The Ends of the World: Volcanic Apocalypses, Lethal Oceans, and Our Quest to Understand Earth's Past Mass Extinctions
US: Jun 2017
“A perfect historian must possess an imagination sufficiently powerful to make his narrative affecting and picturesque,” Lord Macaulay wrote in an influential essay in the Edinburgh Review in 1828. Macaulay was intervening in a debate on methods for the writing of history, praising Thucydides for his practice of conjoining evidence with artful literary adornment and criticizing Herodotus for his practice of interweaving fact and fiction.
The distinction may seem obvious. But if the historical imagination so described by Macaulay is to be deployed rightly by the historian and thus provoked in the mind of the reader, at least two conditions need meeting. The writer must, first, exhibit control over the evidence, and second, possess some skill in shaping the evidence into a narrative that is understood and in some sense felt by the reader.
Brannen meets both conditions in The Ends of the World. The book foregrounds a history of the earth’s five mass extinctions in broad research in geology and paleontology, and although the bibliography includes articles in journals with titles like Evolutionary Ecology and Biogeosciences, it is not a formal academic work. Brannen’s background as a science writer and journalist is key to its persuasiveness because his viewpoint is that of the intellectually curious general reader, permanently dazzled by the parade of almost mind-warping facts and theories carefully built up by scientists to characterize the planet’s most recent 500 million year history.
Brannen’s approach as a journalist matters because geology has a public relations problem. Despite the deep presence of geology in the history and practice of the physical sciences and its conspicuousness in our everyday lives—its subject matter, after all, is under our feet, visible and tangible—historically it has lacked emissaries into the popular imagination. Certainly, the subject has its share of practitioners and proponents producing well-regarded work for targets outside academia—John McPhee, Simon Winchester, and Peter Ward come to mind—but take astronomy as a case study in contrasts. A quick Youtube search on astrophysics will turn up reams of content on the mass of a photon, the moons of Saturn, or the rotation of pulsars. There will be comparatively fewer videos explaining, for example, the principles and implications of stratigraphy and petrology. It must be said that Carl Sagan, Neil Degrasse-Tyson, and Janna Levin, to name only a few, are part of a special tradition of communicators with an eye for guiding metaphors and a capacity for conveying the wonders of astronomy.
In other words, the affecting and the picturesque are among the tools at their disposal as public intellectuals. So too are they available to Brannen and in The Ends of the World he variously assumes the roles of academic, journalist, and nature writer. The early pages are replete with amusing moments where Brannen seems to stop and think and wonder out loud about the ground beneath his feet and how it has changed over the last four billion years. “Rising out of the deserts of West Texas are the Guadalupe Mountains,” he writes, “a haunted monument built almost entirely from ancient sea animals in the full bloom of life before the single worst chapter in the planet’s history.” He describes columns of basalt and cliffs, “monuments to an ancient apocalypse”, made of magma that at one time “smothered the planet from Nova Scotia to Brazil.”
The wreckage of the five extinctions chronicled in the book are still with us and Brannen appreciates that it strains the imagination to really grasp the magnitude of tectonic changes, climate shifts, and the extent of biodiversity that characterizes the whole of the earth’s history. So he assumes the role of journalist and popular science writer and fills the book with conversational adjectives, images, and anecdotes that seem designed to help the reader negotiate the challenge of grasping the staggering depths of geological deep time. (Although a simple flow-chart would have helped too. I returned again and again to a dashed off remark in an early footnote to help keep timelines straight in my head.)
The fern-like “pseudo-creatures” of the Ediacaran period 540 million years ago, for example, a weird attempt at life still entombed in the fossil record in southeast Newfoundland, are described in a good turn of phrase as resembling “graffiti left by alien”. We are invited to pause to consider facts that might be well known but maybe not well appreciated in geological context, e.g., that while the earth may be teeming with life now, for its first 4,000 million years it was effectively barren. Or that the humble trilobyte wandered the planet for 300 million years, putting the modest 200,000 year run of homo sapiens in proper deep-time perspective. Or that the End-Cretaceous mass extinction 66 million years ago was marked, first, by the largest asteroid impact known to have hit the planet in 500 million years, and second, by one of the largest volcanic eruptions in the planet’s history covering present-day India in lava more than two miles deep. Disorienting, vast beyond comprehension, “marooned in time, between incomprehensible eternities” are among words and phrases Brannen deploys to characterize and illuminate this strangeness at the heart of geology.
