The Sixth Extinction by Elizabeth Kolbert [A Review]

In The Sixth Extinction, Elizabeth Kolbert examines the environmental catastrophes the world is currently experiencing in the context of a mass extinction event. A well-written, fascinating and horrifying account, The Sixth Extinction won the Pulitzer Prize for General Non-Fiction in 2015. However, if you were hoping for book infused with scientific rigor, to be guided by a mentor of capable expertise, you may be disappointed.

In 1982, palaeontologists Jack Sepkoski and David Raup identified five mass extinction events in the Earth’s history. Five instances where the world experienced a widespread and rapid decline of biodiversity. We have all heard of the most recent one – the K-Pg Extinction which ended the era of the dinosaurs 65 million years ago, most likely caused by an asteroid impact in what is now Mexico’s Yucatán Peninsula.

Five instances over the space of some 450 or so million years makes them one of the rarest events on our planet, however, we may be currently experiencing a sixth. Though quantifying it is difficult for a variety of reasons – for example, many species are going extinct before science can properly identify them – we are currently experiencing another decline large enough to qualify as a mass extinction event. It has even been proposed (but not yet accepted) that the changes the planet is currently experiencing recommend the creation of a new geological epoch, presumptively dubbed the ‘Anthropocene’. The causes of past mass extinctions are also difficult to determine. As well as asteroid impacts, massive volcanic activity and changes to atmospheric chemical composition from various causes, have all been suspected. In the case of the current mass extinction, which has been named the ‘Holocene Extinction’, the cause is human activity.

Elizabeth Kolbert, a journalist for The New Yorker, describes the potential for a sixth mass extinction event as something exciting and fascinating – to witness an incredibly rare event – and horrifying in terms of what it might mean. In The Sixth Extinction, she travels the world to see the evidence for the past extinction events, to witness the current extinction in action and to talk to experts in the field. She also covers the history of scientific thought on extinction and how it has evolved, from Georges Cuvier to Charles Lyell and Darwin. Devoting each chapter as she does so to a particular species, emblematic of the story she is telling.

What she finds is that biological diversity is declining at an alarming rate. The cause is human activity from overhunting and overfishing, pollution and global warming, follow-on effects such as ocean acidification and that species decline is even occurring accidentally or inadvertently as a consequence of global travel and trade.

Followers of this blog will know that one of my pet peeves is books on technical subjects – history and science usually – written by non-technical writers – journalists usually (see my reviews of The Genius Factory by David Plotz, In Search of Zarathustra by Paul Kriwaczek and The Last Jews of Kerala by Edna Fernandes). These sorts of books suffer numerous general faults and The Sixth Extinction is no exception. In addition, The Sixth Extinction has some faults specific to itself.

You might wonder why I keep picking up books like this if I know they are going to frustrate me. That’s because of the things they do well. For one thing, these sorts of books tend to be topical or focus on some overlooked niche, no doubt a result of journalists discovering these topics in the course of their work. More academic writers tend to write books with wider scope or on well-known events and subjects.

Also, books like this tend to be well-written. There are plenty of books written by experts that are dry, difficult, long, overburdened with detail and will utterly deflate most readers enthusiasm and curiosity for the subject. I happily persist with them, especially if I feel I am continually learning and because I can feel confident in the author’s expertise on the subject, if not their ability as engaging writers. But I can understand why many readers are not so persistent. It makes those writers who know their stuff, can inspire enthusiastic reading and educate the reader on difficult subjects, rare and special. Simon Singh and Richard Dawkins are two of the best in my experience. Kolbert is a good writer. Though not a long book, reading The Sixth Extinction will take you even less time than you may think; it is a light, easy and otherwise enjoyable read on a fascinating and relevant subject.

The first general fault of these sorts of books is that, while not bogged down with detail, they are padded with the superfluous. Writers like Kolbert want to provide physical descriptions of each location they visit and every person they meet. Occasionally this might be relevant but almost always it is not. Some readers may find this engaging, but I feel like I am reading a travel book trying to reach a minimum word count.

When I visited Reserve 1202, I ran into a graduate student from Portugal who was surveying bats. At noon he had just recently woken up and was eating pasta in a shed that served as a research station-cum-kitchen. While we were talking, a very skinny cowboy rode up on a slightly less skinny horse. He had a rifle slung over one shoulder. I wasn’t sure whether he’d come because he’d heard the truck I’d arrived on and wanted to protect the student from possible intruders, or because he sensed there was pasta.

As well as the superfluous, there is the subjective. Writers of books like this seem determined to insert themselves into the book and elevate the importance of their own experience to the level of the topic. They have to describe their experiences researching the book especially how certain moments made them feel. There is an episode in The Sixth Extinction where Kolbert is determined to visit the island of Eldey, the place of the last sighting of a living Pinguinus impennis – the great auk; a penguin-like aquatic bird related to puffins. It was a little difficult to find someone willing to take her, since the uninhabited island it is a little out of the way. But, since nothing really informative was to be gained, the trip to see Eldey was ultimately pointless; for her, for inclusion in the book and for the reader to read about. Especially since she did not have a permit to set foot on Eldey and could only see it from a distance.

