The Anthropocene, the idea that humanity has pushed Earth into an entirely new geological epoch, is not officially recognized. In March 2024, the Subcommission on Quaternary Stratigraphy voted against the proposal to formalize the Anthropocene as a new epoch, and the International Union of Geological Sciences subsequently confirmed that decision.1Earth’s Future. The Anthropocene Is More Than a Time Interval The rejection caught many people off guard, given how widely the term has spread through science, policy, and popular culture since atmospheric chemist Paul Crutzen popularized it around the year 2000. But the story of why it was rejected, what it would have meant to formalize it, and what alternatives remain on the table tells you more about our relationship with the planet than the word itself ever could.
What Making It Official Would Have Required
Geological time is not divided casually. To add a new epoch to the official timescale, geologists need physical evidence locked in rock, ice, or sediment that marks a clear global boundary. The gold standard is something called a “golden spike,” formally known as a Global Stratotype Section and Point, or GSSP. This is a specific location in the world where you can point to a layer and say: below this line is the old epoch, and above it is the new one. Defining the Anthropocene as a formal epoch required both a near-permanent shift in Earth’s trajectory and a correlative boundary marker recorded in stratigraphic deposits worldwide.2The Anthropocene Review. A transparent framework for defining the Anthropocene Epoch
The Anthropocene Working Group, a team of researchers tasked with building the case, spent over a decade assembling evidence and eventually proposed Crawford Lake in Ontario, Canada, as the candidate golden spike site. The lake’s sediments preserve remarkably thin annual layers, and those layers record a sharp mid-twentieth-century uptick in spheroidal carbonaceous particles from fossil fuel burning, along with plutonium isotopes from nuclear weapons testing.3PubMed Central. The varved succession of Crawford Lake, Milton, Ontario, Canada as a candidate Global boundary Stratotype Section and Point for the Anthropocene series In a small Canadian lake, the fingerprints of atomic bombs and coal plants converge in a single visible band of mud. It is a striking piece of evidence, but the broader geological community found the overall case insufficient.
Why Geologists Said No
The rejection was not a statement that humans have not transformed the planet. Nobody disputes that. The disagreement was about whether squeezing humanity’s sprawling, uneven impact into the rigid format of a geological epoch makes scientific sense.
One central problem is timing. Human influence on the planet did not flip on like a switch. Ancient deforestation, agriculture, irrigation, and the extinction of large animals all left marks in the geological record thousands of years before the mid-twentieth century. Soils altered by farming, for instance, fail to meet many of the criteria for establishing golden spikes: their preservation is poor, they do not appear in every important stratigraphic environment, and there is no clean way to identify where the base of a human-altered soil layer begins and natural soil ends.4The Holocene. The stratigraphic status of the Anthropocene A formal epoch pinned to 1950 would capture the nuclear and industrial signals beautifully, but it would leave millennia of earlier human transformation outside the boundary, creating an awkward mismatch between the concept and the label.
Critics also argued that the diachronic nature of human impacts, the fact that they appeared at different times in different places, is fundamentally at odds with the way epochs work. An epoch needs a synchronous global start. Human transformation of the environment was anything but synchronous: it began with megafauna extinctions tens of thousands of years ago in some regions, with the rise of agriculture roughly ten thousand years ago in others, and with industrialization only a few centuries ago in still others.5Journal of Quaternary Science. The Anthropocene as an Event, not an Epoch
Competing Ideas About When the Anthropocene Began
The debate over a start date was never settled, and the competing proposals reflect genuinely different views of what “human impact” means at a planetary scale.
The earliest candidate goes back thousands of years. William Ruddiman’s early anthropogenic hypothesis argues that ancient farming, particularly rice irrigation and deforestation, altered atmospheric methane and carbon dioxide concentrations during the late Holocene, preventing the natural cooling that orbital cycles would have produced. His analysis found that disproportionate biomass burning and rice cultivation could explain the methane anomaly, though early deforestation accounted for only about a quarter of the CO₂ anomaly.6Reviews of Geophysics. The early anthropogenic hypothesis: Challenges and responses This is a provocative idea, and while it has been challenged on multiple fronts, it has held up well enough to remain part of the conversation.
A more dramatic mid-range candidate is 1610, a date tied to the aftermath of European colonization of the Americas. The decimation of Indigenous populations across Central and South America led to massive land abandonment and a reforestation event that pulled enough carbon dioxide from the atmosphere to produce a measurable dip, which some researchers call the “Orbis Spike.”7Journal of the American Musicological Society. Songs of the New World and the Breath of the Planet at the Orbis Spike, 1610: Toward a Decolonial Musicology of the Anthropocene This date has the virtue of being tied to a specific geochemical signal, but it is also entangled with the horrors of colonialism, which makes it conceptually loaded in ways that geological boundaries usually are not.
