Has the human transformation of nature become significant enough to constitute a new geological epoch? Scientists think so. The “Anthropocene,” the term for this new era, has gained increasing scientific purchase over the past fifteen years. On Monday, the 35-member Working Group of the International Geological Congress recommended the formal adoption of a new epoch. The Anthropocene is said to have begun in the mid-twentieth century when the acceleration of human impacts on the Earth’s climate and chemistry marked a break from the 11,700-year Holocene. Final approval of the Working Group’s recommendation will take a few years, but the evidence backing it up is clear—from the appearance of micro-plastics in sediment to reflections of rising CO2 emissions in ice cores to traces of nuclear bomb explosions in coral. The Holocene set the conditions for the formation of civilization, and we will need new ways of thinking and acting for the human project to flourish under the conditions of an earth altered by our own hand.