Empirical study on sustainable development based on the three-dimensional ecological footprint：A case of Chongqing

Chongqing is located in southwest China, the upper reaches of the Yangtze River, with a total karst area of 32，680 km2, accounting for 39.7% of the city’s land area. Due to its poor internal environmental stability, the area has serious ecological problems such as soil erosion and rocky desertification. In recent years, relying on its superior location and national strategic advantages, Chongqing has basically formed a pattern of coexistence of large agriculture, large industry, large transportation and large circulation. With the rapid economic and social development, the ecological environment is facing tremendous pressure and the sustainable development has been threatened. In order to provide references for the sustainable development of Chongqing,in this paper, we firstly adapted the 3D ecological footprint model of Niccolucci by calculating the "national hectare", updating the equilibrium factor and yield factor, and adding the pollutant account. Then, we diachronically analyzed the ecological footprint of Chongqing from 2008 to 2017 by using the improved ecological footprint model. On this basis, we constructed a comprehensive index to assess the dynamic changes of sustainable development ability in Chongqing. The results show that， （1） The stock flow indexes were less than 1 in the period studied, except for those in the years of 2008, 2012, 2013 and 2014, indicating that the consumption of stock capital has decreased; （2） The overall ecological resource utilization efficiency index decreased year by year, while the resource utilization efficiency increased at the same time; （3） The index of ecological diversity increased stepwise, and the stability of the ecosystem was enhanced; （4） The comprehensive index of sustainable development capacity increased by 13.85%, indicating that the overall sustainable development capacity has been strengthened; （5） The ecological pressure index was between 1.51 and 2.00, the ecological environment was still in a very unsafe state, the stock capital was still occupied, and Chongqing was still in a state of unsustainable development. In addition, the comprehensive index of sustainable development capacity showed a slight decline in 2017. Therefore, under the guidance of the concept of "green water and green mountains are golden mountains and silver mountains", Chongqing should accelerate the formation of a spatial pattern of resource conservation and environmental protection, strive to build an environmental governance system led by the government, dominated by enterprises, and jointly participated by social organizations and the public, optimize the ecological spatial layout, strictly abide by the three control lines, and be alert to the continuous decline of sustainable development capacity.