He has repeatedly called attention to the nation's excessive dependence on fossil fuels and the huge economic and environmental costs, and risks.

He has outlined strategies for a clean, renewable energy economy in his books and articles which have appeared in publications such as Huffington Post, Scientific American, The Boston Globe, The Christian Science Monitor, The Los Angeles Times, Huffington Post, and Renewable Energy World.

[citation needed] In 1976, after publishing his first book, Nuclear Power: The Unviable Option, with an introduction by Nobel Laureate Linus Pauling and a foreword by Senator Mike Gravel, he was invited by David Brower to become Friends of the Earth's Energy Projects Director in San Francisco.

[1] The group convened the 1988 Restoring the Earth Conference, which at the time was the most comprehensive meeting ever held on the repair of environmental damage and the re-creation of disrupted ecosystems.

More than 150 scientific papers and popular talks were presented on topics ranging from the restoration of forests, rivers, lakes, streams, wetlands, estuaries, prairies, and mined lands to wildlife and its habitats; as well as prevention, management and containment of toxic wastes.

[2] In addition to his teaching and leadership of environmental organizations, Berger has been a journalist specializing in energy, environment, climate, and natural resources, and he is currently (2023) the U.S.