’s proving difficult for us even to talk about it sensibly or govern in the right direction. Mann again:

Not only is the task daunting, it’s strange. In the name of nature, we are asking human beings to do something deeply unnatural, something no other species has ever done or could ever do: constrain its own growth (at least in some ways). Zebra mussels in the Great Lakes, brown tree snakes in Guam, water hyacinth in African rivers, gypsy moths in the northeastern U.S., rabbits in Australia, Burmese pythons in Florida—all these successful species have overrun their environments, heedlessly wiping out other creatures. Like Gause’s protozoans, they are racing to find the edges of their petri dish. Not one has voluntarily turned back. Now we are asking Homo sapiens to fence itself in.

What a peculiar thing to ask! Economists like to talk about the “discount rate,” which is their term for preferring a bird in hand today over two in the bush tomorrow. The term sums up part of our human nature as well. Evolving in small, constantly moving bands, we are as hard-wired to focus on the immediate and local over the long-term and faraway as we are to prefer parklike savannas to deep dark forests. Thus, we care more about the broken stoplight up the street today than conditions next year in Croatia, Cambodia, or the Congo. Rightly so, evolutionists point out: Americans are far more likely to be killed at that stoplight today than in the Congo next year. Yet here we are asking governments to focus on potential planetary boundaries that may not be reached for decades. Given the discount rate, nothing could be more understandable than the U.S. Congress’s failure to grapple with, say, climate change. From this perspective, is there any reason to imagine that Homo sapiens, unlike mussels, snakes, and moths, can exempt itself from the natural fate of all successful species?

In his conclusion, Mann compares what’s necessary to a species-wide form of what the Japanese call hara hachi bu: “belly 80 percent full.” The brain receives the body’s signal of satiety long after it is sent; during its transmission, we eat to excess. So the way to stay healthy, to eat the appropriate amount, is to stop eating before feeling entirely full. One way of looking at these new results on GPI is that they are an early indicator: we are hara hachi bu. We have enough, if we would share it more equitably. But GDP shows that we’re still eating furiously.

Can a successful species stop before it is stuffed and sick? It’s never been done before, but humans have done lots of things that have never been done before. Maybe human intellect and imagination are something truly new in the world. After all, concludes Mann …

… it is terrible to suppose that we could get so many other things right and get this one wrong. To have the imagination to see our potential end, but not have the imagination to avoid it. To send humankind to the moon but fail to pay attention to the earth. To have the potential but to be unable to use it—to be, in the end, no different from the protozoa in the petri dish.