Simon Lewis is Professor of Global Change Science at University College London and the University of Leeds. His research focuses on how humans are changing Earth as a system, with a focus on the tropics. A plant ecologist by training, he gained his PhD in Amazon rainforest ecology from Cambridge University, and was a Royal Society Research Fellow for 10 years. His recent scientific findings include discovering the world’s largest tropical peatland – as large as England – in central Congo. He advises several African governments on forest and climate science and related policy. With Mark Maslin he is author of The Human Planet: How We Created the Anthropocene (Penguin books/Yale University Press).