Then there are the specific issues which in the case of The Sixth Extinction is the author’s apparent lack of understanding of science and the scientific method and of the topics examined. At an early point in the book Kolbert says:

In times of extreme stress, the whole concept of fitness, at least in a Darwinian sense, loses its meaning: how could a creature be adapted, either well or ill, for conditions it has never before encountered in its evolutionary history?

It is the sort of statement that makes me wince. And it is difficult to know how to respond to it. Is it just an oversimplification? A misrepresentation? Is the problem that it is too certain and definitive? Is it just slightly wrong or very wrong? And should the reader just ignore it, let it slide, or take issue with it?

As Kolbert admits elsewhere, some individuals and some species will thrive in new conditions. ‘Fitness’ is still the relevant factor, even if what constitutes ‘fitness’ has changed. Whether the species has encountered similar conditions in its evolutionary history is probably not as relevant, however.

I should stress at this point that I am not an expert in these matters. The point, and the problem, is that neither is Kolbert (from what I can tell her background is in literature and art). And when she makes definitive statements like this, that you know are at best misrepresented, your faith in her book plummets. Even the idea of five major extinction events in the Earth’s past has been blurred since Sepkoski and Raup’s original 1982 paper with the discover of several ‘minor’ mass extinction events and periods. Mass extinction events are arguably not as rare as Kolbert supposes, and the ‘big five’ may not necessarily be the biggest anymore.

Climate change alone “is unlikely to generate a mass extinction as large as one of the Big Five,” [Chris Thomas, a biologist at the University of York] wrote. However, there’s a “high likelihood that climate change on its own could generate a level of extinction on par with, or exceeding, the slightly ‘lesser’ extinction events” of the past.

One of the early topics of this book, and an enjoyable one to learn about, is the history of ‘extinction’ as a concept and a scientific fact. Though Kolbert avoids explicitly saying so, there is an unavoidable sense in the early book that she places much of the blame for how long it took for science to accept mass extinction events as a fact at the feet of Darwin and to a lesser extent Charles Lyell. Both were ‘uniformitarians’ – they held that the history of the Earth was one of small accumulating change; they were not ‘catastrophists’ who argued for periods of rapid upheaval that resulted in, among other things, mass extinction events.

Kolbert seems convinced that someone as insightful, knowledgeable and careful as Darwin should have known better; that the evidence for mass extinction was present in the fossil record of his time and that he was probably aware (though we can’t be certain) of the extinction by overhunting of the great auk. Darwin instead held that extinction was probably a rarer event than speciation and he and others believed it was the incompleteness of the fossil record that created a false impression of mass extinctions. Kolbert portrays science as an institution that errs too heavily on the side of caution and maintains a status quo, despite evidence to the contrary, until it becomes utterly untenable, referencing Kuhn’s work on scientific revolutions as she does so.

I am not so sure. Individual scientists, being human, may not always be rational, but in general, I think science as an institution does, and must, follow where the best evidence leads. There are many seemingly compelling alternatives to accepted theory, some of which may one day overtake the accepted theories, but only once the evidence justifies the changeover. The more extraordinary the claim, the more extraordinary the evidence required to support it. From the outside, and in hindsight, this may seem overly conservative, but the alternative is untenable and would make knowledge an utterly unreliable matter of opinion. I also don’t think caution was at play in the specific case. Darwin and Lyell were not so revered they escaped detraction and they had no shortage of challengers for every detail of their theories. It seems unlikely that the failure of the catastrophist position persisted due to favouritism, more likely it was the lack of significant evidence.

The suggestion that scientists in the 19th century should have known better rests on evidence that was not available, gathered from techniques not yet developed or that they should have taken the minority view contrary to the best explanations of the best evidence. Arguably – and even Kolbert’s account concedes – the overturning evidence did not arrive until the early 1980’s with the establishment of the impact theory for the K-Pg extinction event. Even then, this was not an overturning of the uniformitarian view. Instead it showed the dichotomy between uniformitarians and catastrophists to be a false one – the history of life is overwhelmingly one of slow gradual change, punctuated by events of mass extinction.

“Those eleven years [that it took for the impact theory to gain wide acceptance] seemed long at the time, but looking back they seem very brief,” Walter [Alvarez – co-postulator of the impact theory] told me. “Just think about it for a moment. Here you have a challenge to a uniformitarian viewpoint that basically every geologist and palaeontologist had been trained in, as had their professors and their professors’ professors, all the way back to Lyell. And what you saw was people looking at the evidence. And they gradually did come to change their minds.”

