Scientists Call for a Stable Definition of the Anthropocene Epoch

A team of leading geologists, historians, social scientists and legal scholars is urging the global research community to settle on one clear, stable definition of the Anthropocene, arguing that the term’s explosive spread across the sciences, humanities and arts has produced a tangle of incompatible meanings that now undermines both research and policy. In a new Perspective published in Nature Reviews Earth & Environment, more than thirty authors, coordinated by Jan Zalasiewicz of the University of Leicester, contend that the Anthropocene is best understood in its original sense: a geological epoch defined by humanity’s decisive departure from the relatively stable planetary conditions of the Holocene, with its base placed at 1952, the onset of the mid-twentieth-century Great Acceleration.

The Anthropocene concept was coined in recognition that human activities have ended the unusually benign environmental regime that characterized the Holocene, the epoch that encompassed the entire history of agriculture, cities and written civilization. But as the term migrated from stratigraphy into economics, politics, museum curation, education and the arts, it accumulated divergent and sometimes contradictory definitions. Some scholars stretch the Anthropocene back thousands or even tens of thousands of years to capture the cumulative footprint of early farming, mining and land clearance. The authors argue that while such extended interpretations portray the totality of anthropogenic change, they obscure the quantitatively established, dramatic rupture in Earth system behavior that began in the mid-twentieth century, and they cannot be defined in formal chronostratigraphic terms.

The technical case for the 1952 boundary rests on the stratigraphic record. Sediments deposited from the mid-twentieth century onward carry a distinctive and globally synchronous suite of signals: radionuclide fallout from atmospheric nuclear weapons testing, spheroidal carbonaceous fly-ash particles from fossil fuel combustion, a sharp rise in plastics and microplastics, and profound shifts in fossil assemblages driven by global species translocations and industrial agriculture. High-resolution analyses of archives such as the varved sediments of Crawford Lake in Canada have demonstrated that these markers appear together within a narrow time window, providing the kind of precise, correlatable geological evidence that formal epoch boundaries require. Human-driven environmental change of earlier millennia, by contrast, is diachronous and regionally variable, leaving no single globally synchronous horizon.

The authors emphasize that the distinction is not merely academic. A formally defined Anthropocene epoch enables quantitative and qualitative comparison between the stable Holocene and the increasingly unstable Anthropocene, a comparison already embedded in influential frameworks such as the planetary boundaries concept. That framework, which assesses how far humanity has pushed Earth system processes beyond safe operating limits, depends on a Holocene baseline against which modern departures can be measured. Six of nine planetary boundaries are currently judged to have been transgressed, and the annual Planetary Health Check tracks the deterioration. Without a stabilized Anthropocene definition, the authors warn, the conceptual foundation for such comparisons becomes blurred, weakening the scientific signal that policymakers most need to hear.

The Perspective also documents how deeply the Anthropocene idea has already penetrated institutions beyond geology. Dedicated research centers, policy programs and educational initiatives now bear its name. The United Nations Development Programme has framed new threats to human security in Anthropocene terms, the European Environment Agency has explored what it would mean to exit the Anthropocene, and the OECD’s PISA 2025 science framework incorporates agency in the Anthropocene as an educational goal. International law is grappling with the concept as well: the International Law Association’s committee on sea level rise has traced the implications of moving from Holocene assumptions of stable coastlines to an Anthropocene reality of rising seas, and the International Court of Justice issued a landmark advisory opinion on states’ obligations in respect of climate change in July 2025.

Underlying all of these applications is a single, consequential insight: the Earth system transformation of the Anthropocene is systemic, not piecemeal. Greenhouse gas accumulation, ocean warming and acidification, biodiversity loss, sediment cycle disruption, nutrient overloading and the spread of novel materials such as plastics and concrete are coupled processes, each amplifying the others. The authors argue that because the disruption is systemic, political responses must also be systemic rather than ad hoc. A unified Anthropocene epoch, they contend, would facilitate systematic, actionable climate and environmental policies by giving scientists, lawyers, economists and politicians a shared, precisely bounded reference point for what has changed and how quickly.

The geological evidence for that change is now overwhelming in its breadth. Humans have become the most significant global geomorphological driving force of the twenty-first century, moving more material than all natural erosion processes combined. The physical technosphere, the sum of human-made structures, machines and waste, has reached planetary scale, and its discarded products, from broiler chicken bones to concrete and plastics, are forming recognizable technofossils that will persist in the rock record. Earth’s sediment budget has been fundamentally reorganized, deltas and coastal wetlands are being transformed faster than they can adapt, and palaeontological signatures of the Anthropocene, including global species translocations and mass mortality assemblages, are demonstrably distinct from those of any previous epoch. Meanwhile, monitoring shows the acceleration continuing: record ocean temperatures in 2024, record-low Antarctic sea ice, warming-intensified drought, and documented declines in insect populations and wild mammal biomass.

The authors do not dismiss the value of broader, extended uses of the term. Environmental historians and archaeologists have shown that human reshaping of landscapes stretches back millennia, and understanding that deep history matters for questions of responsibility, equity and long-term change. But they insist that these interpretations represent a concept distinct from the Anthropocene epoch. Conflating the two, they argue, produces the worst of both worlds: the dramatic mid-twentieth-century rupture, which is the clearest and most politically urgent signal, gets diluted into a diffuse background of ancient impacts, while the genuine achievements of pre-industrial societies are recast as the origin of a crisis they did not cause. Clarity, they maintain, serves both scholarship and justice.

Looking forward, the Perspective maps out a research agenda in which a stabilized Anthropocene definition becomes a working tool across disciplines. In Earth science, it would sharpen the study of the anthropoclastic rock cycle, legacy contaminants re-released by melting glaciers, and the fate of microplastics as planetary markers. In law and governance, it would underpin efforts to adapt maritime boundaries, environmental obligations and international institutions to a planet no longer governed by Holocene assumptions. In education, it would anchor curricula that teach Earth system thinking and futures literacy. In the arts and humanities, it would provide a common chronological anchor for museums, exhibitions and imaginative work that seeks to make planetary change perceptible. The central purpose of a clear, formalized definition, the authors conclude, is to enable unified communication across the Earth sciences, social sciences, humanities, society and political and legal fora, so that the scale of the transformation can be grasped, debated and addressed with the seriousness it demands.

Subject of Research: Definition and interdisciplinary applications of the Anthropocene epoch

Article Title: Future directions for Anthropocene research and its applications

Article References: Zalasiewicz, J., Thomas, J. A., Cohen, K. M., Vidas, D., Sörlin, S., Waters, C. N., Head, M. J., Summerhayes, C. P., Leinfelder, R., Wallenhorst, N., Syvitski, J., McNeill, J. R., Robin, L., Williams, M., Cearreta, A., Ivar do Sul, J. A., Park, B. S., McCarthy, F. M. G., Han, Y., … Kuwae, M. (2026). Future directions for Anthropocene research and its applications. Nature Reviews Earth & Environment, 7(9), 633-646. https://doi.org/10.1038/s43017-026-00820-z

Image Credits: AI Generated

DOI: 10.1038/s43017-026-00820-z

Keywords: Anthropocene, Holocene, Great Acceleration, chronostratigraphy, planetary boundaries, Earth system science, Crawford Lake, technosphere, microplastics, geological epoch, environmental policy, international law