Terrance Arthur Tamminen (born March 7, 1952) is an author, lecturer, and strategist on energy and the environment. In 2003, California Governor Arnold Schwarzenegger appointed him as Secretary of the California Environmental Protection Agency. In December 2004, he was appointed Cabinet Secretary, the Chief Policy Advisor to the Governor. He continues to advise the former governor, and other regional, national, and international leaders, on energy and environmental policy.
Tamminen was born in Milwaukee, Wisconsin, but spent most of his youth in Australia. In the 1960s he helped run a family-run tropical fish breeding business in Australia. He continued to focus on oceans with studies on conch depletion in the Bahamas, manatee populations in Florida coastal waters, and mariculture in the Gulf States with Texas A&M University.
Tamminen is a United States Coast Guard-licensed ship captain. He is also an avid airplane and helicopter pilot and speaks German, Dutch and Spanish.
In 1993, Tamminen founded the Santa Monica Baykeeper and served as its Executive Director for six years. He co-founded Waterkeeper programs in San Diego, Orange County, Ventura, and Santa Barbara. He also served for five years as Executive Director of the Environment Now Foundation in Santa Monica, CA and co-founded the Frank G. Wells Environmental Law Clinic at the School of Law, University of California Los Angeles. In April, 2007, he was named the Cullman Senior Fellow and Director of the Climate Policy Program of The New America Foundation, a non-profit, post-partisan, public policy institute. In February 2007, Tamminen founded the non-profit Seventh Generation Advisors, where he currently serves as Executive Director. In 2011, Terry helped former Governor Arnold Schwarzenegger found the R20 Regions of Climate Action and was appointed as the Strategic Advisor to the Founding Chair. As the Founding Chair’s Strategic Advisor, he advises the R20 on policy and helps with the design and implementation of climate resilient economic development projects. In 2016, Terry was named CEO of the Leonardo DiCaprio Foundation, where he will oversee operations, the implementation of a new comprehensive climate change action plan, and numerous global environmental and climate change initiatives.