Spatio-temporal Pattern And Coupling Relationship Analysis Of Food-Energy-Water Security In China

Food,energy and water are essential basic resources for human survival and development.They are interconnected and constitute the food-energy-water(FEW)nexus,providing key ecosystem services for human livelihood and well-being.However,rapid population growth,urbanization,climate change,economic development and resource depletion are putting enormous pressure on FEW nexus at local,regional,national and global scales,which may lead to synergies or trade-offs between different sectors or interest groups and will also have an important impact on the development of the whole social economy.FEW nexus are therefore of particular concern in the area of resource security.Based on this,this paper takes the security and coupling coordination relationship of the FEW nexus as the research content,and discusses the spatio-temporal pattern,coupling relationship and influencing factors of the FEW nexus from the perspective of the system.The research has certain reference significance for the integrated management of system resources and the promotion of sustainable development.Firstly,the index evaluation system of food,energy and water system was constructed respectively to evaluate the security level and spatio-temporal pattern of the three subsystems from 1980 to 2020,and the spatial distribution pattern of food-energy-water security was identified by k-means clustering algorithm.Then,coupling degree and coupling coordination model were used to quantify the coupling relationships among food-water,energy-water,food-energy and food-energy-water,and the spatial visualization was carried out.Secondly,the spatial autocorrelation analysis and spatial econometric model were used to comprehensively explore the impact of multiple influencing factors(economic level,educational level,technological progress,economic agglomeration,population,agricultural and forestry support and basic resources)on the coupling coordination degree of food-energy-water in China.Finally,from the perspective of the relationship between FEW,this study tries to put forward some suggestions for improving the coupling coordination degree of FEW nexus in the future.Specific research results show that:(1)China’s food security index is generally on the rise.The provinces with higher food security index are mainly distributed in northeast China and Inner Mongolia Autonomous Region,while the food security level in southwest China is relatively low.Social and economic level has a greater impact on food security than climate factors,and the added value of the primary industry is the most important factor affecting food security level in China.The spatial pattern of energy security changes obviously,and the energy security index changes from high in the east and low in the west to high in the west and low in the east,showing a downward trend in the time series.The provinces with declining energy security index are mainly distributed in the eastern coastal region,while the provinces in the western region show an upward trend.The water stress index of China showed a downward trend as a whole,and there were significant regional differences in water stress.The north water stress was high,while the south water stress was low.Approximately 63%(843 million people)of the population live with at least severe water stress(WSI>0.2)and 32%(433 million people)live in areas of extremely water stress.The inequality degree of regional water resources stress is high and presents an upward trend.PLS regression analysis further reveals the spatial heterogeneity of water stress,and precipitation is the most important driving factor affecting water stress.(2)The degree of coupling coordination between the food-energy-water system and subsystems is in descending order: food-water,energy-water,food-energy-water and food-energy.Except that the coupling coordination degree of food-energy system is in the stage of barely coordination,the other three systems are in the stage of primary coordination.By 2019,Guangxi province had the highest coupling coordination of water-energy systems;The coupling coordination degree of water-food system is the highest in Heilongjiang and Guangdong Province;Yunnan province and Shaanxi Province have the highest coupling coordination degree of food-energy system.Hainan province has the highest coupling coordination degree of food-energy-water system.During the study period,the coupling coordination degree of food-energy-water showed an increasing trend in all provinces except Heilongjiang,Henan,Jiangsu,Anhui,Chongqing and Guangdong.(3)There is a significant positive correlation between the coupling coordination degree of FEW system,Moran index shows a fluctuating downward trend,and the spatial aggregation characteristics are weakened.The spatial aggregation patterns between the coupling coordination degree and the driving factors were different,and the spatial aggregation patterns were also different in different years,indicating that the spatial aggregation patterns were unstable.During the analysis of influencing factors,six driving factors have statistical significance.Among them,non-agricultural output per unit area has a negative impact on the coupling coordination degree of FEW in China,while the number of patent authorization,financial expenditure on agriculture and forestry,per capita GDP,population and education as a percentage of GDP proportion have a significant positive correlation with the coupling coordination degree.Per capita GDP is the most important driving factor affecting the coupling coordination degree of food-energy-water in China.