Climate Adaptation Science Centers Act or the CASC Act This bill provides statutory authority for the National and Regional Climate Adaptation Science Centers of the U.S. Geological Survey (USGS). The centers must provide scientific expertise to managers of natural resources, cultural resources, and ecosystem services to inform decisions that aid adaptation to a changing climate and extreme weather events. The program shall include a National Climate Adaptation Science Center and Regional Climate Adaptation Science Centers. Among its activities, the National Center shall serve as the national office for the regional centers, develop and facilitate coordination among the regional centers, and conduct research on cross-regional and national science priorities. Regional centers shall develop research, education, training, and advisory service priorities regarding the impacts of climate trends and variability on natural and cultural resource management. The USGS shall establish an Advisory Committee on Climate and Natural Resource Sciences to identify and recommend priorities for ongoing research needs on such impacts in informing the research priorities of the National Center.