Collaboration across the modeling community supports critical experiments and scientific advancement.

U.S. climate modeling centers play a central role in understanding and predicting global change on seasonal to centennial timescales. They are engaged in the Coupled Model Intercomparison Project (CMIP), which produces climate projections underpinning the assessments conducted by the Intergovernmental Panel on Climate Change and the U.S. National Climate Assessment. Models developed by these centers are designed for different purposes, from providing operational forecast information to anticipating longer-term changes and improving scientific understanding of how different elements of the Earth system interact and change. The U.S. Climate Modeling Summit (USCMS), convened annually since 2015, provides a venue for communication, collaboration, and coordination of these modeling activities. The Fourth USCMS, held in April 2018, featured discussions of the newest generation of climate models (CMIP6). An outcome of the meeting was a plan for comparison of model skill in simulating climate variability and an investigation of differences across models. During the summit, a workshop on "Land-Atmosphere Interactions and Extremes," involving discussion of modeling approaches and priorities across centers, allowed researchers to learn from one another’s experiences in this rapidly evolving area of research and model development. The USCMS is convened by the USGCRP Interagency Group for Integrative Modeling, comprising agencies that sponsor U.S. climate modeling activities (including DOE, NOAA, NASA, and NSF) and those that are interested in model output application such as the USDA.