What the Anthropocene rejection reveals about scientific cultures

Author: José Luis Granados Mateo is a Postdoctoral Researcher in the Department of Logic and Philosophy of Science at the University of the Basque Country.

Two years ago, in March 2024, I wrote in this blog about a decision that surprised many: the rejection of the Anthropocene as a formal geological epoch. After fifteen years of work by an international team of experts, the proposal to declare that we are now living in a new chapter of Earth’s history—one defined by human impact—had been voted down by the Subcommission on Quaternary Stratigraphy.

At the time the debate was intense. Accusations of procedural irregularities circulated. The historian Naomi Oreskes described the vote as “a sham”. The International Union of Geological Sciences had to intervene to confirm that the process had followed its rules. Amid the controversy, one question stood out: should the Anthropocene be treated as a formal “epoch” with a single, precise start date, or as an ongoing “event” that unfolded at different moments across the planet?

Two years later, in 2026, the dust has largely settled. The official International Chronostratigraphic Chart has not changed: we remain in the Holocene. Yet new articles, conference sessions and books about the episode continue to appear. With some distance, we can now ask a different set of questions: what does this episode reveal about how science actually works? And why should anyone who is not a geologist care?

The clash that wouldn’t go away

The popular story of the Anthropocene is comforting: a brilliant scientist has a sudden insight, coins a powerful term, evidence accumulates, consensus emerges, and a new epoch is added to the geological timescale.

Reality proved more complicated. What unfolded was a deep clash between two scientific cultures, each shaped by its own history, values and standards of evidence.

One side was Earth System Science, a field that took shape in the 1980s around the idea that the planet operates as a single, interconnected system—oceans, atmosphere, biosphere and human activity all influencing each other. Its roots reach back to Cold War-era projects like the International Geophysical Year (1957–58), were strengthened by NASA’s search for a post-Apollo mission, and were institutionalised through large international programmes. Earth system scientists think in terms of global datasets, computer models and planetary boundaries. For them, the Anthropocene was evident: the hockey-stick curve of CO₂, plastic everywhere in the oceans, accelerating biodiversity loss. The Earth system had clearly shifted.

On the other side stood traditional stratigraphy, a discipline with nineteenth-century origins. Stratigraphers act as the custodians of deep time, maintaining a single, consistent global timeline so geologists anywhere can refer to the same moment in Earth history. To recognise a new epoch they demand a “golden spike” (a Global Boundary Stratotype Section and Point, or GSSP): a specific, accessible rock section where a change is recorded that is both global and synchronous (happening at the same time everywhere). These rules, refined over decades, prioritise stability, precision and international agreement.

The Anthropocene Working Group tried to bridge both worlds. It was unusually interdisciplinary—stratigraphers, Earth system scientists, historians and even a legal expert. They proposed a mid-twentieth-century start date marked by radionuclides from nuclear weapons tests and selected Crawford Lake in Canada as the reference site. For Earth system scientists this was logical: the planetary transformation was real, and the radioactive layer was simply one readable signal among many.

The stratigraphers, however, judged the proposal against narrower criteria: did it satisfy the established rules for a GSSP? Their answer was no.

Whose objectivity?

What struck me then—and still does—is how each side accused the other of straying from science.

Naomi Oreskes argued that by refusing to recognise what “we all can now see”, the stratigraphers risked damaging the credibility of science itself.

From the stratigraphers’ viewpoint the situation looked different. Years earlier, two of them had warned that the drive to formalise the Anthropocene was driven more by political and public resonance than by stratigraphic evidence. Visibility in policy circles, emotional weight, media attention—these factors, they felt, were influencing the process beyond the technical standards that had governed their field for generations.

Both groups claimed to defend objective science. Both believed the other was allowing external values to intrude. And both, I believe, were partly right—and partly missing the deeper point.

