The Grand Challenge on Carbon Feedbacks in the Climate System will pursue the following objectives:
I. Process understanding on land:
- quantification of the strength of the CO2 fertilization, photosynthesis and limitations from nitrogen cycle
- quantification of gross carbon fluxes sensitivity to warming and variability (and changes in hydrology)
- understanding of ecosystems vulnerability and risk of carbon loss
II. Process understanding in the ocean:
- quantification of the strength of the Southern Ocean CO2 uptake
- the relative role of physical vs. biological processes in determining ocean carbon sink
- understanding the origins of variability (from seasonal to decadal) of the ocean carbon sink
- relationship between anthropogenic carbon and heat uptake
III. Learning from the existing record:
- observational frameworks
- model evaluation/benchmarking
- developing new emerging constraints
- from paleorecord to satellite data
IV. Towards improved projections:
- improved feedback framework (water cycle, regional focus)
- improved Earth System models
- ESM re-analysis (physics and biogeochemistry)