April 15, 2024


The scientist Paul Crutzen got tired of the Holocene 24 years ago. The geological epoch reigned for 11,700 years, since the vast ice sheets covering North America and Europe began to melt rapidly, and Crutzen thought his time was over. The atmospheric chemist won a Nobel Prize in 1995 for demonstrating how humanity was destroying the ozone layer, just one of the many ways humans have radically changed the planet, from urbanization to emissions greenhouse gases. After repeatedly mentioning the Holocene at a scientific conference in Mexico, Crutzen lost his temper.

He interrupted a speaker and announced that the world had already entered a new era: the Anthropocene. The idea, which a few people considered as early as the dawn of the Industrial Revolution, implied that human activity was a powerful geological force, one that rivaled volcanoes and asteroids. “My comment had a huge impact on the audience,” Crutzen, who died in 2021, remember years later. “At first there was a silence, then people started discussing it.”

All these years later, they still discuss it. Since Crutzen’s outburst, the term Anthropocene has proliferated throughout the sciences, humanities, and pop culture. (The musician Grimes named one of her albums Miss Anthropocene.) The task of formalizing the geological age fell to the International Commission on Stratigraphy, the scientific organization that establishes global standards for such things. The earth system scientists who became part of the commission’s Anthropocene Working Group, created in 2009, found themselves at the center of a contentious debate as the world looked to them for a definitive answer: Are we living in the Anthropocene?

As differences came to a head, heated discussions, votes and resignations ensued. The latest drama came last week, when The New York Times reported that a committee of scholars rejected the working group’s proposal to declare the Anthropocene an official epoch after 15 years of debate. Some panelists disputed the report of the leaked vote. A press release shared by the committee chairman says the alleged vote violated the group’s rules and that an investigation into its annulment is being launched.

Periods are typically stretches of several million years designated by clues left in the soil, rocks and fossils. Even if some headlines suggested that the decision means Earth has not entered the “age of humans,” geologists and other experts say the vote should not change how people talk about humanity’s influence on the planet. Since the Industrial Revolution, climate change has warmed the globe by 2 degrees Fahrenheit (1.2 degrees Celsius) and more. The Anthropocene can still be considered a geological “event”, a more flexible term that would put it on par with major transformations such as the Great Oxidation Event, when oxygen became a major component of the Earth’s atmosphere more than 2 billion years ago became atmosphere.

“No one is saying that global change caused by humans is not significant,” said Erle C. Ellis, an environmental scientist at the University of Maryland, Baltimore County, and a former member of the working group. “It’s just about whether we should limit the Anthropocene definition to an epoch starting in 1952.”

The difficulty in pinning down a date stems from the fact that humans have been changing the planet for a long time. The relatively calm, warm conditions of the Holocene encouraged the development of agriculture. People planted crops and built cities and expanded civilization until they began to rebuild the earth itself. Somewhere in the midst of all this activity—the clearing of the world’s forests, the rampant burning of fossil fuels, and the testing of nuclear bombs—scientists say the planet entered the Anthropocene.

Last year, the working group settled on 1952 after identifying Crawford Lake in Ontario, Canada as the best place to find evidence of this new era. Nearly 80 feet below the glassy surface, the layer of mud at the bottom almost perfectly preserved hints of human history, such as corn pollen from nearby indigenous settlements from the 13th century and charcoal from a local logging site in the 19th. A layer of radioactive plutonium from mid-century nuclear weapons testing has been selected as a potential “golden peak,” a term for unique geological signatures that typically mark the beginning of new epochs.

Photo of a dried mud sample with many layers
A scientist examines a Crawford Lake core sample at the Royal Ontario Museum in Toronto. The specimen is considered a potential marker for the beginning of the Anthropocene epoch. Lance McMillan/Toronto Star via Getty Images

The group found “overwhelming evidence that there was a fundamental change in how the planet worked around that time,” said Francine McCarthy, an earth scientist at Brock University in Ontario, who led a team of 60 researchers that collected soil samples at Crawford Lake collected and examined. . For McCarthy, the controversial vote is a frustrating end to many years of work. “I don’t care what other people feel the beginning of the Anthropocene should be,” she said. “We spent 15 years, millions of euros to answer the question.”

The awareness that people can change their home irrevocably dates back to the dawn of the Industrial Revolution, when steam engines began to rumble and industrial factories emerged. George Perkins Marshan early American conservationist, declared in his influential 1864 book that humans are reshaping the earth—for the worse Man and Nature. In 1873, Antonio StoppaniAn Italian priest and geologist, proclaimed that the “Anthropozoic era” had begun, with no end in sight.

Scholars began to seriously consider the concept after World War II, when radiocarbon from nuclear bomb explosions established in the rock record. In 1955, 70 researchers from around the world met in Princeton, New Jersey for a symposium on “Man’s role in changing the face of the earth” for the first large-scale discussion of how humans have transformed the environment. But it wasn’t until 2000 that the idea really took off. Crutzen, along with the diatom researcher Eugene F. Stoermer, wrote a newsletter proposing the term “Anthropocene” for the current geological epoch.

Since then the word’s use gradually increasedand Google searches for interest followed a similar pattern. By 2014 it had landed in the country Oxford English Dictionary. In a surprising twist, the obscure-sounding term has escaped academic journals and entered the domain of popular culture, inspiring artists, novelistsand musicians. The scientists in the Anthropocene Working Group even became stars in a documentary.

For Dipesh Chakrabarty, a historian at the University of Chicago, hearing the term for the first time was career-changing. He moved from his work on South Asian history to writing on climate change, eventually publishing a handful of books on the subject. “I was very struck that geologists describe humanity as a geological force,” he said. “It’s something much bigger than I imagined people to be.”

However, not all scholars like the term. Some argue that it generalize the blame for climate change and other environmental problems, seemingly blaming everyone instead of the countries and industries most responsible. The discussion gave rise to a host of bizarre sounds accessories: the Capitalocene (blame capitalism), the Plantation ocean (blaming agriculture), and the Occidental Ocean (blaming rich, industrialized countries).

Ellis used to think that formalizing the Anthropocene as an epoch was a good idea, but last summer, after 14 years of heated discussion – and a dispute over narrowing the start date to 1950 — he resigned from the Anthropocene Working Group. Now he thinks that limiting the term to a technical definition can only confuse the public. The drive to establish the Anthropocene as an epoch was “an experiment in how to communicate the science of humans changing the planet,” Ellis said. “And it’s a failed experiment.”

“We can still use the term as we always have,” he said in the wake of the commission’s vote. “We just don’t need an epoch to attach to it.”






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