We provide a brief overview of the proposed structure of CMIP6 to encourage discussion and feedback that will be considered in refining the design.  As an initiative of the World Climate Research Programme (WCRP), the Climate Model Intercomparison Project (CMIP) is meant to provide open access to baseline information about model behavior and performance and focus on three broad science questions: How does the Earth system respond to forcing? What are the origins and consequences of systematic model biases? How can we assess future climate changes given climate variability, climate predictability, and uncertainties in scenarios?

In a change from previous phases of CMIP, CMIP6 will rely on some benchmark experiments, referred to as ongoing Diagnosis, Evaluation, and Characterization of Klima (DECK) experiments (see inner ring of figure), which are already typically revisited by modeling groups each time a new model version is developed.  CMIP6 will also include a subset of the experiments selected from model intercomparisons projects (MIPs) that have been endorsed by the CMIP panel (see outer ring of figure).  All MIPs would adopt similar practices in providing access to output from these experiments (through the Earth System Grid Federation), which potentially reduces resource requirements for participation in multiple MIPs.