Short bio: Austrian citizen. PhD with Vienna University of Technology in 1988. 2003 habilitation (full permit of university teaching) in environmental chemistry. Since 2003 with the International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria, now as a Senior Research Scholar. From 2012 to 2014, this position was held concurrently with that of a Professor of Systems Sciences at the University of Graz. Research interests: atmospheric processes and global/regional elemental cycles, specifically nitrogen cycles, and their interactions with human and social systems.