Vegetation cover change and the driving factors over northwest China

In this paper the spatio-temporal variation of vegetation cover in northwest China during the period of 1982-2006 and its driving factors were analyzed using GIMMS/NDVI data. The annual average NDVI was increased with a rate of 0.0005/a in northwest China and there was an obvious difference between regions. The trend line slopes of NDVI were higher than 0.0005 in the Tianshan Moutains and Altay Mountains of Xinjiang, the Qilian Mountains of Gansu and the eastern part of Qinghai, which indicated the vegetation cover was significantly increased in these areas. The trend line slopes of NDVI were lower than -0.0005 in the southern region of Qinghai, the border regions of Shaanxi and Ningxia, the parts of Gansu and Tarim Basin, Turpan and Tuoli in Xinjiang, which indicated the vegetation cover was declined in these areas. The NDVI of woodland, grassland and cultivated land had an ascending tendency during the study period. The study shows that the vegetation cover change was caused by both natural factors and human activities in northwest China. The natural vegetation change, such as forests was influenced by climate change, while human activities were the main reason to the change of planting vegetation. The changes of vegetation covers for different elevations, slopes and slope aspects were quite different. When the eleva- tion is exceeded to 4,000 m, the NDVI increasing trend was very low; the NDVI at the slope of less than 25~ was increased by the ecological construction; the variation of NDVI on sunny slope was stronger than that on shady slope. The temperature rose significantly in recent 25 years in northwest China by an average rate of 0.67^-C/10a, and precipitation increased by an average rate of 8.15 mm/10a after 1986. There was positive correlation between vegetation cover and temperature and annual precipitation changes. Rising temperature increased the evaporation and drought of soils, which is not conducive to plant growth, and the irrigation in agricultural areas reduced the correlation between agricultural vegetation NDVI and precipita- tion. The improvement of agricultural production level and the projects of ecological construction are very important causes for the NDVI increase in northwest China, and the ecological effect of large-scale ecological construction projects has appeared.

The Theoretical Explanation of Non-ecological Economic Qualities of the Development Mode of Industrial Civilization:An Analysis Based on the Critical Perspective

The development mode of industrial civilization has created huge material wealth for human society,but at the same time the severe ecological problems that have arisen from it have made human civilization fall into the dispersion of unsustainable development.The industrialized development mode has obvious non-ecological economic qualities,which are specifically manifested in the destruction of the ecological economy relationship between nature and mankind,the emergence of cracks of metabolism between nature and mankind,the unbalanced development of the social productive forces and the natural productive forces,and the functioning of one-way linear non-circular economy.Under the trend of ecological evolution of human civilization,the industrial civilization will be replaced by the ecological civilization,and then the industrial economic development mode will be transformed into the ecological economic development mode.As a result,the predicament of once unsustainable development has been gradually dispersed and human civilization enters a beautiful new era of coordinated development of economic society and natural ecology.