Scott Barrett is the first Lenfest-Earth Institute Professor of Natural Resource Economics at Columbia University. He researches the policy response to transnational challenges, including global climate change and the control of infectious diseases, and he has been an advisor to many organizations, including the European Commission, the International Task Force on Global Public Goods, the OECD, the World Bank, and the United Nations. His most recent book, “Why Cooperate? The Incentive to Supply Global Public Goods,” was published by Oxford University Press in September 2007. Dr. Barrett was also lead author of an earlier assessment report by the Intergovernmental Panel on Climate Change.