Letters: ‘The Anthropocene Epoch Is Not Hubris’

Members of the Anthropocene Working Group defend the proposed geological epoch.

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The Anthropocene Is a Joke

In August, Peter Brannen argued that the period during which humans have had a significant impact on Earth—which some scientists have proposed calling the Anthropocene—should not be considered a new geological epoch.

Peter Brannen asserts that little will ultimately remain of human changes to the Earth, arguing that they are a brief  “event” rather than the beginning of an Anthropocene epoch. We share his distaste for hubris and anthropocentrism, but Brannen has not reckoned with the reality that our activities have permanently altered life on Earth, and that we have left physical, chemical, and biological traces that will persist far into the geological future.

Geologists have long known that the duration of a geological event and its significance are distinct. The asteroid impact that drove extinctions at the end of the Mesozoic Era 66 million years ago was an instantaneous “event”—yet it wrought profound changes in Earth systems and permanently altered the course of life. This is why geologists use deposits from that impact to mark the beginning of the succeeding Cenozoic Era. Sudden global warming 56 million years ago was an “event”—yet the changes to the Earth-life system that cascaded from that geologically brief fever are used to mark the beginning of the 22-million-year-long Eocene epoch.

So it is with the Anthropocene. Humans have mixed faunas and floras globally, lopped branches from the tree of life, and greatly increased the abundance of selected species. Even if we avoid another mass extinction, we have already deflected future biological history. Human-caused changes to Earth systems are also no blip. Industrially generated CO2 already in the atmosphere (about a trillion tons, and rising) will likely eliminate the next glacial phase altogether, changing ocean chemistry and climate history for hundreds of thousands of years to come. Human shaping of landscapes is even more durable. The subterranean roots of cities—subway tunnels, pilings, millions of boreholes—are buried deep below the reach of erosion and set to last far longer than dinosaur bones. Even eroded material does not vanish mysteriously from the planet—it simply accumulates elsewhere to form distinctive, preservable strata rich in concrete, plastics fragments, metal alloys, composite materials, synthetic organic pollutants, and other geochemical fingerprints of industrial civilization. Radioisotopes from atmospheric detonations of nuclear weapons may decay with time, but do not disappear. They reconfigure to new isotopes that will show a permanent, discernible spike. The Anthropocene already has a far more striking set of durable sedimentary markers than many other geological epochs.

Brannen insists that “the idea of the Anthropocene inflates our own importance by promising eternal geological life to our creations.” But the Anthropocene promises nothing of this kind—it merely recognizes reality. Its essence comes not from Ozymandias but from Faulkner: “The past is never dead. It’s not even past.” The Anthropocene epoch is not hubris: It’s simply a recognition of the geologically long shadow cast by what we have already done. That recognition is the first step in learning to mold the planetary future thoughtfully rather than accidentally. That’s certainly no joke—a point upon which Brannen might agree.

Scott Wing, Jan Zalasiewicz, Colin Waters, John McNeill, Will Steffen, Erle Ellis, Naomi Oreskes, Michael Wagreich, Daniel DeB. Richter, Colin Summerhayes, Peter Haff, William Shotyk, An Zhisheng, Anthony Barnosky, Alejandro Cearreta, Matt Edgeworth, Phil Gibbard, Jacques Grinevald, Martin Head, Catherine Jeandel, Reinhold Leinfelder, Neil Rose, Mark Williams
Members of the Anthropocene Working Group

Editor’s Note: In response to this letter and other criticism, Peter Brannen talked to Scott Wing about the meaning of the Anthropocene and the ways in which humans might affect Earth’s future.