Siegfried Frederick Singer (born 27 September 1924 in Vienna) is an American atmospheric physicist. Singer is Professor Emeritus of environmental science at the University of Virginia, specializing in planetary science, global warming, ozone depletion, and other global environmental issues. In the 1960s Singer was a leading figure in the early development of earth observation satellites, becoming a Special Advisor on space developments to President Eisenhower and establishing the National Weather Bureau's Satellite Service Center as well as becoming its first Director (1962-64). He has subsequently held a variety of academic and government positions, including Professor of environmental science at the University of Virginia (1971-94). In the 1980s and 1990s Singer became associated in the public eye with a number of controversial issues, notably on global warming, on which he opposes the mainstream scientific opinion on climate change. In 1990 he started the Science & Environmental Policy Project (SEPP) as an independent 501(c) 3 non-profit research institute, where he remains as its President.