Matthew E. Kahn is a Professor at the UCLA Institute of the Environment, the UCLA Department of Economics and the UCLA Department of Public Policy. He is now a Visiting Professor at the Department of Economics, USC. He is a research associate at the National Bureau of Economic Research. Before joining the UCLA faculty in January 2007, he taught at Columbia and the Fletcher School at Tufts University. He has served as a Visiting Professor at Harvard and Stanford. He holds a Ph.D. in Economics from the University of Chicago. He is the author of Green Cities: Urban Growth and the Environment (Brookings Institution Press 2006) and the co-author of Heroes and Cowards: The Social Face of War (Princeton University Press 2009). He blogs on environmental and urban topics at greeneconomics.blogspot.com.