The term “Anthropocene” describes a proposed new geological epoch, signaling a time when human activities have become the primary influence shaping Earth’s geology and ecosystems. This concept underscores humanity’s profound and widespread impact on the planet, marking a departure from natural geological forces as the dominant shapers of our world.
Understanding the Anthropocene
The word “Anthropocene” is derived from Greek roots: “anthropos” (human) and “cene” (new or recent). The concept gained recognition around 2000, largely due to atmospheric chemist Paul J. Crutzen and ecologist Eugene F. Stoermer.
They proposed that human activities have reached a scale comparable to natural geological forces, fundamentally altering Earth’s systems. This differentiates the Anthropocene from the Holocene Epoch, which began about 11,700 years ago. While the Holocene was characterized by stable natural influences, the Anthropocene posits a period where human dominance over these processes is undeniable.
Human Signatures on Earth
Scientists identify the Anthropocene through distinct “human signatures” preserved within geological strata. One prominent signature is the dramatic increase in greenhouse gas concentrations, particularly carbon dioxide and methane, resulting from the burning of fossil fuels and widespread deforestation. These gases are altering Earth’s atmosphere and climate.
Widespread pollution also leaves a clear mark, with plastic accumulation in oceans and on land, along with persistent organic pollutants and heavy metals, becoming pervasive in environmental records. Radionuclides from atomic bomb tests, especially from the mid-20th century, provide a globally identifiable marker in geological layers.
Massive land use changes, including extensive deforestation, urbanization, and agricultural expansion, have led to distinctive sediment layers and unprecedented rates of biodiversity loss. These changes include significant increases in erosion and sediment transport associated with human development. The proliferation of non-native species globally also contributes to unique paleontological signatures in recent deposits, distinct from past records of biotic change.
Debating its Geological Recognition
While the concept of the Anthropocene is widely discussed and accepted as a descriptor of human impact, its formal recognition as an official geological epoch by the International Commission on Stratigraphy (ICS) remains a subject of ongoing debate. The Anthropocene Working Group (AWG), established in 2009 by the Subcommission on Quaternary Stratigraphy (SQS) of the ICS, has been dedicated to investigating the Anthropocene as a geological time unit.
The AWG has worked to gather evidence and propose a “golden spike,” or Global Boundary Stratotype Section and Point (GSSP), which is an internationally agreed-upon reference site marking the beginning of a new geological period in rock layers. A key point of contention in the scientific community has been the proposed start date for the Anthropocene. Some suggestions include the early industrial revolution, while others favor the mid-20th century “Great Acceleration,” marked by the global spread of radionuclides from nuclear fallout.
The AWG proposed Crawford Lake in Canada as a potential GSSP, with a proposed start date of 1952 CE, based on a sharp increase in plutonium levels. However, in March 2024, the AWG’s proposal for an Anthropocene Epoch was rejected by the SQS, largely due to concerns about its shallow sedimentary record and recent proposed start date. Despite this formal rejection, the term “Anthropocene” continues to highlight the profound and enduring reality of human influence on Earth’s systems, regardless of its official stratigraphic status.