United Nations Under-Secretary-General, Director-General of the United Nations Office at Nairobi, Executive Director of the United Nations Environment Programme (UNEP) and Acting Director of the United Nations Center for Human Settlements (Habitat) holds a Doctorate in Philosophy and a degree in Economics.

Prior to joining the United Nations and from 1994 to 1998, he was Federal Minister for Regional Planning, Building and Urban Development and Co-ordinator of the transfer of the Parliament and Federal Government to Berlin.

From 1987 to 1994, he was Federal Minister for the Environment, Nature Conservation and Nuclear Safety. From 1990 to 1998, he was a member of the German Bundestag and from 1985 to 1987, Minister for Environment and Health of Rhineland-Palatinate in Germany.

From 1978 to 1985, he was State Secretary at the Ministry for Social Affairs, Health and Environment for the same region. From 1983 to 1987, he was Vice-Chairman of the Federal Committee on Environmental Questions of the Christian Democratic Union (CDU).

He was Head of the Economics Department of the Central Institute for Regional Planning in Munster and Full Professor at the University of Hanover, Director of the Institute for Regional Research and Development.

He is the recipient of a number of honours including

• the Order of Merit of the Federal Republic of Germany (1986),
• the Commander's Cross of the Order of Merit of the Federal Republic of Germany (1989),
• and the Grand Cross of the Order of Merit of the Federal Republic of Germany.
• In 1997 and 1998, he was made Honorary Professor of Tongji University, Shanghai, People's Republic of China
• and Honorary Doctor of Brandenburgische Technical University, Cottbus, Germany.