title: Johannesburg plus 20: From intergovernmental environmental policy to earth system governance.
authors.affiliation: Department of Global Change and Social Systems, Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, 14412 Potsdam, Germany. biermann@pik-potsdam.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Biermann