In 1985, he was appointed Minister of Environment and Health of the State of Rhineland-Palatinate, and in 1987 Federal Minister for the Environment, Nature Conservation and Nuclear Safety. He held this post until 1994, when he took the office of Federal Minister for Regional Planning, Housing and Urban Development. In 1998, he left Germany to become Executive Director of the United Nations Environment Programme (UNEP) in Nairobi and Under-Secretary-General of the United Nations. After two terms in office, he chose to return to academia in 2007 as Professor of Environment and Sustainable Development at Tongji University in Shanghai, as well as Visiting Professor at the University of Koblenz-Landau. In 2009 he was appointed founding director of the Potsdam-based Institute for Advanced Sustainability Studies (IASS) and continues to serve as the institute’s executive director.
Among Professor Töpfer’s many honours is the German Sustainability Award for his lifetime achievement in the field of sustainability. He serves on the advisory boards of the German Foundation for World Population and of the Holcim Foundation for Sustainable Construction. He has been a member of the German Council for Sustainable Development (RNE) since 2001 and is currently co-chairman of the Federal Government’s Ethics Commission on a Safe Energy Supply.