The proposal that the Anthropocene Working Group ultimately put forward centered on the mid-twentieth century, around 1950. This is the era researchers call the Great Acceleration, a sharp upturn in a wide array of socioeconomic indicators and Earth System trends.8Episodes. The Great Acceleration is real and provides a quantitative basis for the proposed Anthropocene Series/Epoch Population growth, energy use, fertilizer consumption, ocean acidification, tropical forest loss, and atmospheric greenhouse gas concentrations all bent upward steeply after World War II. From an Earth System science perspective, only beyond the mid-twentieth century is there clear evidence for fundamental shifts in the state and functioning of the planet that go beyond anything seen during the Holocene.9The Anthropocene Review. The trajectory of the Anthropocene: The Great Acceleration The plutonium fallout from nuclear testing provided a clean, globally synchronous marker in sediment layers, making the mid-century date the most stratigraphically defensible option. But even this strong case was not enough to win the vote.
The Event Alternative
The rejection of a formal epoch has not killed the concept. Instead, it has redirected the conversation toward an alternative framing that many geologists had been advocating for years: treating the Anthropocene as a geological event rather than an epoch.
The distinction matters more than it sounds. Geological events can be long, overlapping, and spatially uneven. They do not need a single start date pinned to a golden spike. An ice age is an event. A mass extinction is an event. These things unfold over varying timescales and affect different regions at different times, which is exactly how human transformation of Earth has played out. Defining the Anthropocene as an event would incorporate a far broader range of transformative human cultural practices and be more readily applicable across academic fields than a fixed epochal definition, while still allowing for a robust stratigraphic characterization.10Episodes. A practical solution: the Anthropocene is a geological event, not a formal epoch
Event stratigraphy, a tool already used for deep-time geological changes, has been proposed as a way to formalize the Anthropocene concept using analogous past events as templates.11Earth-Science Reviews. Epochs, events and episodes: Marking the geological impact of humans Under this framework, the Anthropocene would not need one clean line in the rock record. It could encompass the scattered, overlapping pulses of human influence stretching from ancient megafauna extinctions to the industrial revolution to the Great Acceleration. For many researchers, this feels like a more honest description of reality than trying to pick a single date.
Where We Officially Stand on the Geological Clock
Without a formal Anthropocene, the official epoch we live in remains the Holocene, which began roughly 11,700 years ago at the end of the last ice age. The Holocene was recently subdivided into three stages: the Greenlandian (early), the Northgrippian (middle), and the Meghalayan (late and current), each with its own formally ratified golden spike.12Episodes. Formal ratification of the subdivision of the Holocene Series/Epoch The Meghalayan stage, which we are technically living in, began around 4,250 years before 2000 CE, its boundary coinciding with a global drought event linked to weakened Asian monsoon patterns.13Quaternary Science Reviews. Exact dating of the Meghalayan lower boundary based on high-latitude tree-ring isotope chronology
This creates a peculiar situation. We are formally living in the Meghalayan stage of the Holocene epoch, a subdivision defined by a drought that started around 2250 BCE. Meanwhile, the planet’s atmosphere, oceans, soils, and biological communities have been altered by human activity to a degree that may dwarf any change since the end of the Pleistocene. The geological timescale, which is supposed to mark the most significant shifts in Earth’s history, does not yet have a label for what is arguably the most significant ongoing shift.
The Physical Evidence That Will Not Go Away
Whatever the formal classification ends up being, the physical markers of human impact are accumulating in the geological record at a pace that will be readable for millennia or longer.
Microplastics are a striking example. They are now ubiquitous in sediment layers worldwide, and researchers have begun using them as a kind of dating tool, a “technofossil.” Different plastic types appeared in manufacturing at known dates, and the sequence in which they show up in sediment cores matches published ages, meaning microplastics could eventually help date sedimentary layers on a centennial scale.14Anthropocene Coasts. Are microplastics the ‘technofossils’ of the Anthropocene? Future geologists, if they exist, will find plastic layered into rock the way we find fossil shells from ancient seas.
Nutrient cycling tells a similar story. Human activities have tripled the global mobilization of phosphorus across the land-water continuum and increased phosphorus accumulation in soil by roughly seven teragrams per year. About 30% of atmospheric phosphorus transfer is now caused by human activities, a larger share than previously estimated.15PubMed. Human Perturbation of the Global Phosphorus Cycle: Changes and Consequences For nitrogen, the picture is equally stark: even in the most optimistic scenarios of rapidly increasing agricultural efficiency, the global nitrogen balance and associated losses through ammonia, leaching, and denitrification will not decrease from current levels.16Global Biogeochemical Cycles. Human alteration of the global nitrogen and phosphorus soil balances for the period 1970–2050 These are not subtle perturbations. They are wholesale rewrites of the planet’s chemical plumbing, and they leave signatures in sediment and ice that will persist long after the policies that created them are forgotten.
