We are living astride two epochs in geological time. The first, the Holocene, began about 11,700 years ago; the second, the Anthropocene, now defines our troubled present. In a 2002 article, the Nobel laureate Paul Crutzen and Eugene Stoermer suggested that we have entered a new era in geological time called the Anthropocene epoch. This shift to a “human-dominated, geological epoch” is significant, according to Simon Lewis and Mark Maslin, because the “impacts of human activity” will be “observable in the geological stratigraphic record for millions of years to come.”