Increasing Turnover Rising concentrations of CO 2 in the atmosphere are likely to stimulate plant growth, leading to increased biomass and soil carbon stocks, thereby lessening the rate of the rise in atmospheric CO 2 levels. Van Groenigen et al. (p. 508 , published online 24 April) report the results of a meta-analysis and modeling that show that increasing the concentration of atmospheric CO 2 also stimulates microbial decomposition of organic carbon in soils, by roughly the same amount that it increases soil organic carbon, leading to lower equilibrium soil carbon inventories and limiting the accumulation of carbon. Thus, soils may not provide as much carbon storage as hoped.

Faster Decomposition Under Increased Atmospheric CO 2 Limits Soil Carbon Storage