Then there is the biomass question. The total mass of mammals on Earth is now overwhelmingly dominated by livestock and humans. Livestock alone account for an estimated 630 megatons of carbon, humans for roughly 390 megatons, dwarfing the biomass of all wild mammals combined.17PubMed Central. The global biomass of wild mammals Step back and look at Earth from that vantage: most of the mammalian flesh on the planet is either us or animals we raise to eat. That is not a trend that hides in the geological record.
The Deeper Past of Human Impact
One reason the Anthropocene debate resists a tidy resolution is that human impact did not begin with factories. The extinction of megafauna during the late Quaternary, a wave of large-animal losses that swept across continents as human populations expanded, represents what researchers have called the first planetary-scale, human-driven transformation of the environment.18Anthropocene. Megafauna extinctions in the late-Quaternary are linked to human range expansion, not climate change Large animals play outsized roles in shaping vegetation, dispersing seeds, and cycling nutrients. Their loss did not just remove species; it restructured ecosystems on every inhabited continent.
This deep prehistory of human impact is part of what made the mid-twentieth-century boundary so contentious. Supporters of the Great Acceleration date argued, reasonably, that a formal geological boundary needs a sharp, globally synchronous signal, and the mid-century markers deliver that. Critics countered, also reasonably, that an Anthropocene starting in 1950 implies humanity was geologically irrelevant before then, which anyone familiar with deforestation, agriculture, or megafauna loss knows is absurd. Both sides had valid points, and the tension between them is one reason the vote went the way it did.
Capitalocene, Plantationocene, and the Politics of Naming
Outside the world of stratigraphy, the Anthropocene concept has sparked a different kind of debate: who exactly is the “anthropos” responsible?
The term implies that humanity as a whole drove the planet into a new state. But historians, social scientists, and environmental humanities scholars have pushed back hard on that framing. Marxist environmental historian Jason W. Moore has argued for replacing the Anthropocene with the “Capitalocene,” a term that points to capital accumulation, not humanity in general, as the causal force behind planetary disruption.19The Anthropocene Review. From the Anthropocene to the Capitalocene and beyond The argument is that a subsistence farmer in sub-Saharan Africa and an industrial conglomerate in North America have not contributed equally to atmospheric carbon or ocean acidification, and a term that lumps them together under “human” obscures the political and economic structures that produced the crisis.
A related concept, the “Plantationocene,” has gained traction in the environmental humanities as a way to foreground the role of colonial plantation systems, forced labor, and monoculture agriculture in reshaping global ecosystems.20Geography Compass. Anthropocene, Capitalocene, … Plantationocene?: A Manifesto for Ecological Justice in an Age of Global Crises These are not just academic rebranding exercises. The name you choose shapes which causes you highlight and which solutions seem plausible. If the problem is “humans,” the answer might be technology and efficiency. If the problem is capitalism, the answer looks more like structural economic reform. If the problem is plantation colonialism, the answer centers justice and reparation.
None of these alternative names are competing for a spot on the geological timescale. They operate in a different intellectual register, one concerned with causation and responsibility rather than stratigraphy. But they have become inseparable from the broader Anthropocene conversation, especially in fields that deal with climate policy and environmental governance.
What Happens to the Word Now
The formal rejection has left the Anthropocene in an unusual position. It is arguably the most widely recognized geological term coined in the last century, used across thousands of scientific papers, policy documents, museum exhibitions, art installations, and book titles. Yet it has no official standing on the geological timescale. Researchers who championed the concept have argued that the opportunity now arises to reset the definition of the Anthropocene, decoupling it from the rigid requirements of epoch classification and allowing it to function more flexibly as a descriptor of human-driven planetary change.1Earth’s Future. The Anthropocene Is More Than a Time Interval
In practice, this probably means the Anthropocene will continue to be used informally in much the same way it has been for two decades: as a shorthand for the observation that human activity has become a geological force. Scientists will still publish papers on Anthropocene stratigraphy, Anthropocene ecology, and Anthropocene governance. The word is not going to disappear from textbooks or public discourse. What it will lack is the imprimatur of the International Commission on Stratigraphy, which means it will not appear on the official geologic timescale chart that hangs in geology classrooms around the world.
For most people who encounter the term, that distinction will not matter much. The Anthropocene’s power was always more conceptual than bureaucratic. It gave people a way to talk about the scale of what humanity has done to the planet, a framework that connected carbon emissions to microplastics to species extinction to nitrogen runoff under a single recognizable banner. Whether it sits on a formal chart or not, that framework is doing real intellectual and political work, and the geological evidence it points to is only growing thicker in the sediment with each passing year.