The Triassic marked the dawn of dinosaurs, the Paleogene saw the rise of mammals, and the Pleistocene encompassed the last ice ages. Could it be time to designate humanity’s impact on the planet with its own chapter in Earth’s history, the “Anthropocene” or the age of humans? Not quite yet, scientists have concluded, after a nearly 15-year debate—or, depending on perspective, in the blink of an eye.
According to an internal announcement of the voting results obtained by The New York Times, a committee of approximately two dozen scholars has rejected a proposal to declare the beginning of the Anthropocene, a newly proposed epoch of geologic time. Currently, based on the timeline established by geologists for Earth’s 4.6-billion-year history, we are situated in the Holocene, which commenced 11,700 years ago with the retreat of major glaciers. Transitioning to the Anthropocene would signify an acknowledgment that recent, human-induced alterations to geological conditions have been significant enough to mark the conclusion of the Holocene.
The decision would influence the language used in textbooks, research papers, and museums globally, shaping how scientists interpret our ongoing era for potentially generations or even millennia to come. Ultimately, however, the committee members tasked with voting on the Anthropocene in the past month not only assessed the significance of this epoch for the planet but also deliberated on the exact commencement of this period.
According to the definition proposed by a previous panel of experts, the Anthropocene began in the mid-20th century with the scattering of radioactive fallout from nuclear bomb tests. However, several members of the scientific committee, who recently evaluated this proposal, found this definition too narrow and uncomfortably recent to serve as a suitable marker for humanity’s profound impact on Earth.
Jan A. Piotrowski, a committee member and geologist at Aarhus University in Denmark, expressed, “It constrains, it confines, it narrows down the entire significance of the Anthropocene.” He questioned, “What about the onset of agriculture? What about the Industrial Revolution? What about the colonization of the Americas and Australia?”
“Human impact extends far back into geological time,” remarked another committee member, Mike Walker, an earth scientist and professor emeritus at the University of Wales Trinity Saint David. “To overlook this is to disregard the genuine, profound impact that humans have had on our planet.”
Several hours following the circulation of the voting results within the committee early Tuesday, some members expressed surprise at the significant margin of votes against the Anthropocene proposal compared to those in favor: 12-4, with two abstentions.
As of Tuesday morning, it remained unclear whether the results constituted a definitive rejection or if they could potentially be contested or appealed. Jan A. Zalasiewicz, the committee’s chair and a geologist at the University of Leicester, mentioned in an email to the Times that there were “some procedural issues to consider” but declined to elaborate further. Zalasiewicz, who supports formalizing the Anthropocene, is involved in the debate.
This issue of how to place our era within the broader narrative of Earth’s history has brought the typically obscure realm of geological chronology into an unusual spotlight.
The International Union of Geological Sciences, comprised of scientists, oversees the establishment of the grandly named chapters in our planet’s history. Using stringent criteria, this organization determines the beginning of each chapter and its defining characteristics. The objective is to maintain consistent global standards for articulating the history of the planet.
Geoscientists acknowledge that our current era distinctly stands out within the extensive history of the Earth. The remnants of modern civilization, such as radionuclides from nuclear tests, plastics, industrial ash, concrete, metal pollutants, rapid greenhouse warming, and a notable rise in species extinctions, are leaving unmistakable traces in the mineral record, particularly since the mid-20th century.
However, for the Anthropocene to warrant its own inclusion in the geologic time scale, it must be precisely defined to meet the criteria set by geologists. This definition may not necessarily align with the perspectives of anthropologists, artists, and others who are already using the term.
Several experts, skeptical about formally establishing the Anthropocene, emphasized that the vote against it should not be interpreted as a referendum among scientists regarding the overall state of the Earth. “This was primarily a narrow, technical matter for geologists,” said Erle C. Ellis, an environmental scientist at the University of Maryland, Baltimore County, who is among the skeptics. “This decision doesn’t discount the evidence of human-induced changes to the planet,” Ellis added. “The evidence continues to accumulate.”
Francine M.G. McCarthy, a micropaleontologist based at Brock University in St. Catharines, Ontario, stands as an advocate rather than a skeptic. She played a pivotal role in advancing the research endorsing the formal recognition of the Anthropocene epoch.
“Regardless of where we draw the line on the geological time scale, we are undeniably situated within the Anthropocene,” McCarthy emphasized. “Our only viable course of action is to embrace this reality and adjust our behavior accordingly.”
In 2009, the inception of the Anthropocene proposal began with the formation of a working group tasked with evaluating whether recent planetary transformations warranted inclusion in the geological timeline. Over several years of intensive study and discussion, the group, which later welcomed McCarthy, Ellis, and approximately three dozen others, concluded that indeed they did. Additionally, they determined that the most suitable starting point for this new epoch was around 1950.
Following this decision, the group faced the challenge of selecting a physical location that would prominently demonstrate a clear departure from the Holocene into the Anthropocene. Eventually, they settled on Crawford Lake in Ontario. Its deep waters have meticulously preserved detailed records of geochemical alterations within the sediment layers, making it an ideal site for delineating the transition between epochs.
In autumn of the previous year, the working group formally presented its proposal for the Anthropocene to the initial of three governing committees operating under the International Union of Geological Sciences. The proposal requires a sixty percent approval from each committee to progress to the subsequent stage.
The first committee, known as the Subcommission on Quaternary Stratigraphy, commenced voting on the proposal in early February. (Stratigraphy involves the study of rock layers and their temporal relationships, while the Quaternary represents the current geological period that commenced 2.6 million years ago.)
According to the principles of stratigraphy, every segment of Earth’s timeline necessitates a distinct and universally applicable starting point. The Anthropocene working group advocated for the mid-20th century as it encapsulated the surge in postwar economic expansion, globalization, urban development, and energy consumption. However, some members of the subcommission argued that humanity’s significant impact on the planet is a complex and widespread narrative, possibly lacking a singular commencement date that applies uniformly across all regions of the globe.
Hence, Walker, Piotrowski, and other proponents advocate for characterizing the Anthropocene as an “event” rather than an “epoch.” Within geological terminology, events carry a more flexible connotation. They do not feature on the formal timeline, and their commencement dates do not require approval from committees.
However, numerous pivotal occurrences in the planet’s history are labeled as events, such as mass extinctions, sudden bursts of biodiversity, and the oxygenation of Earth’s atmosphere 2.1 billion to 2.4 billion years ago.
Even if the subcommission’s decision rejects the Anthropocene proposal, the possibility remains for the new epoch to be incorporated into the geological timeline at a later stage. However, this would necessitate restarting the entire process of deliberation and voting.
As time progresses, evidence of our civilization’s impact on Earth will persistently accumulate within the geological record. The responsibility of deciphering its significance and integrating it into the broader narrative of history may eventually rest upon the future stewards of our planet.
Piotrowski emphasized, “Our influence is indelibly etched into the geological record, destined to be discernible in the future—this is unequivocal. It will be the task of future generations to determine its significance.”
