The Anthropocene (pronounced an-thruh-puh-seen) epoch refers to an unofficial unit of geological time that describes the most recent chapter in our planet’s history. During this time, human activity has had a significant impact on the planet’s climate and ecosystems, via increased fossil fuel consumption, nuclear weapons tests and deforestation. The proposal to formally adopt the Anthropocene as a new epoch must pass the Subcommission on Quaternary Stratigraphy, which is responsible for subdividing Earth’s history from the past 2.4 million years. The proposal must then pass a vote at the larger International Commission on Stratigraphy before being ratified at the International Geological Congress in South Korea next year. Some geologists have expressed concern about adopting a new chapter in Earth’s history, describing the Anthropocene as an event, rather than a formal epoch. Until the new terminology is endorsed, we are still in the Holocene epoch, which began nearly 12,000 years ago.