Joseph J. Romm (born June 27, 1960) is an American physicist, author, editor, blogger, and leading climate expert. He earned a Ph.D. in physics from MIT, specializing in physical oceanography. During the Clinton administration, he served for five years at the U.S. Department of Energy, including as Acting Assistant Secretary, managing programs on renewable energy, energy efficiency, and climate policy. After government service, he became a senior fellow at the Center for American Progress, where he founded and edited the influential blog Climate Progress. His work has earned him recognition including Time magazine's 'Hero of the Environment' (2009) and a spot on Rolling Stone's '100 People Who Are Changing America' (2009). He is a Fellow of the American Association for the Advancement of Science and has authored books on energy and climate issues. Romm is known for his advocacy in reducing greenhouse gas emissions, promoting energy efficiency and green technologies, and for his vocal criticism of climate denial efforts. He has also been a fellow at the University of Pennsylvania's Annenberg School for Communication's Center for Science, Sustainability, and the Media, contributing to climate communication and policy discourse. His career spans energy consulting, policy work, and progressive climate activism, with his office associated with the Center for Energy and Climate Solutions in Arlington, Virginia.