Numerical models are fundamental tools in climate research. They range from very detailed models of a particular process, through complex global and regional climate or earth system models, to more idealized climate system models. They are used in a wide variety of applications including studies of processes, data assimilation and analysis, attribution, historical and paleo­climate simulation, seasonal to interannual climate prediction, future climate projections, and regional downscaling. Additionally, climate services and related information used for societal and policy purposes are largely based on the output of such models.

Modelling is a core activity for WCRP, and every WCRP project has a set of modelling activities. The WCRP Modelling Advisory Council (WMAC) coordinates high-level aspects of modelling across WCRP, ensuring cooperation with key partners, such as World Weather Research Programme (WWRP), and acting as a single entry point for all WCRP modeling activities.

WMAC works with the WCRP Data Advisory Council (WDAC) to promote the effective use of models with observations, and address aspects of modelling in data assimilation, reanalysis, Observing System Sensitivity Experiments and in paleoclimatic research.

The three modelling and prediction groups below oversee the development of various types of modelling.

Regional downscaling activities are currently overseen by the Coordinated Regional Climate Downscaling Experiment (CORDEX).

The Subseasonal-to-Seasonal Prediction Project (S2S), conducted jointly by WCRP and WWRP, builds on synergies between the weather and climate communities.