Impact Of Human Activities And Climate Change On Agricultural Water Footprint In Beijing

With the rapid development of economic society and the accelerated urbanization process in Beijing,Beijing is facing water shortage,water pollution and other issues.Due to the green development demand,Beijing has a new challenge.As a high water consumption sector,this paper analyzed the agricultural sector water footprint of human activities drivers,explored the impact of climate change on water use stress.On the basis of this,this paper forecast the demand of agricultural water footprint under human activities and climate change,and then put forward the policy proposal to reduce the agricultural water footprint in Beijing.In this paper,the agricultural sector in Beijing as a research object,based on STIRPAT model analyzed the human factors of Beijing WF footprint and combined the standardized precipitation index(SPEI)and the Mann-Kendall test to study the change of Beijing climate.Finally,the radial basis function(RBF)neural network was used to establish the model to simulate the change of agricultural WF in Beijing under three different situations and provide the basis for the relevant policy formulation.The results show that the average annual agricultural WF in Beijing from 1980 to 2012 is 388.817 billion cubic meters,and its experience is the first to decline and then gradually stabilize until 2004.Nearly three decades the blue WF is far greater than the others.The proportion of blue WF is 50.43%,followed by gray WF and green WF,accounting for 29.55%and 20.02%respectively.It is found that the influence of Engel coefficient on the agricultural WF in Beijing is the largest,followed by population,the urbanization level,the per capita GDP and the total rural electricity consumption,the influence coefficient is 0.579,-0.201,0.096,-0.078,-0.02 respectively.The Mann-Kendall mutation test showed that the green WF was influenced by the maximum temperature and rainfall,while the blue WF was affected by the sunshine hours.Through the analysis of the drought characteristics of Beijing in SPEI,it is found that from the annual scale,the Beijing climate changed from wet to dry since the mid-90s.From the seasonal scale,Beijing spring and summer drought increased.From the view of climate change,the climatic factors of Beijing have changed frequently in the past 30 years.However,rainfall,relative humidity and sunshine hours are decreasing,which the M-K value is-0.77,-2.02,-4.21,the maximum temperature and the minimum temperature are increasing in the overall trend,which the M-K value is 1.21,2.41.The RBF neural network prediction of agricultural water footprint in Beijing under three different scenarios was carried out Under the climate drought situation,the impact of Beijing's agricultural water footprint is greater than whether the economic and population macroeconomic regulation and control scenarios.In order to alleviate the shortage of water resources in Beijing,it should be considered from three aspects:the optimization of agricultural planting structure,the development of new technologies for agricultural water saving and the functional area of ecological industry in Beijing.Planting low water consumption plants,the combination of technological innovation and industrial structure optimization,to explore the characteristics of Beijing with the agricultural production methods,and constantly increase the green ecological industry function construction,will become the key to the future of Beijing's agricultural water conservation.This study not only provides scientific basis for alleviating the shortage of water resources and exploring the green development in Beijing,but also provides new ideas and perspectives for the study and prediction of agricultural water footprint in other cities.