Effects of Warming on Change Rate of Soil Organic Carbon Content in Forest Soils

Climate warming affects the carbon cycle in terrestrial environments. However, the effects of warming on the change rate of soil organic carbon (SOC) content in forest soils are unclear. Here, we extracted 276 data points from 98 published papers to examine the effects of warming on the change rate of SOC content in the soil mineral profile (0-20 or 0-30 cm), focusing on the regulatory effects of warming magnitude and duration and the humidity index. Warming promoted an increase in SOC content from 67.47 to 69.90 g kg(-1) in forest soils, with a change rate of SOC content of 0.85 g kg(-1) yr(-1) on a global scale. The change rate of SOC content decreased from 1.22 to 0.11 g kg(-1) yr(-1) at a warming magnitude of 0-2 and >2 degrees C, respectively, and it changed from 0.96 to -0.81 to -0.51 g kg(-1) yr(-1) at warming durations of 0-5, 5-10, and >10 years, respectively. The change rate of SOC content was higher at a humidity index value of 30-50 than at 0-30 and >50. Although climate warming increases the SOC content, the change rate of SOC content decreases with increased magnitude and duration of warming but increases with an increased humidity index. These findings help elucidate SOC accumulation in the context of climate change.