Predictive uncertainties in soil organic carbon decomposition modeling

Soil is the largest terrestrial carbon pool, in which a minor change of carbon fluxes is likely to drastically alter global carbon cycle. Decomposition of soil organic carbon (SOC), releasing CO₂ to the atmosphere, is among the most uncertain components in global carbon budget estimation. To better quantify the turnover rate and stability of soil carbon pools across the planet requires a thorough understanding of current predictive capability. By synthesizing terrestrial biosphere model ensembles from the MsTMIP and field observations, we examined modeled sensitivity of SOC decomposition to major environmental forcings, and quantified possible reasons contributing to wide model spread.