Identification of natural and anthropogenic sources and the effects of climatic fluctuations and land use changes on dust emissions variations in the Qinghai-Tibetan Plateau

Abstract

Human activity in modulating dust emissions is one of the major causes of large uncertainties in the global dust budget. However, the division of natural and anthropogenic dust sources remains controversial, and the natural and anthropogenic effects on the variations in dust emissions were hardly distinguished. To bridge these gaps, a model was employed to simulate the dust emission processes over the Qinghai-Tibetan Plateau (QTP) whose dust yield remains uncertain. Integrating the Human Activity Intensity (HAI) dataset, the natural and anthropogenic dust sources were identified. By combining the different scenarios of land use and climate, the dust emission processes under 15 scenarios from 1982 to 2020 were simulated, and the effects of climatic fluctuations (CF) and land use changes (LUC), which were roughly recognized as the natural and anthropogenic effects, respectively, on the variations in dust emissions were distinguished. The results showed that the annual dust emission quantities ranged from 41.12 to 240.68 Tg/a during the period. The natural dust sources (NDSs) and anthropogenic dust sources (ADSs) occupied an average of 13.30% and 59.77% of the total area of the QTP, respectively, and their contributions to the total dust emissions of the QTP were 8.11% and 91.89%, respectively. During these decades, the CF had an obvious trend of restraining dust emissions, while the effects of LUC promoted dust emissions, and after 2000, the promoted effect slowed down. Overall, the effects of LUC on dust emissions were slightly larger than those of CF. From the perspective of dust emission variations, we discussed the anthropogenic disturbance on the ecosystems of the QTP. We believe the study method can provide valuable references for identifying natural and anthropogenic sources and quantifying the effects of natural and anthropogenic factors on dust emission variations, and the results can reduce the uncertainty of the global dust budget.