1. John F. Kennedy School of Government, Harvard University, Cambridge, MA, USA.
2. School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA.
3. Robert Day School of Economics and Finance, Claremont McKenna College, Claremont, CA, USA.
4. Department of Agricultural and Resource Economics, University of California, Berkeley, Berkeley, CA, USA.
5. Department of Economics, Georgetown University, Washington, DC, USA.
6. Resources for the Future, Washington, DC, USA.