1. Center for Social and Environmental Systems Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506 Japan
2. Department of Environmental Engineering, Kyoto University, 361 Kyoto University Katsura Campus, Nishikyo-ku, Kyoto, 6158540, Japan
3. International Institute for Applied Systems Analysis, Schlossplatz-1, 2361 Laxenburg, Austria