Ruth DeFries is a professor of ecology and sustainable development at Columbia University in New York. She uses images from satellites and field surveys to examine how the world’s demands for food and other resources are changing land use throughout the tropics. Her research quantifies how these land use changes affect climate, biodiversity and other ecosystem services, as well as human development. She has also developed innovate education programs in sustainable development. DeFries was elected as a member of the U.S. National Academy of Sciences, one of the country’s highest scientific honors, received a MacArthur “genius” award, and is the recipient of many other honors for her scientific research. In addition to over 100 scientific papers, she is committed to communicating the nuances and complexities of sustainable development to popular audiences, most recently through her book “The Big Ratchet: How Humanity Thrives in the Face of Natural Crisis.”