In preparation for the 7th Assessment Report of the IPCC, climate modellers are preparing global climate simulations that will be coordinated by the Coupled Model Intercomparison Project (CMIP). Most of these simulations require inputs that describe solar radiative forcing as well as the precipitation of energetic particles in the upper atmosphere.

The CMIP7 working group aims to coordinate the preparation of these forcing datasets, which will consist of a historical reconstruction from 1850 to the present, and scenarios from the present up to 2300. Several of the team members were already involved in the preparation of forcing datasets for CMIP6.

This group will review existing datasets, find the best way to combine them, design future scenarios, agree on the methodology for prescribing ozone variability in a self-consistent way in climate models without interactive chemistry, and prepare meetings to gather community feedback on these issues.

Latest news : Our white paper with a roadmap for making a forcing dataset has now been published, see https://gmd.copernicus.org/articles/17/1217/2024/gmd-17-1217-2024-discussion.html

Main milestones

  • 27-31 March 2023 : A first meeting took place at ISSI, during which decisions were taken regarding the forcing data sets that should be used. The outcomes of that first meeting are summarised in the white paper above.
  • May 2024 : A preliminary version of the data sets will be produced and then tested before being sent to modelling teams so that they can run their models on them.
  • 22-26 July 2024 : Second and final team meeting, with a focus on the making of future scenarios, estimating uncertainties, and ozone specification.