Aim and Objectives
The Coupled Climate–Carbon Cycle Model Intercomparison Project (C4MIP) takes responsibility for the coordinated design, documentation, and analysis of carbon-cycle feedbacks and interactions in climate simulations. Carbon-cycle feedbacks are potentially large and play a leading-order contribution in determining the atmospheric composition in response to human emissions of CO2 and in the setting of emissions targets to stabilize climate or avoid dangerous climate change. The C4MIP community contributes to the experimental design, but the simulations fit within the wider Climate Model Intercomparison Project activities (CMIP, currently CMIP7) that enable systematic and robust analysis of results across many models. C4MIP is also closely related to the WCRP light house activity Safe Landing Climates.
C4MIP evolves, but retains three key strands of scientific motivation:
- pre-industrial and historical simulations (formally part of the common set of DECK experiments) to enable model evaluation
- idealized coupled and partially coupled simulations with 1% per year increases in CO2 to enable diagnosis of feedback strength and its components, quantify TCRE and ZEC and understand processes surrounding reversibility and symmetry to negative emissions
- future scenario simulations to project how the Earth system will respond to anthropogenic activity over the 21st century and beyond. Focus moving towards low (policy relevant) pathways with and without overshoot will be invited to contribute to central C4MIP analysis papers. We anticipate, and hope, that many further studies and analyses will also be conducted throughout the climate/carbon cycle research community and that these simulations provide a valuable resource to further carbon cycle research.
News:
- 5.2.2026: C4MIP will be presented as part of the virtual showcase events in the lead up to the CMIP Community Workshop 2026, Kyoto in March 2026