Jointly sponsored with WCRP-SPARC, AC&C sought to improve the representation of chemistry/climate interactions in models. Activities within AC&C were coordinated with modeling activities such as SPARC’s Chemistry-Climate Model Validation Activity (CCMVal), the Aerosol Comparisons between Observations and Models (AeroCom) project, and the Task Force on Hemispheric Transport of Air Pollution (HTAP) to assure maximum efficiency in model runs, meeting planning, and resources. AC&C consisted of four efforts: Bounding the Role of Black Carbon in Climate, the Model Intercomparison Project (ACCMIP), Hindcast, and Vertical Distributions.