After 15 years of deliberation, the team of scientists disagreed on when exactly the new epoch, known as the Anthropocene, might have begun. This decision, announced by the International Union of Geological Sciences, the governing body of the field, has sparked allegations of misconduct and a lack of due process.

The proponents argued that humankind has profoundly altered the natural world, ushering in a new era. They listed soaring greenhouse gases, the proliferation of microplastics, the devastation of other species, and the consequences of nuclear tests as evidence supporting the notion that the Anthropocene began in the mid-20th century. Traces of radioactive material found in sediment layers of lakes, widespread disruptions to plants and animals, and the omnipresence of "forever chemicals" were cited as further evidence.

However, those opposing the proposal highlighted that human influence on the planet predates the 1950s. Moments such as the transition to agriculture and the industrial revolution were cited as significant turning points in reshaping the Earth's landscape. The opponents argued that defining the start of the Anthropocene solely around the mid-20th century would not accurately capture the long history of humanity's impact.

The voting committee ultimately rejected the proposal, with four votes in favor, 12 against, and three abstentions. The International Union of Geological Sciences supported the decision, describing it as a "decisive rejection" by the field's leading experts. Despite the rejection, the term Anthropocene will continue to be widely used as a descriptor of human impact on the Earth system.

Martin Head, a professor of earth sciences at Brock University in Canada, who advocated for the Anthropocene, expressed disappointment with the outcome, calling it a missed opportunity to recognize the reality of Earth's altered state. Meanwhile, Erle Ellis, a professor of geography and environmental systems at the University of Maryland, acknowledged that the age of man has brought significant planetary changes but questioned whether these changes constituted an epoch that began only seven decades ago.

The decision not to recognize the Anthropocene as a formal unit in the Geologic Time Scale is final, as there is no avenue for appeal. Though this outcome may disappoint some, the debate surrounding the concept will likely continue as scientists strive to better understand and characterize the profound impact of humanity on our planet.