Forest Carbon Diligence: Digital MRV for mapping forest structure and carbon stocks

Carbon markets finance natural climate solutions to accelerate carbon sequestration and reduce carbon emissions. Monitoring, reporting, and verification (MRV) systems are now emerging to provide transparency to voluntary and jurisdictional carbon markets. In forests, MRV systems must estimate patterns of forest structure, tree growth, tree loss, and the corresponding carbon removals or emissions over time. Estimating forest biomass at scale is now possible with spaceborne LiDAR data, which can be fused with other satellite data to map wall-to-wall change over long periods of time. This manuscript describes a novel digital MRV system — Forest Carbon Diligence — which fuses multimodal satellite measurements. This system provides annual maps of canopy cover, canopy height, aboveground carbon density, change detection, and their uncertainties. Validation and intercomparison with open data were used to evaluate performance, providing a replicable approach for describing global forest carbon products. Globally, forest structure regression metrics were high (canopy height r 2 = 0 . 83 , canopy cover r 2 = 0 . 79 ), as were carbon metrics (biomass r 2 = 0 . 64 at 30 m , r 2 = 0 . 82 at 1 km ). The intercomparison analysis found strong agreement with 8 independent datasets in tropical, temperate, and boreal systems. Rigorous digital MRV systems can support policy and market needs by providing scientific, well-calibrated, and consistent estimates of aboveground forest carbon stocks, increasing trust in carbon markets.