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Overview
CMIP is continuing to evolve into a more continuous approach with small targeted “fast track” experiment sets, in addition to the DECK and the growing number of Community MIPs. The CMIP fast tracks are designed as a compact set of experiments including the DECK and selected experiments from Community MIPs that will support specific needs. The first fast track, “Assessment Fast Track” will respond to the needs of national and international climate assessment including the IPCC AR7. CMIP infrastructure, standards and tools will continue to support ongoing science and assessment activities. This design reflects extensive feedback from the modelling centres and wider user community.
CMIP7 Research Questions
The CMIP Panel have collated four Fundamental Research Questions motivating Coupled Model intercomparison, which the data from CMIP7 will help to address substantially. Full descriptions of the science questions can be found in the CMIP7 Overview Paper (Dunne et al., 2025), currently being prepared for final submission.
- Patterns of sea surface change: How will tropical ocean temperature patterns co-evolve with those at higher latitudes?
- Changing weather: How will dangerous weather patterns evolve?
- Water-carbon-climate nexus: How will Earth respond to human efforts to manage the carbon cycle?
- Tipping Points: What are the risks of triggering irreversible changes across possible climate trajectories?
The DECK
As in CMIP6, running the Diagnostic, Evaluation and Characterization of Klima (DECK) will remain the “entry card” for CMIP, including the Assessment Fast Track. Community feedback on potential changes to the DECK have been received by the Panel. At their meeting in March 2024, the WGCM endorsed the CMIP Panel recommendation to include the following experiments in the DECK, in addition to amip, abrupt4xCO2, piControl (and esm-piControl for ESMs), and 1pctCO2:
- historical
- esm-hist (for ESMs only)
- piClim-control
- piClim-anthro
- piClim-4xCO2
The CMIP Panel confirmed their decision to ensure emissions-driven experiments are well proven and tested before inclusion as an ESM-DECK, and to consider proposals for inclusion of LMIP and OMIP in the DECK, in the future.
The Community MIPs
- 35 MIPs have registered and can be found on the CMIP website.
- The CMIP Panel will not be endorsing MIPs but have provided best practice guidance.
- Requests for Panel feedback and support from the CMIP IPO can be submitted through the registration form.
- The Panel wants to encourage MIPs to not re-run CMIP6 experiments with new models, and to collaborate across MIPs to identify and reduce any potential duplication, and with consideration of their carbon footprint.
- If MIPs have information/news they would like to share with CMIP community, then email the CMIP IPO.
CMIP7 Assessment Fast Track (CMIP7 AFT)
The CMIP Panel and WGCM Infrastructure Panel (WIP) continue to discuss and evolve the CMIP delivery timeline in close coordination with the CMIP Task Teams and through regular engagement with the wider community. For the DECK and the subset of CMIP experiments aimed at aligning with the IPCC and other national and international climate assessments, the CMIP7 Assessment Fast Track, there can be no definitive timeline until the IPCC approve the Working Group I timeline (expected at the next IPCC Plenary in July 2025). Community MIPs do not need to align with that timeline, although they may choose to do so. Our working timeline is outlined below, this is being reviewed regularly in consultation with the community.
In September 2023 the Strategic Ensemble Design (SED) Task Team provided a first proposed set of Assessment Fast Track experiments after discussions with the Task Team members, stakeholders and MIPs. Two rounds of consultation followed with the modelling centres and with the wider community. After further discussion within the SED TT, CMIP Panel and with proposing MIPs a final recommendation of the Assessment Fast Track experiment selection (figure below) was made to the WGCM meeting in March 2024, and subsequently endorsed.
The CMIP7 AFT experiments
Want to learn more about the experiments and why they were selected for the Assessment Fast Track? The figure below summarises all of the experiments chosen for the Assessment Fast Track, along with which MIP proposed them. The interactive experiment viewer underneath the figure also outlines why each experiment was selected.
Fast Track experiment viewer
If you are having trouble viewing the experiment viewer, you can click here to view in a new tab.
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