Feedbacks between Soil Organic Carbon and Global Warming: Evidence, Mechanisms and Policy Gaps

Abstract

Soil organic carbon (SOC) is central to climate–carbon cycle feedbacks because soils store more carbon than the atmosphere and terrestrial vegetation combined. Rising temperatures, altered precipitation regimes and changing land use are already modifying SOC stocks and fluxes, with potentially strong feedbacks to global warming. This review synthesizes empirical, mechanistic and modelling evidence on how global warming influences SOC dynamics and how SOC changes, in turn, feed back to the climate system. Experimental warming and observational studies reveal substantial but context-dependent SOC losses, particularly from high-latitude and deep soil pools, while some systems show temporary gains or apparent stability. Microbial processes, mineral associations, hydrological changes and disturbance regimes jointly regulate the direction and magnitude of feedbacks. Current Earth system models often underestimate the vulnerability of SOC to warming, partly because of oversimplified microbial dynamics, limited representation of deep and mineral-associated carbon, and incomplete treatment of disturbance and erosion. Emerging approaches, including observationally constrained models and updated global soil respiration databases, are beginning to narrow uncertainties but still diverge in long-term projections. Policymakers increasingly invoke SOC sequestration as a “natural climate solution,” yet recent work questions the scale, permanence and trade-offs of soil-based mitigation. We highlight major policy gaps in integrating SOC feedback into national commitments, monitoring, reporting and verification (MRV) systems, and carbon market rules. Finally, we identify research and governance priorities to ensure that SOC management contributes meaningfully to climate mitigation while safeguarding food security and other ecosystem services.