Soil carbon is traditionally associated with organic matter. Yet, a landmark study published in Science reveals the global significance of soil inorganic carbon (SIC), a component overlooked mainly due to its prevalence in arid, less fertile regions. Led by Professors Huang Yuanyuan and Zhang Ganlin of the Chinese Academy of Sciences, the research presents compelling evidence that SIC is abundant and important to global carbon dynamics and climate change mitigation.
The study uncovers an astonishing 2,305 billion tons of carbon stored as SIC in the top two meters of soil across the globe—over five times the amount held in the world’s vegetation. This revelation shifts the perspective on global carbon stores, underscoring the potential of SIC to influence climate change strategies. The susceptibility of this carbon pool to environmental changes such as soil acidification, driven by industrial activities and intensive agriculture, poses a significant risk to its stability, calling for immediate attention to soil management practices.
Soil inorganic carbon serves a dual function as a critical carbon store and in maintaining soil health by neutralizing acidity, regulating nutrients, and supporting plant growth. This balance is essential for stabilizing both organic carbon and overall ecosystem services. However, the annual loss of approximately 1.13 billion tons of inorganic carbon to inland waters signifies a pressing need to address this overlooked aspect of carbon cycling.
The findings from this study advocate for a revised approach to climate change mitigation that includes soil inorganic carbon. International efforts, such as the "4 per mille initiative," aim to increase soil organic carbon levels; however, recognizing and incorporating SIC could enhance these strategies, leading to more sustainable soil management and effective climate action. By expanding our understanding of soil carbon dynamics to include both organic and inorganic forms, we can develop more robust strategies to maintain soil health, bolster ecosystem services, and mitigate the adverse effects of climate change.
Professors Huang and Zhang's study challenges existing perceptions to open new pathways for environmental and business sectors to rethink soil management and carbon sequestration strategies in light of these findings. The role of soil inorganic carbon could prove more significant than previously recognized, making it a cornerstone of future environmental strategies.
