As climate change has pushed climate patterns outside of historic norms, the need for detailed projections is growing across all sectors, including agriculture, insurance, and emergency preparedness planning. A National Strategy for Advancing Climate Modeling emphasizes the needs for climate models to evolve substantially in order to deliver climate projections at the scale and level of detail desired by decision makers, this report finds. Despite much recent progress in developing reliable climate models, there are still efficiencies to be gained across the large and diverse U.S. climate modeling community. Evolving to a more unified climate modeling enterprise-in particular by developing a common software infrastructure shared by all climate researchers and holding an annual climate modeling forum-could help speed progress. Throughout this report, several recommendations and guidelines are outlined to accelerate progress in climate modeling. The U.S. supports several climate models, each conceptually similar but with components assembled with slightly different software and data output standards. If all U.S. climate models employed a single software system, it could simplify testing and migration to new computing hardware, and allow scientists to compare and interchange climate model components, such as land surface or ocean models. A National Strategy for Advancing Climate Modeling recommends an annual U.S. climate modeling forum be held to help bring the nation's diverse modeling communities together with the users of climate data. This would provide climate model data users with an opportunity to learn more about the strengths and limitations of models and provide input to modelers on their needs and provide a venue for discussions of priorities for the national modeling enterprise, and bring disparate climate science communities together to design common modeling experiments. In addition, A National Strategy for Advancing Climate Modeling explains that U.S. climate modelers will need to address an expanding breadth of scientific problems while striving to make predictions and projections more accurate. Progress toward this goal can be made through a combination of increasing model resolution, advances in observations, improved model physics, and more complete representations of the Earth system. To address the computing needs of the climate modeling community, the report suggests a two-pronged approach that involves the continued use and upgrading of existing climate-dedicated computing resources at modeling centers, together with research on how to effectively exploit the more complex computer hardware systems expected over the next 10 to 20 years. Table of ContentsFront MatterSummaryPART 1: Background1 Introduction2 Lessons from Previous Reports on Climate ModelingPART 2: Current Issues in Climate Modeling3 Strategies for Developing Climate Models:Model Hierarchy,Resolution, and Complexity4 Scientific Frontiers5 Integrated Climate Observing System and Earth System Analysis6 Characterizing, Quantifying, and Communicating Uncertainty7 Climate Model Development Workforce8 Relationship of U.S. Climate Modeling to Other International andNational Efforts9 Strategy for Operational Climate Modeling and Data DistributionPART 3: Strategy for Advancing Climate Modeling10 Computational Infrastructure - Challenges and Opportunities11 Synergies Between Weather and Climate Modeling12 Interface with User and Educational Communities13 Strategies for Optimizing U.S. Institutional Arrangements14 A National Strategy for Advancing Climate ModelingReferencesAppendixesAppendix A: Statement of TaskAppendix B: Community InputAppendix C: Biographical Sketches of Committee Members