Global patterns of stabilized soil organic carbon and their potential implications for climate mitigation

Stabilized soil organic carbon is the most persistent fraction of soil carbon and plays a key role in long-term climate mitigation, yet its global distribution remains poorly constrained. Here we integrate georeferenced soil profiles with a machine learning model to map stabilized soil carbon in the upper one meter of soils worldwide. Global stabilized soil carbon is estimated at 1304 petagrams of carbon, representing about half of total soil carbon and concentrated in wetlands and cold-temperate regions. Soil properties explain most of the spatial variation, whereas climate and management effects show threshold responses. We further define soil negative carbon potential, the proportion of stabilized carbon in total soil carbon, as an indicator of stabilization efficiency and mitigation potential. Increasing this metric is associated with lower greenhouse gas emissions and improved economic outcomes with minimal yield trade-offs. These results provide benchmarks for Earth system models and inform soil-based climate mitigation strategies. Stabilized soil organic carbon totals 1304 pentagrams carbon globally about half of total soil carbon concentrated in wetlands and cold regions shown by mapping upper one-meter soils using georeferenced soil profiles and high precision machine learning models.