Net carbon losses in Central African forests revealed by high-resolution biomass change maps

Dense humid forests in Central Africa hold vast biomass carbon stocks but face increasing pressure from logging, clearings, and fire disturbances. Many of these disturbance events have a small spatial scale and are missed by current satellite observations. To address this knowledge gap we generated annual 10 meter resolution maps of canopy height from 2019 to 2022 using a deep learning model fusing spaceborne lidar height measurements with Sentinel radar and optical imagery. The maps reveal widespread previously undetected small disturbance patches, with 87% of all the disturbances being of less than 1 ha in size. These disturbance patches smaller than 1 ha account for 48% of the biomass carbon gains in regrowing forests and for 37% of carbon losses from deforestation. We found a net carbon loss of −58 ± 9 Tg C yr⁻¹ composed of a gross loss of −126 ± 7 Tg C yr⁻¹ partially offset by a gain of 68 ± 6 Tg C yr⁻¹, implying a turnover of biomass carbon from disturbances of 0.52% per year. The Democratic Republic of the Congo is a small net source of carbon (−46 ± 6 Tg C yr⁻¹) due to degradation, despite having the largest carbon gains in young secondary forests. Across the Congo Basin, protected areas show a net biomass loss of −4 ± 1 Tg C yr⁻¹, with a gross loss of −14 ± 1 Tg C yr⁻¹, highlighting uneven conservation outcomes. Our remote-sensing data aggregated into national carbon budgets align well with country-level inventories and bookkeeping model estimates, paving the way for spatially explicit and transparent carbon monitoring.