The legacy of one hundred years of climate change for organic carbon stocks in global agricultural topsoils

Abstract

Abstract Soil organic carbon (SOC) of agricultural soils is observed to decline in many parts of the world. For tearing apart management and climate change effects, the latter needs to be estimated comprehensively. In this study, an established FAO framework was used to model global agricultural topsoil SOC stock dynamics from 1919 to 2018 as attributable to climate change. On average, global agricultural topsoils lost 2.5±2.3 Mg C ha-1 with constant net primary production (NPP) or 1.6±3.4 Mg C ha-1 when NPP was modified by temperature and precipitation. Regional variability could be explained by the complex patterns of changes in temperature and moisture, as well as initial SOC stocks. However, average SOC losses have been an intrinsic and persistent feature of climate change in all climatic zones. This needs to be taken into consideration in reporting or accounting frameworks and halted in order to mitigate climate change and secure soil health.