[A-CG37] Global Carbon Cycle Observation and Analysis

[ACG37-01] Bottom-up evaluation of greenhouse gas budget

*Akihiko Ito^1,2 (1.National Institute for Environmental Studies, 2.Japan Agency for Marine-Earth Science and Technology)

Keywords:Climate change, Emission inventory, Biogeochemical model, Global stocktake

Reliable greenhouse gas budgets at broad scales need to be verified by multiple scientific evidence. In this regard, a bottom-up approach is necessary to compensate the alternative, top-down, approach deriving the budget from atmospheric observational data and models. The bottom-up approach uses mainly emission inventories, biogeochemical models, and land surface data and evaluates individual sources and sinks. This approach has advantages in estimating the budget in a spatially explicit manner and for a long term and in decomposing sectoral contributions. Also, this approach usually does not need expensive instruments. On the other hand, this approach has disadvantages in quick reporting and is susceptible to sector-specific errors and biases. In this presentation, I demonstrate the approach for several regions. First, the CH4 budget of Asia and northern high-latitude regions was analyzed mainly using EDGAR emission inventory and VISIT biogeochemical model. Second, the global CO2, CH4, and N2O budgets was investigated also using the emission inventory and biogeochemical models. Finally, I discuss how the approach can be effective for policy-relevant issues such as the Global Stocktake of the Paris Agreement.