Study On Green Efficiency And Promotion Path Of Regional Water-Energy-Food System

The relationship between water-energy-food system is a hot issue at home and abroad.Three resource elements form a whole system,that is,the community of waterenergy-food destiny.Fully understanding and paying attention to the relationship between water,energy and food system will help to fundamentally find a reasonable way to improve the utilization efficiency of resources,and then reasonably improve the utilization mode and safety utilization efficiency of resources.Improving the overall utilization efficiency of water-energy-food system and the positive benefits of economic and social output,and reducing the negative benefits of environmental pollution will be conducive to ensuring regional resource security and achieving the goal of regional sustainable development.Taking water-food-energy as a system and understanding its internal correlation is an effective way and an important means to solve the efficiency problems of water,energy and food system.However,at present,the development status and promotion path of this system efficiency are still in the exploratory stage.Under this background,this thesis studies the green efficiency,influencing factors and promotion path of regional water-energy-food system.By analyzing the driving force,pressure,state,influence and response of regional water energy grain system,WEF-DPSIR model is constructed,and regional re clustering and division are carried out;Green efficiency and factor contribution of regional water energy food system are measured from static and dynamic aspects;The path,direction and degree of the main influencing factors on the green efficiency of water energy grain system are analyzed;The system dynamics model of green efficiency of water energy grain system is constructed,and the path and policy scheme of improving the efficiency of water energy food system are formed.The core contents and basic conclusions are as follows.(1)The WEF-DPSIR conceptual model is established to re-cluster and divide 30 provinces and cities in China.The results show that the differences of clustering results are significant when the number of clusters is different.When the number of clusters is four groups,the overall clustering results in three time periods of 2004-2010,2011-2015 and 2016-2019 are relatively stable.The clustering results do not fully reflect the geographical proximity.Compared with the traditional research efficiency of regional grouping division,the clustering purpose of this thesis focuses on the green development of WEF system,and emphasizes the importance of the main factors affecting the green development efficiency of regional WEF system to regional division.Targeted clustering of provinces can not only improve the similarity of provinces within the group,but also ensure the significant differences among groups,effectively avoid the one-sidedness of grouping based on a single factor,and improve the comparability of green efficiency of WEF system.(2)The Meta-SBM-DDF model is constructed to analyze and decompose the green efficiency of WEF system.The green efficiency of WEF system can effectively measure the economic,social and environmental effects of water,energy and food resources utilization.From 2004 to2019,the overall green efficiency of China’s WEF system shows a fluctuating downward trend,and the overall level of inefficiency,input factors and output factors show a rising trend.The average green efficiency of WEF system from 2004 to 2019 is 0.587,the first group represents the best technology frontier of green production,while the fourth group is the low efficiency area.Among them,Beijing,Tianjin,Shanghai and Guangdong Province are in the best frontier during the research period,while other provinces do not reach the best frontier technology during the research period.In terms of factor contribution,the contribution rate of input factors and output factors is 22.8% and 18.5%respectively,which is the main reason for the overall inefficiency.(3)The Meta-Luenberger index model is constructed to analyze and decompose the green efficiency growth of WEF system.From 2005 to 2019,China’s WEF system green efficiency change index(GLTFP)showed a fluctuating downward trend,with an average annual decline rate of 6.43%,in which the annual change of technological progress was 7.74%,and the annual decrease of technical efficiency was 1.31%.The growth of GLTFP was mainly driven by technological progress.The GLTFP growth rate of Gansu,Sichuan and Heilongjiang ranks the top three,while that of Qinghai,Ningxia and Xinjiang is the lowest.GLTFP of the four groups showed an increasing trend,but the growth gap between regions was obvious: the third group > the second group > the first group > the fourth group.GLTFP growth is mainly driven by the change of input factor productivity.The average annual value of GLTC is 0.077.The change of input factor productivity is the core factor to promote the growth of GLTC.The average annual value of GLTEC is-0.013,The change of output factor productivity is the core factor to promote the negative growth of GLTEC.