Climate Adaptation Science Centers Act or the CASC Act This bill provides statutory authority for the Department of the Interior's National and Regional Climate Adaptation Science Centers. 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. Interior shall establish an Advisory Committee on Climate and Natural Resource Sciences to advise the National and Regional Climate Adaptation Science Centers on specified matters, including (1) the contents of a national strategy identifying key climate adaptation science priorities to advance the management of natural and cultural resources in the face of climate change; and (2) the integration of equity, particularly for historically underserved communities, in the operation of the National Center and regional centers.