As an economist, Dr. Töpfer taught at various universities between 1978 and 2007, including in Hannover and Shanghai. Simultaneously, his political career took him into German Federal government. Among other functions, from 1987 to 1994 he was Federal Minister for the Environment, Nature Conservation and Nuclear Safety. After leaving the administration in 1998 he held positions at the United Nations, including the Executive Directorship of the environmental programme. Sustainability and the environment remain constants in his activities.