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2025-10-29 update#

CMIP7 DECK historical forcings#

The full set of CMIP7 DECK historical forcings are now available and can be accessed here and below:

  1. Anthropogenic short-lived climate forcer (SLCF) and CO2 emissions
  2. Open biomass burning emissions
  3. Land use
  4. Greenhouse gas concentrations
  5. CO2 isotopes
  6. Stratospheric volcanic SO2 emissions and aerosol optical properties
  7. Ozone concentrations
  8. Nitrogen deposition
  9. Solar
  10. AMIP sea-surface temperature and sea-ice boundary forcing
  11. Aerosol optical properties/MACv2-SP
  12. Population density

Please continue to ask questions and engage in discussions at the input4MIPs Github discussions and find all information relevant to CMIP7 Forcing datasets at https://wcrp-cmip.org/cmip-phases/cmip7/cmip7-forcing-datasets/

CMIP7 scenarios update and forcings development#

Scenarios update Responding to comments received during open community review of van Vuuren et al (2025) the ScenarioMIP Scientific Steering Committee and Advisory Group have updated some of the CMIP7 scenario names. Very Low Low Overshoot (VLLO) becomes Very Low (VL) and Very Low High Overshoot (VLHO) becomes Low to Negative (LN). A High-Low (HL) scenario that follows the high scenario until rapid mitigation begins around 2050 has also been added. An updated version of van Vuuren et al (2025) is expected to be available very soon.

CMIP7 Scenario forcing development A number of preliminary scenario forcing datasets have already been made available via ESGF (see here for more information and links to the data) and are ready for testing by any interested modelling centres or data analysts. We encourage users to test the available datasets and provide feedback via input4MIPs Github discussions as soon as possible to refine the final scenario forcing development.

A small number of the scenario forcings (land use, ozone and nitrogen deposition) cannot produce all seven scenarios at the same time. Therefore, a scenario running order has been developed in close collaboration with ScenarioMIP and downstream activities such as ISIMIP, ISMIP7 and CORDEX, who require scenario data by July 2026 to facilitate their contribution to AR7. As outlined in Dunne et al. (2025) the CMIP Panel strongly encourages modelling centres to follow a running order, first running the H and VL scenario simulations, for which scenario forcings will be delivered by January 2026. Within the survey, accompanying this update, we are requesting feedback to support further guidance on the running order of the remaining scenarios up to 2100 and extensions out to 2300/2500.

Scenario Scenario extension Based on SSP
High (H)* H-ext SSP3
Very Low (VL)* VL-ext SSP1
High Low (HL) HL-ext SSP5
Medium (M) M-ext SSP2
Medium Low (ML) ML-ext SSP2
Low (L) L-ext SSP2
Low to Negative (LN) LN-ext SSP2

Note: H and VL will be made available first to allow the chemistry-climate models to be initiated.