1 Tyndall Centre, University of Manchester, Manchester M13 9PL, UK. Centre for Sustainable Development, Uppsala University, 75236 Uppsala, Sweden. kevin.anderson@manchester.ac.uk glen.peters@cicero.oslo.no.
2 Center for International Climate and Environmental Research-Oslo (CICERO), Pb. 1129 Blindern, 0318 Oslo, Norway. kevin.anderson@manchester.ac.uk glen.peters@cicero.oslo.no.