Kolbert’s grasp on the basics of the scientific method does not appear to be strong. There are a couple of telling encounters late in the book. When she questions Svante Pääbo, head of the Max Planck Institute for Evolutionary Anthropology’s department of evolutionary genetics on what he thinks Neanderthals were like, Pääbo seems to get defensive. He folds his arms and says he does not want to be drawn into speculation. Kolbert, as one more ‘inclined to speculate’, then proceeds to. When she examines prehistoric artefacts made by Neanderthals, or perhaps early Homo sapiens, she puts her own interpretation on them and is somewhat rebuked by an archaeologist for projecting the present onto an object from the past to suit a particular explanation without sufficient cause.

But it would be unfair and inaccurate to accuse Kolbert of Darwin-bashing. She repeatedly gives him credit for the assertions and predictions he made that were proved correct. Despite the early impression of blaming Darwin and Lyell for the supremacy of the uniformitarian position, she also provides the history and information that can be used to argue that it could not have been otherwise. When mentioning that Darwin believed extinction would be extremely rare, Kolbert admits that Darwin qualified his position on extinction by stating that it was the case under the normal conditions of natural selection. Darwin also mentions extinction caused by human activity in On the Origin of Species. Which begs further questions of how do things play out when conditions are not normal? To what extent is our species’ tendency to rapidly exploit and alter the environment part of our nature and therefore natural? But while Kolbert adds this information and explores these issues a little, it does not come across as adding complexity and nuance to educate the reader, more as a case of a self-contradiction of what came earlier.

It would also be unfair and inaccurate to say that Kolbert is necessarily anti-science on the basis of this book alone. Though, The New Yorker magazine where she has been a staff writer since 1999 is increasingly seen as an outlet that is hostile to science and empiricism and articles such as Kolbert’s review of Steven Pinker’s The Better Angels of Our Nature are seen as an example of this hostility. At least, when she received pushback from experts such as the above examples, she included them in the book when she might not have.

Instead, the factor that I think connects all these threads and explains the pattern in the book is that Kolbert is somewhat careless and cavalier with her words. On one page Kolbert says of Neanderthals that “clearly they were not humans” (her emphasis). Another wince-inducing definitive statement that completely ignores the complexity behind it and would require much unpacking. Later, she says Neanderthals are ‘so-called archaic humans’. Again, there is a pattern here where instead of beginning with a carefully considered position and explaining the reason for the care like an expert would, she begins with an over-simplified authoritative statement of her own preconception and later adds information which only seems to confuse and contradict her earlier position.

What I am calling ‘self-contradiction’ might more generously be said that Kolbert is sharing a journal of her own learning – starting from a place of ignorance and expanding her knowledge from there – or that she is trying to present competing theories. But then, when writing the book, why start with limiting, definitive statements that you already know are going to be later contradicted or at best refined and reworked? Where you want to be led over difficult terrain by a knowledgeable guide, with Kolbert you end up, not lost, but wishing for much better.

Kolbert also has the tell-tale tendency of the non-expert for exaggeration and hyperbole. At one point she says that should the Anthropocene be accepted as a new geological epoch, “every geology textbook in the world immediately will become obsolete”. Umm, no they would not. Every geological textbook would still likely be more than 99% accurate and useful.

And though I have given her some credit for eventually elaborating on why the uniformitarian position endured, it was not before she had thrown around words like ‘wrongheaded’ or said without specificity that Darwin’s theory had been ‘proved wrong’.

As I said, it is difficult for the reader to know what to do with all this. Do we apologise for Kolbert and let these things go because we think we know what she means if we don’t take her literally and the general gist of her book is fairly sound? Or do we take issue, and say it could have been done better without much difficulty and risk being seen as unfairly zealous? As you can see, I have taken the latter. There is the argument that this book is for the ‘general reader’, but plenty of historians, scientists, and other experts have written great books on difficult subjects, with more care and accuracy, suitable for the general reader.

When I was a few chapters into The Sixth Extinction, I felt that it may not be a book I would recommend to my more scientifically-literate friends but perhaps to those who do not normally read books on scientific subjects who may find it light and interesting. A sort of gateway book that might encourage them to pick up something more rigorously scientific. But by the end I felt I would not recommend it at all; it may only prove misleading.

I say that even though this book contained some very interesting parts. I learned about the Signor-Lipps Effect, Latitudinal Diversity Gradient, and the Species-Area Relationship, for example. But because of this book’s faults I don’t feel confident in Kolbert’s descriptions and explanations of these ideas. Again, I give her credit for not only including a bibliography but also notes of her sources. I will want to find more reliable information on the things that interested me rather than trust this book and I am a little shocked that this book won the Pulitzer Prize.

All this is very disappointing. The development of extinction as a concept, the identification of mass extinction events and theories as to their causes, is a fascinating story. The fact that we may be witnessing a mass extinction event is equally alarming. Again, I stress that the gist of this book is fairly sound and I don’t dispute it – we are experiencing a mass extinction event, which not only places a large proportion of the world’s species in jeopardy but ourselves as well, and denialism – though not so much from the scientific community – is a real obstacle, but the book frustrated me in the details. Unfortunately, I can’t help but feel that these fascinating, relevant and important subjects have been fumbled by a writer who did not have the expertise for the task.

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