Climate change is one of the most important global environmental problems facing the world today. Policy decisions are already being made to limit or adapt to climate change and its impacts, but there is a need for greater integration between science and decision making. This book proposes six priorities for restructuring the United States' climate change research program to develop a more robust knowledge base and support informed responses: * Reorganize the Program Around Integrated Scientific-Societal Issues * Establish a U.S. Climate Observing System * Support a New Generation of Coupled Earth System Models * Strengthen Research on Adaptation, Mitigation, and Vulnerability * Initiate a National Assessment of the Risks and Costs of Climate Change Impacts and Options to Respond * Coordinate Federal Efforts to Provide Climate Information, Tools, and Forecasts Routinely to Decision Makers