Coverage of novel CDR and CCUS in GHG inventories – needs for IPCC guidance

Novel methods for carbon dioxide removal (CDR) and carbon capture and use or storage (CCUS) are widely being explored to achieve greenhouse gas (GHG) neutrality. These novel approaches are linked to activities that are not yet sufficiently covered in available guidance for GHG inventories. This working paper summarises a list of subjects to be possibly addressed in the IPCC Methodology report on Carbon Dioxide Removal Technologies, Carbon Capture Utilisation and Storage to be elaborated by 2027. The subjects covered in this working paper comprises reporting approaches and definitions (removal definitions and upstream vs. downstream CCU reporting approaches), quantification methodologies for emissions (emission factors for synthetic fuels, biomass definition with respect to CCU, capture of biogenic CO₂ in the agriculture and waste sectors, reporting biogenic CO₂ in energy and IPPU sectors, fugitive CO₂ emissions from international CO₂ transport, and carbon capture during international navigation), quantification methodologies for removals from the atmosphere (direct air capture, enhanced rock weathering, ocean alkalinisation and concrete carbonation) and quantification methodologies related to biogenic carbon pools (non-wood biomass storage products, biomass dumping and biochar applications beyond soils). The paper has been drafted as an input for further consideration to the IPCC Workshop on Carbon Dioxide Removal Technologies and Carbon Capture Utilisation and Storage to be held in Vienna, Austria 1-3 July 2024.