Global soil profiles indicate depth-dependent soil carbon losses under a warmer climate

• Published in: Nature communications Vol. 13; no. 1; pp. 5514 - 11
• Main Authors: Wang, Mingming, Guo, Xiaowei, Zhang, Shuai, Xiao, Liujun, Mishra, Umakant, Yang, Yuanhe, Zhu, Biao, Wang, Guocheng, Mao, Xiali, Qian, Tian, Jiang, Tong, Shi, Zhou, Luo, Zhongkui
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 20-09-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 704/158/47/4113; 704/47/4113; Boreal forests; Carbon; Carbon - analysis; Carbon Sequestration; Climate; Climate Change; ENVIRONMENTAL SCIENCES; Global warming; Humanities and Social Sciences; multidisciplinary; Organic carbon; Organic soils; Science; Science (multidisciplinary); Soil; Soil depth; Soil profiles; Soil properties; Subsoils; Topsoil
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-33278-w

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.
The response of soil organic carbon to climate warming may be soil depth-dependent, but remains unquantified in situ. Here the authors show that warming induces more proportional soil carbon losses in topsoil than in subsoil, particularly from high-latitudinal carbon-rich soils.