1. D. G. Streets is in the Decision and Information Sciences Division, Argonne National Laboratory, Argonne, IL 60439, USA.
2. K. Jiang and X. Hu are at the Center for Energy, Environment and Climate Change, Energy Research Institute, Beijing 100038, China.
3. J. E. Sinton is in the Energy Analysis Department, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
4. X.-Q. Zhang and D. Xu are at the Forest Ecology and Environment Institute, Chinese Academy of Forestry, Beijing 100091, China.
5. M. Z. Jacobson is in the Department of Civil and Environmental Engineering, Stanford University, CA 94305, USA.
6. J. E. Hansen is at the NASA Goddard Institute for Space Studies, New York, NY 10025, USA.