Book Review: The Sixth Extinction

My copy of the book.

We’re all going to die, or maybe not (well, yes, we still will). At the macro level, which is to say, on the geological and even cosmic timescale, human ingenuity animates both our existential salvation and destruction, that which has allowed us to evolve as a species to pontificate about our own survival (and that of other species!) and the ability to hit the self-destruct button en masse, perhaps not even intentionally (think an accident with the handling of nuclear weapons). Or to put a finer point on the issue of our time and that of our descendants: We are currently in the Sixth Extinction, following from the Big Five, with the most famous being the asteroid impact that wiped out the dinosaurs more than 65 million years ago (incidentally, allowing us to rise up). That may seem odd at first blush. After all, as far as I know, an asteroid six miles across hasn’t impacted Earth, nor did a volcano erupt to epic proportions to acidify the oceans and pour ash everywhere. But that is the thesis of The New Yorker’s science journalist, Elizabeth Kolbert’s, 2014 Pulitzer Prize-winning book, The Sixth Extinction: An Unnatural History. I will say up front, Kolbert’s book is exceedingly readable and accessible (I finished it largely in one sitting this morning/afternoon), as any good book about science ought to be, and also, her prose is charming, engaging, funny, and conveys the importance of the subject without being too forcefully on the nose. In other words, you don’t need to be a paleontologist (someone who studies fossil animals and plants), herpetologist (someone who studies amphibians and reptiles), climatologist, or anything else, as I’m not, to understand Kolbert’s book. For that reason, it’s among my favorite nonfiction reads of the year thus far.

To go back to my opening salvo: We’re all going to die, and yet, this clear fact eluded science and scientists for centuries. Which is to say, science largely busied itself with how life emerged, evolved, and all its constituent chemical, mathematical, and physics parts and such and so forth. But never the fact of dying, i.e., whether a species could die out and cease to exist. That thought process, and then the fossilized evidence to support it, didn’t start permeating the scientific space — and it resulted in refutations and/or subsuming it into the existing belief in a deity-as-creator — until relatively recent around the time of the French Revolution and a status quo-busting Frenchman. Even when Darwin and others helped to get the ball rolling, there was still resistant to, and an ingrained incredulity that life could be going along and then suddenly, some cataclysm intervened to wipe out life, or much of it. The aforementioned asteroid impact theory wasn’t postulated until 1980 (and again, was widely criticized!), with more definitive evidence coming within my own lifetime. So, interestingly, while we are within this Sixth Extinction event, Kolbert argues, we’re also still figuring out our past.

The gist of Kolbert’s thesis is that humans from our inception are a migrating species, and as such, we bring with us non-native, that is, invasive, species with us to new parts of the globe altering the existing biosphere. Obviously, we are also invasive, too! Our migratory patterns impacted “large Mammalia,” as well, which seems counterintuitive at first owing to their size. I’ve always wondered this, too: Why are there, for the most part, not any large animals anymore? And the ones who are still around, why are their numbers diminishing? You know that joke in history circles about how if you don’t know the answer just say “George Washington” and you might be right? I think in natural history circles, the go-to answer could be “humans” and you wouldn’t be wrong most of the time. As Kolbert explains, when humans arrived, “the rules of the survival game” changed. Whatever allowed an animal to adapt and survive via natural selection — natural selection selecting for the genes that would ensure a species’ progeny line would continue into the next generation — can’t possibly account for something on the scale of a mass extinction. That is, it’s not like the dinosaurs or other life on Earth wiped out by the asteroid did something “wrong” evolutionarily speaking. The same was true of the “large Mammalia” going extinct. Yes, they’re large, and that largeness ensured they had no natural predators for a long time, and that also meant, importantly, their slow reproduction cycles weren’t a hinderance to ensuring their progeny line continued on into the next generation. Then, along come humans, who can make prey of anything, including large Mammalia, and it doesn’t have to be in great numbers — just enough to ensure the progeny line couldn’t keep up — and you guaranteed extinctions of various “large Mammalia.”

Now, take that fact of human existence, and add the Industrial Revolution, which not only magnified human migratory patterns to every part of the globe and set the stage for globalism (ensuring more mixing of non-native and native species), but also, and this is a keyword in Kolbert’s book, exponentially increased the rate of how fast things were moving, so much so that species we encountered, big and small, plants and amphibians, couldn’t possibly keep up and reconstitute their progeny lines. And even if they tried to migrate, too, to avoid our interference, they ran into our cities and roads, only further ensuring their extinction. Those species that have been able to adapt to our rate of impact and migrate safely are surviving.

Or, of course, the species we purposefully elect to save, or try to save, via a plethora of conservation societies, efforts of scientists, and zoos, including my city’s zoo, the Cincinnati Zoo, which had an entire chapter devoted to the Zoo’s efforts to save the Sumatran rhinos (through insemination). Because again, humans have that double-edged sword of ingenuity, and I would add, that of the Industrial Revolution, i.e., the richer we get, the more developed we get, the better willing and able we are to be “stewards of the Earth” and other species and plant life. But the breadth of any biodiversity rescue effort operation is a.) how do you determine which species to save, and account for unforeseen negative consequences doing so might have? and b.) there are nearly 1 million different insect species; we can’t save them all! They can’t all exist frozen in vials at the Cincinnati Zoo (which I didn’t know they did that).