But The Ends of the World is also about cultivating some basic science literacy on the subject. The main scientific thread Brannen carries throughout the book is around the carbon cycle, human destructiveness, and how to square such phenomena and behavior with the structures of long-term climate change. It is true that we are currently living in the midst of a window of relative warmth and stability called an interglacial period, a brief respite caused by a tilt in the Earth’s orbit in and out of sunlight at 10,000 year intervals. But the crux of the book’s science content consists of the small, large, and cumulative ways human beings have transformed the chemistry of oceans and atmosphere and the probable short and long-term consequences of our overwhelmingly poor stewardship of the environment.
It turns out that all five of the planet’s mass extinction events (at approximately 445, 374, 252, 201, and 66 million years ago) have, in various ways, been associated with disruptions to the earth’s carbon cycle. This, as one of Brannen’s geologists remarks, is the driver of extinction. Normally the carbon cycle—the process whereby excess carbon dioxide in the atmosphere is converted to rock and buried in the ocean—acts as a kind of thermostat for regulating the Earth’s climate. But the process takes place over the course of hundreds of thousands of years and the thermostat is vulnerable to breaking if the pace at which carbon dioxide is released into the atmosphere suddenly increases. In terms of absolute volume, the amount of fossil fuels burned by human beings since the 18th century cannot compare to, for example, the 48,000 gigatons of carbon dioxide produced by the volcanic eruptions of the Siberian traps at end of Permian era. But at 40 gigatons per year, human beings are emitting carbon dioxide at the fastest pace of any point within the last 300 million years.
All things being equal, as carbon dioxide goes, so goes the climate. This has been an uncontroversial tenet of geoscience for more than a century and some consequences of short-circuiting the carbon cycle in such a manner are more well known in the popular imagination than others. One key goal of the 2015 Paris Accord was to implement a plan to prevent the planet from warming by two degrees by 2100. For perspective, if humanity was to burn through its entire reserves of fossil fuels it would warm the planet by as much as 18 degrees and elevate sea levels by hundreds of feet. Even one quarter of these worst-case figures would, in Brannen’s words, “create a planet that would have nothing to do with the one on which humans evolved, or on which civilization has been built.”
Another relatively lesser known consequence is the acidification of the oceans and Brannen is strong on this point. Alongside rising temperatures and sea levels, a sharp increase in carbon dioxide has the effect of reacting with seawater in such a way that lowers the pH balance in the ocean, making it more acidic and reducing the amount of carbonate that corals, plankton, creatures with shells, and other forms of marine life need to survive and flourish. To quote Brannen: “The terrifying reality of ocean acidification has only fully dawned on the scientific community in the last decade or so. Even more so than global warming, ocean acidification is what people who understand the fossil record, and who think about the future of the oceans, are most distressed by.” At this point we seem to have licence to use such an unambiguous term as “kill mechanism”.
Human beings have never lived in harmony with nature—not before the Industrial Revolution, not before European colonialization, not in the tens of thousands of years before that, not ever. The history of human expansion into Australia, Asia, Europe, and North America between 50,000 and 12,000 years ago is a record of a single species equipped with consciousness, culture, and intelligence to dominate its environment and produce wave after of wave of extinction. The record of destruction that has followed human beings since their emergence is, in his words, “one of the stark and unsettling discoveries of science.”
Brannen and his authorities believe that our predations have not yet brought us to the brink of a sixth mass extinction. But by connecting deep time with human time, the picturesque with the disastrous, and the micro with the macro, The Ends of the World shows that there may yet be inescapable consequences for our history and habit of improvident behavior.
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