The Anthropocene Is Not an Epoch: What Geologists Decided in March 2024 and Why

In March 2024, geologists formally rejected the proposal to designate the Anthropocene as a new epoch on the Geologic Time Scale. While the term remains widely used to describe human-driven planetary change, the decision reflects strict stratigraphic requirements and the diachronous nature of human impact, leading to discussions about framing it as a geological "event" instead.

David Grossman

June 16, 2026 · Updated October 19, 2026 · 4 min read

In March 2024, geologists formally closed a fifteen-year debate: the Anthropocene will not be added to the Geologic Time Scale as a new epoch. The Subcommission on Quaternary Stratigraphy (SQS), part of the International Commission on Stratigraphy (ICS), voted to reject the proposal, and the International Union of Geological Sciences (IUGS) approved that decision on March 26, 2024. The term itself remains widely used—but as an informal description of human-driven planetary change, not as a formal unit of geological time.

What Is the Anthropocene? Defining Humanity's Geological Impact

The Anthropocene is a proposed term for a period in which human activity—industrialization, resource extraction, habitat destruction, and the chemical transformation of atmosphere and oceans—leaves a detectable mark on Earth's strata. The Natural History Museum in London describes the underlying question as stratigraphic: whether our impact will be visible in the fossil record millions of years from now, and whether a single marker could separate this period from the Holocene, the epoch that began roughly 11,700 years ago.

That framing matters, because the debate was never about whether humans are reshaping the planet. It was about whether that reshaping fits the strict rules geologists use to divide deep time. Informally, "Anthropocene" already appears across the sciences and humanities as shorthand for an age of human dominance. The question before the ICS was whether it deserved a formal place on the International Chronostratigraphic Chart.

The Formal Process of Geological Time Classification

Formal geological time units are not declared by consensus; they are ratified. The ICS oversees the International Chronostratigraphic Chart, and any new epoch requires a proposal demonstrating both a stratigraphic basis and utility for geoscientists. The Anthropocene Working Group (AWG) of the SQS spent years preparing exactly such a proposal, seeking to establish the Anthropocene as a new chronostratigraphic series and corresponding epoch within the Geologic Time Scale.

The central requirement is a "golden spike"—formally a Global Boundary Stratotype Section and Point—a physical reference in rock layers that marks the boundary between two time units. As the Natural History Museum explains, such a marker must be significant enough to remain detectable in strata thousands or millions of years into the future. This demand for a single, globally synchronous signal became the crux of the entire dispute.

Epoch vs. Event: A Comparison of Classification Frameworks

The two proposals answer different questions. The epoch proposal asked whether human impact warrants a new formal division of geological time; the event proposal asks only how best to describe that impact. The table below compares them across the four dimensions that drove the SQS vote.

Comparing the formal Anthropocene epoch proposal with the geological "event" alternative
Dimension	Formal Epoch Proposal (Rejected)	Geological "Event" Alternative
Definition	A new chronostratigraphic unit within the Geologic Time Scale, marked by a specific global stratigraphic signal.	A time-transgressive, ongoing period of human-induced change to Earth systems, without rigid boundaries.
Formal Status	Required ratification by the ICS and IUGS; the SQS, a body under the ICS, rejected it in March 2024.	Informal; requires no ratification by stratigraphic bodies to be scientifically recognized or discussed.
Start Date	A fixed date—mid-20th century, exemplified by the 1952 plutonium spike—anchored by a "golden spike" at a specific site.	No single fixed start; onset varies regionally and temporally with the human impacts considered.
Implications for the Time Scale	Would have added a new, distinct unit to the official Geologic Time Scale, altering the formal geological record.	Recognizes human impact without changing the formal structure of the Geologic Time Scale.

Read together, the rows show why the vote went as it did: the epoch proposal's defining strength—a precise, globally synchronous boundary—was precisely what critics found unrepresentative of a sprawling, uneven process. The event framework keeps the descriptive power while discarding the requirement that failed.