Co-ordinated versus uncoordinated European carbon tax solutions analysed with GEM-E3 1 linking the EU-12 countries by P. Capros, P. Georgakopoulos, S. Zografakis (NTUniversity Athens) D. Van Regemorter, S. Proost (CES/KULeuven) Paper presented at the symposium on “Economic Aspects of environmental policy making in a federal system” Leuven, 14-16 June 1995; Paper published (1996) in S. Proost (editor) “Economic Aspects of Environmental Policy”, Kluwer Academic Publishers 1 The GEM-E 3 model was built under the auspices of European Commission (DG-XII, co-ordinator P.Valette) by a consortium involving NTUA (co-ordinator), KUL, Un. Mannheim, CORE, Un. Strathclyde and CEA.