Jeroen C.J.M. van den Bergh, ICREA Professor, Autonomous University of Barcelona, Spain and Professor of Environmental and Resource Economics, Free University, Amsterdam, Albert Faber, formerly Scientific Council for Government Policy (WRR), The Hague, Annemarth M. Idenburg, Trendbureau Overijssel and Frans H. Oosterhuis, Institute for Environmental Studies, VU University, Amsterdam, the Netherlands