WCRP Coupled Model Intercomparison Project (Phase 6)

The Coupled Model Intercomparison Project, which began in 1995 under the auspices of the World Climate Research Programme (WCRP), is now in its sixth phase (CMIP6). CMIP6 coordinates somewhat independent model intercomparison activities and their experiments which have adopted a common infrastructure for collecting, organizing, and distributing output from models performing common sets of experiments. The simulation data produced by models under previous phases of CMIP have been used in thousands of research papers (some of which are listed here), and the multi-model results provide some perspective on errors and uncertainty in model simulations. This information has proved invaluable in preparing high profile reports assessing our understanding of climate and climate change (e.g., the IPCC Assessment Reports).

The following links will lead to additional information about CMIP6:

• The guidance for users document (and links therein) should be consulted before downloading data.
• The WGCM website and PCMDI-hosted pages provide background information.
• Eyring et al. (2016) have published a CMIP6 overview paper in a Geoscientific Model Development Special Issue, which also includes descriptions of each of the CMIP6-Endorsed MIPs. An overview of the design of the infrastructure supporting preparation and distribution of model output is provided by Balaji et al. (2018).
• The Terms of Use must be followed by all who access CMIP6 model output, so please read them carefully.
• Please register on the CMIP6 publication database any articles you publish that make use of CMIP6 output.

The complete archive of CMIP6 output is made available for search and download via each of the following portals:

• USA, PCMDI/LLNL (California) - https://esgf-node.llnl.gov/search/cmip6/
• France, IPSL - https://esgf-node.ipsl.upmc.fr/search/cmip6-ipsl/
• Germany, DKRZ - https://esgf-data.dkrz.de/search/cmip6-dkrz/
• UK, CEDA - https://esgf-ui.ceda.ac.uk/cog/search/cmip6-ceda/

If you encounter slow responses from one portal, you might try one of the alternatives (perhaps one near you). Also note that the datasets themselves are stored (and partially replicated) on a federated system of data nodes, and again the user may find differences from node to node in download speeds.