(4)The influencing factors of green efficiency of WEF based on spatial effect are analyzed.During the study period,the influencing factors have obvious spatial diffusion effect on the green efficiency of WEF system.If the green efficiency of WEF system in adjacent areas is higher,the green efficiency of WEF system in this region will be higher.When the inertia of green efficiency of regional WEF system is considered,the spatial effect of green efficiency of WEF system is obviously weakened.During the study period,the influencing factors on the green efficiency of WEF system are: economic system factor >Science and technology education factor > resource endowment factor > structure factor.The factors in the same direction as the green efficiency change of WEF system are: water resources endowment,proportion of science and technology expenditure of local finance,proportion of education expenditure,government influence,and proportion of industrial pollution control investment;The reverse factors to the green efficiency change of WEF system are: energy endowment,the proportion of secondary industry,the proportion of coal resource consumption,urbanization rate and per capita GDP.(5)The green efficiency promotion path of WEF system under the influence of influencing factors is simulated.Different promotion paths based on key factors can improve the green efficiency of WEF system in different degrees.The efficiency improvement ability of each scenario is as follows: comprehensive promotion scenario > single factor promotion scenario >benchmark scenario.The efficiency improvement ability of each parameter is as follows:The results show that the investment ratio of industrial pollution treatment > the proportion of secondary industry > government influence > per capita GDP > the proportion of coal consumption > the proportion of science and technology expenditure >the proportion of education expenditure > the per capita water resources > the water consumption of the secondary industry > the per capita energy production > the urbanization rate.Among them,the efficiency improvement effect of industrial pollution control investment is the most effective management tool that can be used for a long time.Comprehensive promotion scenario is the best path to promote green efficiency of WEF system.The main contributions of this thesis are as follows:Firstly,the WEF-DPSIR conceptual model was established,and 30 provinces,autonomous regions and municipalities in China were clustered and re-divided by factor analysis and cluster analysis,and four regional cluster groups based on WEF system correlation were formed.Considering the technical heterogeneity among the stability of water-energy-food resources,the coordination of relations and the sustainability of external environment among regions,changing the way of studying the input-output efficiency of water-energy-food according to the traditional regional division,fully incorporating the main factors that affect the green development efficiency of regional water-energy-food system,selecting 57 basic indicators from 9 subsystems in 3 aspects,and establishing WEF-DPSIR comprehensive evaluation index system,Using factor analysis and cluster analysis,30 provinces,autonomous regions and municipalities in China were clustered and regrouped,forming four groups that can reflect WEF correlation,realizing and improving the comparability of green efficiency of China’s regional WEF system.Secondly,the common frontier-non-radial SBM direction distance function model with unexpected output and Luenberger index model with global reference are constructed.According to the progressive way of "static analysis-group difference comparison-dynamic analysis-factor productivity-factor contribution identification",the element source and contribution of WEF system green efficiency and growth are revealed.Based on the multi-input and multi-output index system,the Meta-SBM-DDF and MetaLuenberger index models are constructed,and the green efficiency and green efficiency growth rate of the whole and four groups are measured from the static and dynamic perspectives,respectively,and the specific contribution of input and output factors to promoting efficiency and efficiency growth is decomposed horizontally and vertically.On the one hand,it realizes the traditional horizontal decomposition,discusses the technological progress and technical efficiency improvement,on the other hand,it realizes the vertical decomposition of the contributions of various input and output elements,and answers the specific contribution degree of input and output elements to promoting efficiency and efficiency growth.Thirdly,the influencing factor model of WEF system green efficiency based on spatial effect is constructed,and the path to improve WEF system green efficiency based on influencing factors is put forward.Based on the spatial econometric model,a model of influencing factors of green efficiency based on spatial effect is constructed,and the influencing mechanism,direction and intensity of resource endowment factors,science and technology education support,economic system factors and structural change factors on the green efficiency of China’s water-energy-food system are measured.On this basis,a system dynamics model of green efficiency of water-energy-food system is constructed,and the simulation of the path of improving green efficiency of WEF system based on influencing factors is established.Predict and compare the regulation effect of main influencing factors on the green efficiency of WEF system,put forward policy suggestions based on influencing factors,and realize the optimal choice of regulation path.