Research On The Changes Of Material Stock Pattern And The Impact Of Eco-environment During The Process Of Urbanization In Shenzhen

China is currently in an accelerated period of urbanization development,and Shenzhen is the first and only city in China to achieve 100% urbanization.The sustainable development of the city is restricted by gradually decreasing resources and deteriorating ecological environment.Changes in the material flow of urban infrastructure and durable goods within a country or a region can reflect the resource consumption and environmental impact resulted from economic and social development,it can also reflect the level of sustainable development.The researches of the urban material stocks in infrastructure system has become a hot spot in the study of socio-economic metabolism in urban ecology.Exploring the evolution laws and driving mechanism of Shenzhen’s material stock as well as identifying the following effect on the resources consumption and environmental deterioration is essential to promote the sustainable development of Shenzhen and accelerate the ecological civilization construction.This research took Shenzhen as the research object and used the bottom-up material flow analysis（MFA）to explore the patterns and evolution laws of material stocks contained in 9 types of infrastructure and 12 types of consumer durable goods in the process of urbanization from year 2000 to year 2019.The driving force of social economic indicators including population,economy and technology which were highly related to the urbanization imposed on the stock was then analyzed by using IPAT equation.Additionally,the potential effect on resources consumption,energy consumption and ecological environmental brought by material net inflow（input）was figured out.Through the above research,I hope to put forward some suggestions concerning material stock management in order to improve the sustainability of the city.The main conclusions of this study are as follows:（1）The material stock of infrastructure and household durable goods in Shenzhen was rising steadily.The total material stocks in Shenzhen increased from 124 million tons in year 2000 to 336 million tons in year 2019.The average annual growth rate is5.7%.Of the nine types of infrastructure,the stock in building system contributed to the largest share,accounting for 92.3% on average.The stock in taxi took the least share.The stock of gravel possessed the largest proportion,followed by steel.Among the 12 household durable goods,the amount of the household car occupied the largest proportion which is up to 76.63% generally.The main materials of a car are steel and plastic,the steel accounts for a huge part.（2）The key driving factors for the growth of Shenzhen’s material stock were population and economy.The population,compared with other factors: economy and technology,imposed more effect on the strength of the material stocks.The effect of technology on material stock is shown as slowing down the growth of material stock to some extent,and it is predicted that this trend will still exist in the future.（3）The potential impact of Shenzhen’s material stock on the ecological environment was significant.The result of LCA of steel and cement demonstrate that human non-carcinogenic toxicity,global warming,marine ecotoxicity,human carcinogenic toxicity,mineral resource scarcity,terrestrial ecotoxicity,and fossil resource scarcity were the most significant impact types.（4）We put forward three policy suggestions for Shenzhen’s material stocks.We attempt to put forward policy recommendations related to the material inventory management,scarp recycling and ecology process optimization in order to accelerate the sustainable development of Shenzhen.