Tim Lenton is the director of the Global Systems Institute and chair in climate change and Earth system science at the University of Exeter. His reading of James Lovelock’s books on Gaia, when he was an undergraduate, ignited his passion for studying the Earth as a whole system, forming the foundations of his research to date. For his Ph.D., he studied what regulates the nutrient balance of the ocean and the oxygen content of the atmosphere. In his first job he built a simple coupled carbon cycle and climate model and led the development of the Grid ENabled Integrated Earth system model, or GENIE.