For nearly 15 years, a panel of scientists has been chewing through a big question: Has our species transformed the planet so much that we have ushered it into a new period of geological time?
On Tuesday, the committee announced a key part of its case for our declaration. The group said it chose a secluded lake in Ontario to mark the beginning of the Anthropocene, a potential new chapter in Earth’s 4.6 billion-year history that could soon sit alongside the Cambrian, Jurassic and Cretaceous periods in defining the planet’s perilous periods. changes.
Scientists chose Lake Crawford over 11 other candidate sites because it contains the clearest and clearest evidence of human influence on the global geological record, group representatives said at a news conference in Lille, France. This evidence includes sharp changes in plutonium and radioactive carbon from nuclear explosions, and in fly ash from the accelerated combustion of fossil fuels.
McCarthy, a microbiologist at Brock University in St. Catharines, Ontario, and a member of the Anthropocene Working Group, the body that has been debating since 2009 whether and how to give the human lifespan a place in the official geological timeline.
Legalizing the Anthropocene would confirm that humans have changed the Earth so dramatically in recent decades that our current geological era, the Holocene, which began 11,700 years ago and fostered the conditions for the emergence of complex human civilizations, has come to its final end.
Scientists’ final verdict on the Anthropocene will determine the nomenclature used in academic studies, textbooks, and museums for future generations, and help shape humanity’s understanding of its place on Earth.
Preparing for such a huge announcement was not easy at all. And there are still ways to go before it becomes official.
Once the working group has written its formal proposal to recognize the Anthropocene epoch based on location in Canada, three other geological committees will vote on it, a process that could begin this fall. Sixty percent of each committee will have to approve the proposal in order for it to advance to the next committee. The certification of any country is far from guaranteed.
In fact, two of the 36-member Anthropocene Working Group recently resigned because they disagreed with the committee’s approach. Geologists on other voting committees may prove similarly reluctant to perpetuate a period that is still just a baby by Earth-time standards, no matter how much it affects the planet.
Jean A. “It’s going to be a really bumpy ride,” Zalasiewicz, a geologist at the University of Leicester in England and a member of the working group. “I’m not optimistic about the opportunities. But it’s an important part of the science.”
In 2019, the panel agreed, after a decade of debate, to recommend that the new era begin in the middle of the 20th century, a time when globalization, industrialization, and energy consumption began to accelerate. Late last year, members of the group began voting on a physical site known as the “golden spike,” where the rock record clearly separates the Anthropocene from the Holocene before it.
Almost all geological time units contain gold spikes, and they are not just symbolic symbols. Each one should have very distinct geochemical markers so that when scientists encounter unfamiliar rocks elsewhere, they can match the markers to roughly determine their age.
It took three rounds of voting, from last fall through spring, for the Anthropocene committee to select Lake Crawford, whose waters are so deep that whatever falls to the bottom is kept in the mud, piling up over time in a tree-like ring. Planetary change record. The other finalists were Sihailongwan, a crater lake in China, and Beppu Bay, off Kyushu in Japan.
“It was a very close call,” said Colin Waters, chair of the working group. “There’s been a lot of careful thought about this.”
In the coming months, the panel will also select ancillary sites that can help geologists define boundaries between the Holocene and the Anthropocene in other environments, not just lake beds. Like coral reefs, for example. or peatlands.
But for Philip L. Gibbard, a geologist at the University of Cambridge, it is as if the group is doing all this meticulous work to craft a definition of the Anthropocene that will be irrelevant when so many people arrive.
Dr. Gibbard joined the committee at its inception in 2009. But over the past several years, he has felt his views veer far from those of the rest of the group, he said. He and another member–Matt Edgeworth, an archaeologist–finally quit this year “in a rage,” he said.
As a term, the term “anthropocene” has long circulated outside the realm of the natural sciences, and the archaeologists, anthropologists and artists who use it are unlikely to listen to geologists who insist that it only applies to the world after World War II, said Dr. Gibbard. He said, “We are not policemen.” “We can’t tell colleagues in the social sciences what to do.”
The strict rules of the geological timeline also require that the New Age have a fixed starting point, which Dr. Gibbard believes would damage the sprawling story of mankind’s transformation of the planet.
Dr. Waters, chair of the working group, said he had known Dr. Gibbard for two decades, and they had always been on good terms. Dr. Waters said that now, after their split over the Anthropocene, and with the tone of their emails turning increasingly mournful, he wonders if Dr. Gibbard will speak to him next time they are at the same science conference.
“There’s a strange feeling about it,” said Dr. Waters.
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