Giorgos Kallis is an ecological economist, political ecologist, and Catalan Institution for Research and Advanced Studies (ICREA) Professor at the Institute of Environmental Science and Technology, Barcelona. He is the author of Limits: Why Malthus Was Wrong and Why Environmentalists Should Care (Stanford University Press, 2019) and The case for Degrowth (Polity Press, 2020). He was previously a Marie Curie Fellow at the Energy and Resources group at the University of California, Berkeley, and he holds a PhD in Environmental Policy from the University of the Aegean, an MSc in Economics from Universitat Pompeu Fabra, and an MSc in Environmental Engineering and a Bachelors in Chemistry from Imperial College, London.