The philosopher Helen Longino offers a useful lens here. Objectivity, she argues, is not the absence of values (an impossible goal); it is the presence of procedures that expose ideas to criticism from diverse perspectives. The stratigraphers had their procedures: rigorous GSSP criteria, voting protocols, long-established consensus mechanisms. The Earth system scientists had theirs: interdisciplinary teamwork, attention to planetary-scale dynamics, concern for societal relevance.

The conflict was not science versus politics, nor pure objectivity versus bias. It was a clash between two legitimate but differently organised ways of producing trustworthy knowledge. The question “Is the Anthropocene real?” only makes sense once we add: “Real according to whose standards and practices?”

A forgotten alternative

In my earlier post I noted the idea—defended by some scholars—that the Anthropocene might be better understood as an ongoing geological event (like the spread of life onto land) rather than a sharply bounded epoch.

There is another angle worth recovering. In 1873 the Italian geologist Antonio Stoppani proposed ¹ an “Anthropozoic era”. He is occasionally cited as an early precursor to the modern concept, slotted into a linear story that leads to Paul Crutzen. But when we read Stoppani on his own terms, he offers something more valuable: a different way of imagining human impact.

Stoppani’s markers were not global geochemical spikes or planetary system shifts. They were material and archaeological: human bones, tools, buildings, settlements preserved in terrestrial deposits—caves, lake sediments, river deltas. He drew evidence mostly from Europe and openly acknowledged that extending the idea worldwide would require far more data. His “era” encompassed the entire span of human presence, not merely the decades since 1950.

Stoppani did not have our satellites, ice cores or global monitoring networks. Yet precisely because his imagination operated with different priorities and evidence, he serves as what the philosopher Hasok Chang calls a “diagnostic contrast”. Comparing his approach with ours helps us see the specific choices embedded in the contemporary Anthropocene concept.

Why do we privilege the global scale above all others? Why do we focus so heavily on predicting future trajectories rather than documenting the material traces of the past? Why do we anchor the concept in a thin layer of radioactive particles rather than in the dense accumulation of cities, mines, fields and landfills? These are not merely historical curiosities. They influence how we frame today’s environmental crisis and which responses we consider plausible.

What the debate tells us, two years on

In 2026 the stratigraphic rejection stands. No proposal to revisit the Anthropocene epoch has gained traction within the International Commission on Stratigraphy. Yet the concept itself has not faded—quite the opposite. In the social sciences, humanities and policy discussions it continues to thrive. Terms like Capitalocene (centring economic systems) and Plantationocene (highlighting colonial agriculture and slavery) have gained ground, each drawing attention to different drivers of planetary change.

The formal rejection may have done the concept a favour by releasing it from the strict requirements of one discipline. Freed from the need for a single golden spike, the Anthropocene has become a more flexible frame for thinking about humanity’s role on Earth.

The larger lesson, I think, concerns scientific authority itself. Authority is not a monolithic property that science either possesses or lacks. It is negotiated, distributed and sometimes contested across communities. The stratigraphers preserved control over the official geological timescale, but at the price of seeming disconnected from a powerful idea that had already entered public culture. The Earth system scientists saw their framing continue to shape research and debate even without formal recognition.

For everyone else—researchers in other fields, students, policymakers, concerned citizens—the episode reminds us that scientific categories are never simply “discovered” in nature. They are constructed through evidence, yes, but also through values, disciplinary traditions, institutional histories and contingent choices.

Recognising this does not weaken science. It makes the enterprise more transparent, more interesting—and more human.

The Anthropocene may never appear on the official chart. But it will keep shaping how we understand our place on the planet. And understanding why that is so tells us as much about science as it does about the Earth.

Acknowledgements: José Luis Granados Mateo’s research is supported by funding from the Basque Government’s Postdoctoral Research Program.

Further reading:

• Chang, H. (2012). Is Water H₂O? Evidence, Realism and Pluralism. Springer.
• Longino, H. (1990). Science as Social Knowledge. Princeton University Press.