Researchers at Oak Ridge National Laboratory are sharing computational resources and expertise to improve the detail and performance of a scientific application code that is the product of one of the world's largest collaborations of climate researchers. The Community Earth System Model couples components of atmosphere, land, ocean, and ice to reflect their complex interactions. By continuing to improve science representations and numerical methods in simulations, and exploiting modern computer architectures, researchers expect to further improve the CESM's accuracy in predicting climate changes.