Formerly, Houghton Lecturer, Massachusetts Institute of Technology. Currently, Frank J. Gilloon Professor of Environmental Science and Engineering and Director, Ronald and Maxine Linde Center for Global Environmental Science, California Institute of Technology; researches fundamental aspects of how the climate of the earth and other planets come about and may change. Named one of Top 20 Scientists under 40, Discover Magazine. David and Lucile Packard Fellow, Alfred P. Sloan Research Fellow and NASA Earth System Science Fellow. Recipient, James R. Holton Award, American Geophysical Union.