The Sixth Extinction: An Unnatural History, by Elizabeth Kolbert (2014)

The winners of the Pulitzer Prize were announced this week, and Elizabeth Kolbert’s The Sixth Extinction won in the category of General Nonfiction. I’ve followed Kolbert since she published her three groundbreaking “Climate of Man” articles on climate change in the New Yorker in April and May of 2005, articles that became part of her 2006 book, Field Notes from a Catastrophe, and I’m excited to see her get this level of recognition. The stories of global warming and biodiversity loss covered in these two books are every bit the bummer their titles suggest, but Kolbert brings such intelligence to the topics and has such a gift for anchoring general trends in stories of particular places and people that they become page-turners. 

The Sixth Extinction begins with the tale of the emergence of Homo sapiens some two hundred thousand years ago and their curious habit of killing off many of the species they came in contact with, especially the large ones – like big cats, bears, and tortoises – with the double-curse of having meat on their bones but being slow to reproduce. Humans changed the composition of the planet in countless other ways too, pulling up the stored energy from millennia past to power their exponential growth and restless desire for speed. This new conception of space and time outpaced evolution in every way imaginable, so that the planet’s patterns of life and movement were radically altered and its flora and fauna began to die off at an even more alarming rate. “Very, very occasionally in the distant past,” Kolbert writes,

“the planet has undergone change so wrenching that the diversity of life has plummeted. Five of these ancient events were catastrophic enough that they’re put in their own category: the so-called Big Five. In what seems like a fantastic coincidence, but is probably no coincidence at all, the history of these events is recovered just as people come to realize that they are causing another one.” (3)

Kolbert tells the story of this recovery, beginning with Georges Cuvier, an 18th-century curator and researcher at Paris’s Museum of Natural History who proposed the then-unbelievable idea that the biotic makeup of the earth was once much different from the one we know now – that, in effect, some species had gone extinct. His evidence included mastodon molars the size of bricks, the skeletons of a giant sloth, a tiny hippopotamus, an uncommonly large elk, and more than a dozen other animals.

Stories like Cuvier’s form the heart of Kolbert’s book: researchers patiently doing their work piecing together a record of the planet’s history, testing hypotheses about what’s happening now, and making informed predictions about where we’re headed. Each chapter centers on a single species and one or more scientists devoted to observing it. The chapter on the great auk, a large, flightless penguin-like bird that ranged primarily in the North Atlantic and is presumed to have been finished off in Iceland in 1821, is a reminder that humans have often been the direct cause of species extinction through over-hunting.

Just as often, though, the causes are more complex, and the effects of such extinctions are always complex. Kolbert travels to the Brazilian rainforest, where some of the world’s most famously dramatic changes are taking place. One of the defining features of the rainforest are the “islands” of relatively untouched areas surrounded by cut-over seas of pasture used for cattle grazing and road-building. One of the many species threatened by this pattern has few human fans: the army ant. But, as Kolbert explains, these ants are the key player in their own migratory ecosystem, and their disappearance threatens all the species associated with it:

“There’s a whole class of birds known as obligate ant-followers. These are almost always found around ant swarms, eating insects the ants have flushed out of the leaf litter. Other birds are opportunistic ant-followers and peck around the ants when, by chance, they encounter them. … There are butterflies that feed on the birds’ droppings and parasitic flies that deposit their young on startled crickets and cockroaches. … A pair of American naturalists, Carl and Marian Rettenmeyer, who spent more than half a century studying [the army ants], came up with a list of more than three hundred species that live in association with the ants.” (184)  

Deforestation and the constant background noise of global climate change place these and thousands of other species in a double bind. Loss of habitat and/or changing climactic conditions force them to move, but development “create[s] barriers – roads, clear-cuts, cities – that prevent them from doing so” (189). Worldwide, the combination of forces unleashed by humans on our fellow earthlings has accelerated the rate of species extinction to 10,000 times the normal pace, so that as many as 14 species might die off, never to return, in a single day. If we want to know the costs of our success at wearing down the confines of time, space, and their attendant inconveniences, it is hard to think of a more sobering price tag than this one.

Kolbert’s book is valuable in part because it brings home a point wildlife activists have been hammering for decades: pollution and changing weather are abstract, even boring, rhetorically speaking, but animals have faces and preferences, and they feel pain. We take mammals and birds and fish into our homes and treat them as part of our families, and when they die we grieve, sometimes deeply (well, maybe not for the fish). Thinking of the effects of our actions in terms of animal suffering rather than hotter weather, more wildfires, or more violent storms, seems to hold more rhetorical power. And in a twisted way, this is the upside of the Sixth Extinction – the book and the mass event. The downside, according to Kolbert, is that obliterating the diversity of life in the spaces we inhabit – which by now is all the space on Earth – is simply what we do. Kolbert puts it this way toward the end of her book:

“It doesn’t much matter whether people care or don’t care. What matters is that people change the world. … Indeed, this capacity is probably indistinguishable from the qualities that made us human to begin with: our restlessness, our creativity, our ability to cooperate to solve problems and complete complicated tasks. As soon as humans started using signs and symbols to represent the natural world, they pushed beyond the limits of that world. ‘In many ways human language is like the genetic code,’ the British paleontologist Michael Benton has written. ‘Information is stored and transmitted, with modifications, down the generations. Communication holds societies together and allows humans to escape evolution.’ Were people simply heedless or selfish or violent, there wouldn’t be an Institute for Conservation Research, and there wouldn’t be a need for one. If you want to think about why humans are so dangerous to other species, you can picture a poacher in Africa carrying an AK-47 or a logger in the Amazon gripping an ax, or, better still, you can picture yourself, holding a book on your lap.” (266)