* Member of the Commission of Inquiry of the 11th and 12th German Bundestag "Protecting the Earth's Atmosphere" (1987-1995)
* Member of the Advisory Board of the German Government's climate (1988-1996)
* Member of the Expert Group for Global Environmental Aspects (GUA) of the BMBF (2000-2003)
* Member of the Scientific Advisory Board of the Center for Environmental Systems Research, University of Kassel (since 2003)
* Member of the Scientific Advisory Board of the Foundation for the Rights of Future Generations (FRFG) (since 2003)´
* Academician Francis of Assisi Academy for the Protection of the Earth
* Chairman of the Scientific Advisory Board of the Climate Protection Initiative "CO2NTRA" of the company Isover (Since 2004)