Book Reviews Science Communication

Deep Blue Reads: The Sixth Extinction, by Elizabeth Kolbert

As a novelist writing about oceanography, I spend a decent amount of time parsing scientific studies. Over the past several years my vocabulary has expanded to include terms like band saturation, turbidity currents, and foraminifera—phrases and words that had not existed in my wildest dreams when I first started writing. I’ve relied on studies and on the generosity of practicing scientists to gain the broader view of ocean sciences that I need in order to write convincingly about life aboard a research vessel in pursuit of more and more detailed information about the oceans we depend on and coexist with.

But I’ve found that sometimes I need a bigger picture than the one I can get from those who are fully steeped in the material and for whom scientific jargon is practically a native tongue. For that I turn to more “popular” books about science, those written—often by journalists rather than scientists—for a mainstream audience. Those books put the studies and data into a broader context, whether social or historical. And they do so in a way that is fully comprehensible to someone, like me, who is primarily trained in the humanities rather than the hard sciences.

These days, as our lives are increasingly impacted by forces—like climate change—that we need science to understand, too many non-scientists are woefully scientifically illiterate. That’s where this column comes in. Each month, I’ll be reviewing a different book that deals with ocean sciences for a general audience. For those of you who come to oceanbites because you aren’t scientists but want to know more, I aim to guide you to resources that can provide you with a solid foundation to understand the more technical information that appears here and elsewhere. For those of you who are scientists, I offer this column as an invitation: to take a minute to extend beyond your research to a broader scope; to read these books I review as models for how you might explain your research to a general public that needs to understand what you’re discovering and confirming but may not know how to get there; to offer these books to those in your life who may need something in addition to “Sedimentary response to Paleocene-Eocene Thermal Maximum carbon release: a model-data comparison” to understand how the oceans and climate have changed over the course of Earth’s history.

Make sense? Let’s get started.

Elizabeth Kolbert’s The Sixth Extinction: An Unnatural History takes on climate shifts throughout earth’s history, focusing primarily on the effect of these shifts on biodiversity. As Kolbert points out, through our use of fossil fuels, humans have changed the composition of the atmosphere, with the result that “extinction rates soar, and the texture of life changes.” Kolbert is interested in the fact that such a reordering of life has happened in the past—in extinctions known as the Big Five—but this is the first caused by one species: us. “While it is still too early to say whether it will reach the proportions of the Big Five,” she acknowledges, many have still termed it the Sixth Extinction.


The Sixth Extinction, then, is a biography of sorts, with humans and their impact on biodiversity as its subject. In each chapter Kolbert focuses on a species—the American mastodon, the ammonite—and uses its history to illuminate the history of human discovery and impact. She explains the great extinctions of the past and then turns to the one currently occurring to point out their commonalities, and the great divergence among them: that this time, we are the ones tanking the biodiversity of our planet.

For oceanographers, two chapters will be of particular interest: chapter 6, “The Sea Around Us,” and chapter 7, “Dropping Acid.” In chapter 6, Kolbert uses the case of Castello Aragonese, an island in the Tyrrhenian Sea circled by vents that spew carbon dioxide (CO2), to explain the effects and magnitude of ocean acidification. In chapter 7, she travels to the Great Barrier Reef to look in particular at how ocean acidification and sea temperature increases are impacting corals, and she explains the likelihood that reefs across the globe may soon disappear, taking with them entire ecosystems. In each case she describes with urgency—but without overwrought hysteria—how much this will change our lives as we know them. It is all, as she quotes one scientist as saying, “rather alarming.”

Each chapter in The Sixth Extinction builds to create a clear-eyed picture of where we’re heading, but Kolbert is a staff writer for The New Yorker, and indeed, each chapter could easily be read on its own if the reader is particularly interested in one subject over the others. (In fact, several chapters appeared in the magazine in slightly different form as a twopart series titled “The Lost World.”) Kolbert provides enough background information in each chapter to orient a reader who has skipped ahead—or a reader who is particularly forgetful—without slipping into frustrating repetition.

For the most part, Kolbert delves into plenty of scientific and technical detail, explaining, for example, the process by which CO2 affects calcifiers and the mechanism by which coral bleaching occurs. There are, however, times where she glosses over something a curious reader will regret not learning more about, like when she tantalizingly mentions that ocean acidification “will alter the way sound propagates” in the ocean, making the seas overall noisier, without explaining why that’s the case. Of course, a diligent reader can google to find the reason (one reason, in short: the borate-to-boric-acid reaction), but it would be nice to not be tugged away from the book into an internet wormhole.

Still, Kolbert is a master scientific journalist, and each topic she grapples with, no matter how esoteric it may seem to the lay reader, resolves itself into a clear image by the time she’s done. The balance of narrative—the details of her trip to One Tree Island off the coast of Australia, for example—with scientific information allows the reader to feel immersed in a story that builds intuitively, which in turn enables the information Kolbert embeds to feel logical, timely, and instinctive. The Sixth Extinction is a powerful investigation of the impact humans have had and are having on our environment, and it is one that scientists and nonscientists alike would do well to spend time reading.


Know of a book that would make a great Deep Blue Read? Email Elizabeth at elizabeth.weinberg[at]

One thought on “Deep Blue Reads: The Sixth Extinction, by Elizabeth Kolbert

  1. A great review! Even though I’m a trained as a scientist, I find that when I’m getting started in areas that aren’t may specialty, sources like this are a great place to start. Another great beginning place is kids books on a subject. Kids’ authors really know how to get right to the important points.

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