The Community Earth System Model is a fully-coupled global climate model developed in collaboration with colleagues in the research community. CESM provides state-of-the-art computer simulations of Earth's past, present, and future climate states.

NCAR's first community climate model, a global model of the atmosphere, was released in 1983 and made freely available to the research community. Land surface, ocean, and sea ice models were incorporated in the mid-1990s, and working groups formed soon after to address additional components of the Earth system. This partnership with scientists in academia and at other research labs has assured steady improvement and expansion of capabilities in the decades since.