Professor Wofsy’s scientific work spans the broad range of processes affecting the chemistry of the atmosphere, including pioneering work on determining regional emissions of carbon dioxide and methane from ground based, aircraft, and remote sensing measurements. His studies aim to understand under- lying causes for change in atmospheric composition, in order to mitigate human impacts and to help provide scientific information for wise societal decisions. He is a member of the National Academy of Sciences and recipient of the Revelle Medal of the American Geophysical Union and NASA's Distinguished Public Service Medal. He has authored over 400 scientific papers with more than 75,000 citations.