[关键词]
[摘要]
为真实反映地区水资源承载状况,需要从产业结构和商品贸易的角度分析地区虚拟水消费情况。以北京市为研究区,基于北京市投入产出表,对比分析2007、2012、2017年不同生产部门用水系数、虚拟水终端消费和贸易情况以及部门间虚拟水转移量。结果表明:随着北京市节水工作的推进,各部门的直接用水系数减小,近10年北京市虚拟水终端消费量减少14%;作为虚拟水净流入城市,北京市虚拟水净流入量为29.79 亿m3,占虚拟水终端消费量的64.7%,其中农业和服务业分别是虚拟水最大净流入和净流出的部门;农业制造业、农业服务业、制造业建筑业、制造业服务业具有很强的虚拟水输出输入关系,未来北京市节水工作不仅要减少农业的生产规模,而且要减少制造业、建筑业和服务业的产品消耗,减少终端消费浪费。
[Key word]
[Abstract]
Water scarcity has become a common global problem.As a mega-city,Beijing supports more than 20 million permanent residents with 2.16 billion m3 of local water resources.South-to-North Water Diversion and recycled water could resolve the crisis of water resource shortage of Beijing effectively,while virtual water flow with commodity trade has also changed the distribution of water resources in economic sectors and regions,and played an important role in alleviating water shortages.To fully reflect water resources bearing capacity,it is required to analyze the virtual water consumption and trade from the perspective of industrial structure and commodity trade. An urban virtual water accounting framework is proposed based on input-output table and the direct and complete water consumption coefficients of the 8 major departments of Beijing in 2007,2012 and 2017 are analyzed under the background of industrial structure adjustment and watersaving work,as well as research the characteristics of sectoral virtual water consumption and virtual water flows among different sectors. From 2007 to 2017,the direct water use coefficient of all sectors in Beijing shows a downward trend,the direct and complete water use coefficient of agriculture are largest,and completer water use coefficient drops from 716 m3/¥1 000 in 2007 to 222.1 m3/¥1 000 in 2017,the multiplier for agricultural water use declines from 1.6 to 1.2 which indicates the impact of agricultural development has weakened the increase in water use in other sectors.The direct water use coefficient of transportation,construction,and manufacturing sectors are small,but the water multiplier is large,and the increase in unit products of these will bring about water consumption in other sectors.In the past 10 years,the total local end use of virtual water has dropped from 5.37 billion m3 to 4.5 billion m3,the virtual water consumption in the service industry accounts for total virtual water consumption decreases from 32.8% to 30%,and the proportion of agriculture rises from 21% to 39%.As a net imputer of virtual water,the net virtual water imports of Beijing increases from 2.88 billion m3 to 2.98 billion m3 which accounts for more than 50 %of the final demand.Although agriculture consumes the most virtual water,it mainly relies on imputs from other provinces to meet the needs of Beijing.A comparative analysis of virtual water flows between 8 sectors in 2007 and 2017,it is found that the virtual water flow pattern remains unchanged,agriculture,mining,and water supply are the virtual water output sectors while construction,transportation,and service are the virtual water imput sectors.The net output of virtual water from agriculture is 982 million m3 in 2017,and the flow to manufacturing and service is 640 and 230 million m3,respectively.There are obvious outflow-inflow pairs,includig agriculture-manufacturing,agriculture-service,manufacturing-construction,manufacturing-service,manufacturing-transportation,and service-construction. With the advancement of water saving work and the improvement of water use efficiency,the direct water use coefficient of various departments has decreased,and virtual water consumption of Beijing has declined 14% in the past 10 years.The pressure on water resources could be relieved to some extent due to imput agriculture and mining with high water consumption and output service industry with low water consumption.In the future,watersaving work in Beijing will not only control the scale of water consumption in agriculture with large direct water use coefficients but also need to pay attention to the implementation of water-saving measures in the transportation,construction,manufacturing,electrical supply,and service industries.At the same time,it′s necessary to strengthen the management of water resources at end-users and reduce waste of products.
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[基金项目]