Global soil profiles indicate depth-dependent soil carbon losses under a warmer climate
Mingming Wang, Xiaowei Guo, Shuai Zhang, Liujun Xiao, Umakant Mishra, Yuanhe Yang, Biao Zhu, Guocheng Wang, Xiali Mao, Tian Wei Qian, Tong Jiang, Zhou Shi, Zhongkui Luo
Abstract
Soil organic carbon (SOC) changes under future climate warming are difficult to quantify in situ. Here we apply an innovative approach combining space-for-time substitution with meta-analysis to SOC measurements in 113,013 soil profiles across the globe to estimate the effect of future climate warming on steady-state SOC stocks. We find that SOC stock will reduce by 6.0 ± 1.6% (mean±95% confidence interval), 4.8 ± 2.3% and 1.3 ± 4.0% at 0-0.3, 0.3-1 and 1-2 m soil depths, respectively, under 1 °C air warming, with additional 4.2%, 2.2% and 1.4% losses per every additional 1 °C warming, respectively. The largest proportional SOC losses occur in boreal forests. Existing SOC level is the predominant determinant of the spatial variability of SOC changes with higher percentage losses in SOC-rich soils. Our work demonstrates that warming induces more proportional SOC losses in topsoil than in subsoil, particularly from high-latitudinal SOC-rich systems.