Abstract
As part of the REgional Carbon Cycle Assessment and Processes Phase 2
(RECCAP2) project, we developed a comprehensive African Greenhouse gases
(GHG) budget for the period 2010-2019 and compared it to the budget over
the 1985-2009 (RECCAP1) period. We considered bottom-up process-based
models, data-driven remotely sensed products, and national GHG
inventories in comparison with top-down atmospheric inversions,
accounting also for lateral fluxes. We incorporated emission estimates
derived from novel methodologies for termites, herbivores, and fire,
which are particularly important in Africa. We further constrained
global woody biomass change products with high-quality regional
observations. During the RECCAP2 period, Africa’s carbon sink capacity
is decreasing, with net ecosystem exchange switching from a small sink
of −0.61 ± 0.58 PgCyr−1 in RECCAP1 to a small source in RECCAP2 at 0.162
(-1.793/2.633) PgCyr-1. Net CO2 emissions estimated from bottom-up
approaches were 1.588 (-6.461/11.439) PgCO2yr-1, net CH4 were 78.453
(36.665/59.677) TgCH4yr-1) and net N2O were 1.81 (1.716/2.239)
TgN2Oyr-1. Top-down atmospheric inversions showed similar trends. LUC
emissions increased, representing one of the largest contributions at
1.746 (0.841/2.651) PgCO2eq yr-1 to the African GHG budget and almost
similar to emissions from fossil fuels at 1.743 (1.531/1.956) PgCO2eq
yr-1, which also increased from RECCAP1. Additionally, wildfire
emissions decreased, while fuelwood burning increased. For most
component fluxes, uncertainty is large, highlighting the need for
increased efforts to address Africa-specific data gaps. However, for
RECCAP2, we improved our overall understanding of many of the important
components of the African GHG budget that will assist to inform climate
policy and action.