The Biomass Carbon Sequestration Potential in China's Drylands

Abstract

Drylands are important carbon pools for climate change mitigation but remain highly vulnerable to climate and anthropogenic pressures. Despite China hosting one of the largest dryland areas globally, limited studies have quantified its biomass carbon storage and sequestration potential. Here, we divided China's drylands into ecological types and climate zones and employed random forest models to estimate biomass carbon carrying capacity and carbon sequestration potential. The results showed that the carrying capacity of China's drylands is 7.1 Pg C, with ∼4.1 Pg C (∼58%) already stored and an additional 3 Pg C potentially sequesterable. Regions with the highest carbon sequestration potential are concentrated in the eastern part of Inner Mongolia, the Northeast China, the northern part of Xinjiang, and the Huang-huai-hai region. Forests showed the highest total carbon carrying capacity (4.2 Pg C) and carbon sequestration potential (2.1 Pg C), followed by grasslands with a carbon carrying capacity of 2.7 Pg C and sequestration potential of 1.6 Pg C. Carbon sequestration thresholds varied across land use change types and aridity gradients. The identified hotspots in our study where vegetation has not yet reached its full potential should be the main target of future restoration projects. It should be noted that these estimates are based on historical climate conditions and land cover patterns, and may vary under future climate change and land use transitions. Therefore, these figures should be interpreted as conditional estimates, reflecting the limitations of using static climatic baselines.