**Julia Adeney Thomas **is Associate Professor of History at the University of Notre Dame.Mark Williamsis Professor of Palaeobiology at the University of Leicester and co-director of the International Laboratory for Palaeobiology and Palaeoenvironments at Yunnan University.Jan Zalasiewicz is Profess...

**Julia Adeney Thomas **is Associate Professor of History at the University of Notre Dame.Mark Williamsis Professor of Palaeobiology at the University of Leicester and co-director of the International Laboratory for Palaeobiology and Palaeoenvironments at Yunnan University.Jan Zalasiewicz is Professor of Palaeobiology at the University of Leicester and Chair of the Anthropocene Working Group of the International Commission on Stratigraphy.