Raymond T. Pierrehumbert is the Halley Professor of Physics at the University of Oxford, having previously served on the faculties of MIT, Princeton and the University of Chicago. His research has dealt with fluid mechanics, applied mathematics and the physics of climate. His mathematical research includes work on stability theory and on application of dynamical systems concepts to mixing by organized fluid motions. His work on physics of climate has covered climates of Mars and Titan, and of the response of Earth’s climate to human-caused increases in carbon dioxide, as well as recent and deep time past climates. He was a lead author of the IPCC Third Assessment Report. His present research is focused on climates of extrasolar planets, and their evolution over time. Pierrehumbert is the author of the textbook Principles of Planetary Climate, and is a Fellow of the American Geophysical Union and the American Academy of Arts and Sciences. He was named Chevalier de l’Ordre des Palmes Academiques by the Republic of France. He is a member of the Science and Security Board of the Bulletin of Atomic Scientists.