Contribution of land use and climate to changes in the global soil carbon mass

Köchy, M. (2011)

I used a Bayesian Network to assess the effects of land use and climate on soil carbon stock. Simulation based on projected changes of climate and land use showed that globally, climate effects on NPP have the strongest impact on soil C. Land use, in contrast, has the greatest effect locally via NPP because the expected global extent of LU changes involving a change in growth form is small. Direct climate effects on decomposition rates were greatest in the humid tropics because of greater absolute increases in decomposition rate with higher temperatures. Regions outside the tropics are most important for the total global soil C mass because of the greater land area. Global soil C mass is expected to increase if NPP increases due to CO2 fertilization. C mass is expected to remain similar or decrease if NPP is limited by N availability. For future assessments of global C stocks I suggest including the effect of high water tables on decomposition rates.