The Anthropocene: Why Geologists Rejected a Human Epoch

Many scientists say humans have changed Earth so profoundly that we now live in a new chapter of the planet’s history, which they call the Anthropocene. In 2024, the body that officially names geological time declined to recognize it. The word is still everywhere, and the story of how it was proposed, tested and turned down shows how geologists decide what counts as a new epoch.

What is the Anthropocene?

The Anthropocene is a proposed geological epoch defined by the global impact of human activity on Earth. Evidence cited by researchers includes fossil fuel burning, nuclear weapons detonations, and fertilizer and plastic dumped on land and in waterways. It is not currently an official unit of geologic time. Officially, the present time is still the Meghalayan Age of the Holocene Epoch, according to the International Commission on Stratigraphy.

Who coined the term Anthropocene?

Paul Crutzen and Eugene Stoermer coined the word in 2000, in the Global Change Newsletter. It joins Greek roots for human and new, following the naming pattern of earlier epochs. The idea spread quickly beyond geology into climate science, ecology, history and public debate.

How do geologists define a new epoch?

In stratigraphy, the study of rock layers, a unit of geologic time is anchored to a physical reference point in the rock record. That point is called a Global Boundary Stratotype Section and Point, or GSSP, informally a golden spike. A proposal needs evidence that is global, datable and preserved in layers that can be sampled. It must then pass votes by several committees.

What did the Anthropocene Working Group propose?

The Anthropocene Working Group (AWG) was part of the Subcommission on Quaternary Stratigraphy, which sits within the International Commission on Stratigraphy (ICS). Its work unfolded in steps:

• 2019: in a binding vote, 88 percent of votes cast supported treating the Anthropocene as a formal unit defined by a GSSP, and 88 percent supported a mid-20th-century primary guide for its base
• October 31, 2023: the group proposed an Anthropocene Series and Epoch and a Crawfordian Stage and Age, with the base set at 1952 CE
• Primary marker: a sharp upturn in plutonium, linked to artificial radionuclides from thermonuclear bomb tests in the early 1950s

The proposed start lined up with the mid-20th-century period of rapid growth in population, energy use and production that scientists call the Great Acceleration.

Why Crawford Lake?

The AWG chose Crawford Lake in Ontario, Canada, as the candidate GSSP. The lake outside Toronto is about 29 meters (79 feet) deep, and reporting on the proposal says it was chosen over 11 other sites because its sediment layers clearly preserve the annual effects of human activity. Its varved sediments, meaning layers laid down year by year, record nuclear fallout, pollution and rising temperatures, with distinct signals starting around 1950. The group named three auxiliary sites as backups: Beppu Bay in Japan, Sihailongwan Maar Lake in China and the Sniezka peatland in Poland.

The AWG also pointed to fly ash, plastics and concrete as examples of Anthropocene phenomena, sometimes described as new rocks and technofossils. These illustrate human influence, but the plutonium upturn was the formal marker.

What happened in 2024?

In March 2024, the ICS Subcommission on Quaternary Stratigraphy voted to reject the proposal for an Anthropocene Epoch as a formal unit of the Geologic Time Scale. The ICS executive and the International Union of Geological Sciences (IUGS) approved the vote. The public statement did not give a vote count, and it noted only that the voting members have extensive experience and wide expertise in Quaternary stratigraphy and chronology.

Is the term still used?

Yes. The IUGS statement says the term will nevertheless continue to be used by Earth and environmental scientists, as well as social scientists, politicians, economists and the public. It describes the word as an invaluable descriptor of human impact on the Earth system. In informal use, the Anthropocene links to topics such as climate change, which the Global Carbon Project tracks each year in its report on CO2 emissions, and to the plastic pollution now found in sediments and oceans.

Anthropocene vs. Holocene

The Holocene is the official epoch that began roughly 11,700 years ago after the last ice age, and the formal timescale still places us within it. The Anthropocene would be a break from that interval, with a start in the 1950s instead of 11,700 years ago. Critics of the 1950s date have argued that human power to transform the environment began much earlier; John Holdren, a former U.S. White House science adviser, said the start date was wrong and should be much earlier.

Why does the label matter if it is informal?

A geological name does more than classify rocks. It is a statement about what future geologists will see in layers formed today. The debate pushed researchers to ask what traces human activity leaves in sediment, including the residue of fossil fuel burning. That question stays scientifically useful even without a formal epoch.

Frequently asked questions

Is the Anthropocene an official epoch?

No. The proposal was rejected in March 2024, and the current official unit is the Meghalayan Age of the Holocene Epoch.

When did the Anthropocene supposedly begin?

The Working Group proposed 1952 CE, tied to a plutonium upturn from thermonuclear bomb tests.

Who coined the word?

Paul Crutzen and Eugene Stoermer, in 2000.

Will scientists keep using the term?

Yes. The IUGS itself says it will continue to be used informally.