干旱区生态环境知识资源中心

Based on three phases of satellite-image data and field investigation results collected between 1976 and 1996, climate changes and intensity of human activity were studied for the time period to investigate the causes responsible for the region’s environmental changes. The results show that, compared with the data for the 1970s, the eco-environment in the source region of the Yellow River degraded markedly from the 1980s to the 1990s. Degradation was most prominent from the mid-1990s onward, with significant degradation of high-cold grassland and high-cold meadow vegetation and also a rapid expansion of desertification. The area of degraded vegetation increased from 24.5% in the 1980s to 34.5% of total grassland and high-cold meadow in the 1990s. The rate of land desertification increased from 3.96% in the 1980s to 34.72% in the 1990s. The main reasons for these changes include the intensity of overgrazing ( which was very high), and the climate in this region which is becoming drier and warmer, resulting in a gradual degradation of the permafrost.