Daniel Schrag is the director of Harvard's Center for the Environment and is a professor of earth and planetary sciences at Harvard University. Schrag, who studies climate and climate change over the broadest range of Earth's history, has examined changes in ocean circulation over the last several decades, with particular attention to El Niño and the tropical Pacific. He also has worked on theories for Pleistocene ice-age cycles, including a better determination of ocean temperatures during the Last Glacial Maximum, 20,000 years ago. Currently, he is working with economists and engineers on technological approaches to mitigating future climate change. Schrag received a PhD in geology from the University of California at Berkeley.