The potential carbon benefit in drylands of China

China’s drylands cover a large area and provide important ecosystem services as carbon sink by storing large amounts through vegetation and soils, so that it can be the key component of China’s terrestrial ecosystems. Due to water limitation and severe carbon-water trade-offs, China’s drylands are highly dynamic, which has an important impact on the trend of carbon sequestration in ecosystems of China and the interannual variability. Many studies have focused on carbon storage in cropland, grassland and forest ecosystems, but few comprehensive analyses focused on carbon storage and potentials in China's drylands. Here, we train a model with multiple influence factors to simulate the carbon storage potential in drylands of China to predict the biomass carbon carrying capacity of China’s drylands. After comparing observed and predicted biomass carbon density of drylands of China, we find that the carbon storage in China’s drylands realised by nearly 70 percent. The carbon actual storage in the drylands of the east of Inner Mongolia, the Northeast China, the northern part of Xinjiang, and the Huang-huai-hai region are the highest, and the potential carbon benefits of these places are highest too. Following by the Qinghai-Tibet Plateau and Jin-Shaan-Gan areas, and the lowest carbon storage and potential carbon benefits were found in the central and western parts of Inner Mongolia. Divided by the aridity gradient, it was found that the semi-arid zone has highest potential for carbon storage. We also identified areas where vegetation has not yet reached its full potential, such as the eastern and southern parts of the Tibetan Plateau and the Xinjiang region. Although the potential carbon storage in these areas is low, the proportion of carbon storage realised is below 40 percent, which has higher potential and conservation priority, indicating that the conservation of carbon in drylands of China needs to pay attention to the proportion of carbon sequestration realised at the same time, in addition to the potential carbon benefits.