Quantitative Evaluation of the Impacts of Climate Change and Human Activities on Wind Erosion: A Case Study of Inner Mongolia in China

Abstract

Soil erosion by wind is a critical problem causing land degradation in the arid and semi-arid areas in China. Climate change and human activities are two driving forces of wind erosion. For regional wind erosion assessment, it is essential to quantitatively evaluate the impacts of climate change and human activities. The variable control method is widely used for quantitative estimation of the driving forces of wind erosion at different spatial and temporal scales. However, most of the previous studies classified the variation of wind erosion caused by vegetation changes to human activities. Without the consideration of climate change effects to vegetation, the evaluation of wind erosion driving forces is biased from the real situation. In this study, wind erosion was simulated in Inner Mongolia, northern China, from 2000 to 2019 with the observed temperature, precipitation, wind, land use and land cover, vegetation index, and soil data. The potential vegetation index was calculated using the residual trend method. The potential and actual wind erosion modulus were obtained based on the corresponding calculated potential vegetation index and the observed vegetation index using the empirical wind erosion models. The difference between the potential and actual wind erosion modulus was assumed to be the change caused by human activities. The quantitative assessment was conducted in this study to evaluate the relative impacts of climate change and human activities on wind erosion (Figure 1). <fig><graphic xlink:href=23101_files/23101-01.jpg id=ID_4b86b0b8-26ac-4b6e-b09e-efc2b43a6f2c></graphic></fig> The results showed that the total wind erosion amount was 51.73 billion tons for all of Inner Mongolia from 2000 to 2019. The wind erosion modulus decreased significantly within these 20 years and the average annual decline rate was 55.92 tons/(km²Â·year), which agreed with the previous studies (Zhang et al., 2018; Chi et al., 2018). Both climate change and human activities are key driving forces for the wind erosion changes in Inner Mongolia. For the regions with declining wind erosion rates, 33.6% and 23.1% of the areas were mainly caused by climate change and human activities, respectively. For the parts with increasing wind erosion rates, the percentages were 30.3% and 13.0% for climate change and human activities, respectively (Figure 2). <fig><graphic xlink:href=23101_files/23101-00.jpg id=ID_340f2590-c9ef-4307-a63d-93ccfc7b1136></graphic></fig> The decreasing wind erosion areas were associated with decreased wind speeds, increased precipitation, and the implementation of ecological protection projects. The increasing wind erosion areas were the result of increased wind speeds, overgrazing, and excessive cultivation during the 20-year period. This study separated the relative effects of vegetation caused by climate change and human activities on wind erosion, which improved the accuracy of driving forces assessment for regional wind erosion. Our study provided the theoretical basis and data support for wind erosion estimation and control in northern China.