Deep cuts in the global warming emissions will require international cooperation. The field of international relations, a branch of political science, can help explain when cooperation will be effective and why so many past efforts at coordination, such as the Kyoto Protocol, have been designed to look impressive yet have little real impact.

Robert O. Keohane is Professor of International Affairs, Princeton University. He is the author of After Hegemony: Cooperation and Discord in the World Political Economy (1984) and Power and Governance in a Partially Globalized World (2002). He has served as the editor of the journal International Organization and as president of the International Studies Association and the American Political Science Association. He won the Grawemeyer Award for Ideas Improving World Order, 1989, and the Johan Skytte Prize in Political Science, 2005.