What this “mass extinction” effect means is that we are both creating a New Pangea, as it were, by making the world smaller with our migratory patterns and globalization, and ensuring because of it that there is less biodiversity. And certainly, perhaps, threatening our own survival because despite thinking we are above or outside of nature, we depend on that biosphere and biodiversity. On a granular level separate from humans, the Great Barrier Reef Kolbert talks about shows how much life depends on that “structure,” as it were, or look at army ants. Ants are incredible, but also terrifying when you see them magnified. Kolbert explains that there’s an entire class of birds known as obligate ant-followers that follow the army ants (who devour 30,000 prey during their marches!), eating insects the ants have flushed out, or the butterflies that feed on the birds’ droppings, and parasitic flies that deposit their young on startled crickets and cockroaches, or the mites that hitch rides on the ants. Phew, that’s just the start! More than 300 species live in association with the ants. Ants! Imagine, then, how many are depending upon the Great Barrier Reef, which might not be around much longer (within my lifetime). We know this intuitively from a human-to-human level, too, how interdependent we are on so many other people, many of whom are strangers to us (thank you, Adam Smith!). The same applies with other species and plants.

Life is a teeming, beautiful mosaic of ordered chaos, and not unfortunately because I mean, I’m not anti-human, but it is a fact that nature also birthed a species, us, that threatens that order, which is extraordinary on a metaphysical level. I suppose nature birthed asteroids and volcanoes as well though. (You can see I’m thinking through these issues in real time as I write this review!)

My only slight confusion with Kolbert’s point is how our arrival as a species and the rate increase brought upon by the Industrial Revolution tantamount to one of the Big Five mass extinction events? Thinking through it as a layman, those Big Five were like a house party, where diverse life was teeming along in a house, well-adapted to the environment of the house, and then through no fault of anyone in that house, a house-sized piano dropped from the sky on the house, killing everyone. Eventually, a new strain of life will evolve and develop, but what existed in that house is largely gone, with maybe some cockroaches surviving, however (as not all life was eliminated by the asteroid, for example). The emergence and development, rapidly relatively speaking, of humans, feels the same way in terms of the aforementioned issue with “large Mammalia,” but not with a sudden cataclysm. Maybe if I think about it, as perhaps Kolbert intended and implied, on a geological timescale? Dinosaurs still took another 33,000 years to die off after the asteroid hit, which in human years, is hard to imagine, but in geological time, represents a blip and meets the parameters of “sudden.”

That digression aside, I thought Kolbert starting with the golden frogs in Panama set the tone of the book well because frogs are cute, but more importantly, Kolbert quickly contextualized how fast everything has changed with the golden frogs and amphibians broadly (and also our efforts to save them, nonetheless). For example, Kolbert explains, it used to be that amphibian species lasted much longer than mammals; you’d expect to see one of them go extinct every thousand years. That effectively means from a human timescale perspective, no human should witness an amphibian extinction. And yet, humans were watching the golden frogs die out in real time.

Even when humans encountered a human-like species, the Neanderthals, 40,000 years ago, we likely wiped them out, too, but not before we had sex with them. Because, of course. Kolbert says many of us have 4 percent Neanderthal DNA.

When you put our DNA side-by-side with that of the Neanderthal and our other brothers and cousins, the apes, the DNA strains are strikingly similar, which makes it all the more remarkable and fascinating that some slight deviations caused all of, well, look around you — caused me to even read a book about it and write a review thereafter! Perhaps the strongest divider between us and any of our other closest “relatives,” Kolbert (correctly, I think) argues, is that we are a collaborative species. It is that same collaborative spirit that inspired all the conservation organizations the world over looking to save animals and plants.

When I was a teenager, I used to be of the mistaken mindset that humans were not “powerful” enough to so affect the climate, the Earth, and its many non-human inhabitants and plant life. But of course we are. That’s how we got to this point, for both better and for worse! I think the question, though, isn’t whether the Earth will survive us, or if life itself, whatever that looks like, will, because of course it will since both the Earth and life survived five other mass extinctions. Rather, the question is whether life as it currently exists, including us, will survive us.

That remains to be seen. I have confidence in human ingenuity to figure it out, but Kolbert rightly takes some shots at such lofty thinking toward the end. That’s fair! At the scale of a mass extinction and arguing we’re in the midst of it and the perpetrators of it (which I’m not disagreeing with), it’s hard to also imagine that we could put the brakes on it. It’s like the cops investigating themselves and finding no wrongdoing. I get the cynicism and weariness at such vague assurances. But also, just as human ingenuity got us to this point (of destruction), so, too, did it get us to this point (of creation), and perhaps salvation in the end.

Yes, I somehow am going to walk away from a book about the poor, cute golden frogs and the little hairy brown bats dying out, the Great Barrier Reef facing a tipping point, the oceans acidifying, great mammals facing extinction, and a book called, The Sixth Extinction, feeling optimistic, but I do! After all, I find it remarkable that I’m sitting around reading about it and meanwhile, there are brilliant humans out there reporting this information to me, like Kolbert, and brilliant humans saving these animals and plant life, and more brilliant humans either still trying to unlock the mysteries of the past, or figure out a way to stop this mass extinction-level event we’re causing. Humans are a fascinating species in that way. Admittedly, I might be biased, though.

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