by The Triassic was the dawn of the dinosaurs. The Paleogene saw the rise of mammals. The Pleistocene included the last ice ages.
Is it time for humanity’s transformation of the planet to mark its own chapter in Earth history, the “Anthropocene,” or the human age?
Not yet, scientists have decided, after a debate that lasted almost 15 years. Or the blink of an eye, depending on how you look at it.
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A committee of about two dozen scholars, by a large majority, has voted on a proposal to declare the beginning of the Anthropocene, a newly created era of geological time, according to an internal notice of the voting results seen by the New York Times.
According to geologists’ current timeline of Earth’s 4.6-billion-year history, our current existence is in the Holocene, which began 11,700 years ago with the most recent retreat of the great glaciers. If the chronology were to be amended to say that we moved forward into the Anthropocene, it would be an admission that the recent human-induced changes in geological conditions were profound enough to bring about the Holocaust.
The declaration would shape terminology in textbooks, research articles and museums around the world. It would guide scientists in their understanding of our still-evolving existence for generations, perhaps even thousands of years, to come.
In the end, however, the members of the committee who voted on the Anthropocene in the past month were not only weighing how consequential this period was for the planet. They also had to wonder when, exactly, it started.
According to the definition that an earlier panel of experts spent nearly a decade and a half debating and crafting, the Anthropocene began in the mid-20th century, when nuclear bomb tests spread radioactive detectors around the world. For some members of the scientific committee that considered the panel’s proposal in recent weeks, this definition was too limited, too recent, to be a suitable sign of the reshaping of Homo sapiens on Earth.
“It limits, it limits, it dilutes the whole significance of the Anthropocene,” said Jan A. Piotrowski, a committee member and geologist at Aarhus University in Denmark. “What was going on during the beginning of agriculture? What about the Industrial Revolution? What about the colonization of America, Australia?”
“The human impact goes much deeper into geological time,” said another committee member, Mike Walker, an earth scientist and emeritus professor at the University of Wales, Holy Trinity. “If we ignore that, we’re ignoring the very, very real impact that people have on our planet.”
Hours after the voting results were circulated within the committee early Tuesday, some members said they were surprised by the margin of votes against the Anthropocene proposal compared to those in favor: 12-4, with two abstaining from voting. (Three other members of the committee did not vote or formally abstained.)
However, it was not clear on Tuesday morning whether the results stood as a final rejection or whether they could still be challenged or appealed. In an email to the Times, the committee’s chairman, Jan A. Zalasiewicz, said there were “some procedural issues to consider” but declined to discuss them further. Zalasiewicz, a geologist at the University of Leicester, has expressed support for the canonization of the Anthropocene.
This question of how to situate our time in the narrative arc of Earth’s history has brought the rare life of geological timekeepers to unfamiliar prominence.
The major-named chapters of our planet’s history are governed by a body of scientists, the International Union of Geological Sciences. The organization uses strict criteria to determine when each chapter began and what characteristics define it. The aim is to uphold common global standards for telling the history of the planet.
Geologists do not deny that our era stands out in that long history. Radionuclides from nuclear tests. Plastics and industrial ash. Concrete and metal pollutants. Rapid heating of a greenhouse. Sharp increase in extinct species. These and other products of modern civilization are leaving indelible traces in the mineral record, especially since the mid-20th century.
However, to qualify for its own entry on the geological time scale, the Anthropocene would have to be defined in a very specific way, one that would serve the needs of geologists and not necessarily the needs of anthropologists, artists and others who are already using them. the term.
That’s why many experts who doubted the cover-up of the Anthropocene emphasized that the vote against it should not be read as a referendum among scientists on the broad state of the Earth. “This has been a narrow technical topic for geologists, for the most part,” said one of those skeptics, Erle C. Ellis, an environmental scientist at the University of Maryland, Baltimore County. “This has nothing to do with the evidence that humans are changing the planet,” Ellis said. “The evidence keeps growing.”
Francine MG McCarthy, a micropaleontologist at Brock University in St. Catharines, Ontario, is the opposite: she helped lead some of the research to support the confirmation of the new age.
“We are in the Anthropocene, regardless of the time scale,” McCarthy said. “And our behavior accordingly is our only way forward.”
The Anthropocene project began in 2009, when a working group convened to investigate whether recent planetary changes deserved a place on the geological timeline. After years of discussion, the group, which included McCarthy, Ellis and three dozen others, decided to do so. The group also decided that the best starting date for the new period was around 1950.
The group then had to choose a physical location that would show a decisive break between the Holocaust and the Anthropocene. They settled on Lake Crawford, in Ontario, where the deep waters have preserved detailed records of geochemical change within the sediments at the bottom.
Last fall, the working group presented its Anthropocene proposal to the first of three governing committees under the International Union of Geological Sciences. Sixty percent of each committee must approve the proposal to pass it on to the next committee.
Members of the first, the Subcommission on Quaternary Stratigraphy, submitted their votes beginning in early February. (Stratography is the branch of geology that deals with rock layers and how they relate to time. The Quaternary is the continuous geological period that began 2.6 million years ago.)
Under the rules of stratigraphy, each interval of Earth’s time requires a clear, objective starting point, a starting point that applies worldwide. The group proposed the Anthropocene of the mid-20th century because it bracketed the post-war explosion of economic growth, globalization, urbanization and energy use. But some members of the sub-commission said that the history of mankind on Earth was a much more exciting story, a story that would not even have a single start date across every corner of the planet.
This is why Walker, Piotrowski and others prefer to describe the Anthropocene as an “event,” not an “era.” In the language of geology, events are a looser term. They do not appear on the official timeline, and committees do not need to approve their start dates.
However, many of Earth’s most significant events, including a mass extinction, a rapid expansion of biodiversity and the filling of Earth’s skies with oxygen 2.1 billion to 2.4 billion years ago, are called events.
Even if the subcommission’s vote is upheld and the proposal concedes to the Anthropocene, the new period could still be added to the timeline at some later point. He would, however, have to go through the whole debate and voting process again.
Time will go on. Evidence of the effects of our civilization on Earth will continue to accumulate in the rocks. The task of interpreting what it all means, and how it fits into the broad sweep of history, could be our world’s future legacy.
“Our impact is here to stay and be recognizable in the future in the geologic record — there’s no question about it,” Piotrowski said. “It will be up to the people coming after us to decide how to classify it.”
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