Land degradation and restoration in the arid and semiarid zones of China: Quantified evidence and implications from satellites

Abstract Quantified information on land degradation and restoration is needed to support policies for sustainable ecosystem management and socioeconomic development. The arid and semiarid zones of China (ASZC) have experienced significant land degradation, and in response to such degradation, multiple ecological projects were implemented. In this study, remote sensing was used to identify degrading areas and where the degraded areas have been restored from 1990 in this ecologically sensitive region. Specifically, we integrated datasets from the ChinaCover and Moderate Resolution Imaging Spectroradiometer products to characterize changes in vegetation, ecosystems, and environmental conditions. The results confirmed that deforestation, desertification, grassland degradation, wetland loss, and the encroachment upon farmlands were notable in the ASZC. Agricultural activity has cultivated extensive areas of natural ecosystems (46,474 km 2 ). The expansion of built‐up lands in terms of national policies has destroyed large areas of natural (5,487 km 2 ) and agricultural (4,138 km 2 ) ecosystems and continually results in negative impacts on ecological conservation. China has restored some lands (7,732 km 2 from farmlands and 24,904 km 2 from barren lands) and improved ecosystems, as characterized by increases in the normalized different vegetation index, leaf area index, net primary productivity, and gross primary productivity values in the ASZC, especially after the implementation of many ecological projects. However, it is also necessary to document the conclusions and lessons from these projects to guide future ecological policies and projects in the context of the substantial new challenges facing the protection of this ecologically sensitive environment.