Assessing the relative role of climate change and human activities in desertification of North China from 1981 to 2010

Desertification is a severe environmental problem induced by both climate change and human activities. This study assessed the relative contribution of climate change, human activities, and different climatic and anthropogenic factors in desertification reversion and expansion of North China from 1981 to 2010. The results showed that the desertification of North China had changed significantly over the past 30 years; desertification reversion and expansion covered an area of 750,464 km(2), and the spatial distribution of these regions exhibited considerable heterogeneity. For desertification reversion, climate change and human activity accounted for 22.6% and 26%, respectively of total reverted land. Wind speed reduction and the improvement of hydrothermal conditions were the most important climatic factors for desertification reversion in the arid region of Northwest China (ARNC) and the Three-River Headwaters region (TRHR), and the reduction in grassland use intensity was the most important anthropogenic factor related to desertification reversion in Inner Mongolia and regions along the Great Wall (IMGW). For desertification expansion, the relative role of climate change was more obvious, which was mainly attributed to the continuous reduction in precipitation in eastern IMGW, and the increase in grassland use intensity was the main factor underlying regional human-induced desertification expansion.