Richard Siegmund Lindzen (born February 8, 1940) is an American atmospheric physicist known for his work in the dynamics of the middle atmosphere, atmospheric tides, and ozone photochemistry. He has published more than 200 scientific papers and books. From 1983 until his retirement in 2013, he was Alfred P. Sloan Professor of Meteorology at the Massachusetts Institute of Technology. He was a lead author of Chapter 7, "Physical Climate Processes and Feedbacks," of the Intergovernmental Panel on Climate Change?s Third Assessment Report on climate change. He has criticized the scientific consensus about climate change and what he has called "climate alarmism."