Water saving through international trade of agricultural products
Water saving through international trade of agricultural products
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DOI：
10.5194/hess-10-455-2006
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发表时间：
2006-01-01
影响因子：
6.3
通讯作者：
Savenije, H. H. G.
中科院分区：
文献类型：
--
作者：
Chapagain, A. K.;Hoekstra, A. Y.;Savenije, H. H. G.
许多国家通过进口耗水产品和出口耗水较少的商品来节约国内水资源。如果从用水效率高的地点流向用水效率低的地点，通过进口一种产品实现国家节水就意味着在全球范围内节约用水。本文分析了国际虚拟水流量对全球和各国水预算的影响。评估表明，如果所有进口农产品都在国内生产，进口国所需的总水量为1605 Gm(3)/年。然而，这些产品在出口国的产量仅为1253克/年，每年为全球节约水资源352克/年。这一节约相当于与农产品贸易有关的国际虚拟水流量的28%和全球农业用水的6%。然而，国家决策者感兴趣的不是全球节水，而是国家水资源的状况。埃及进口小麦，这样做每年节省3.6 Gm(3)的国家水资源。用于生产出口商品的用水可能是有益的，例如在科特迪瓦、加纳和巴西，利用绿色水资源（主要通过雨养农业）生产用于出口的兴奋剂作物对国民经济产生了积极的经济影响。然而，泰国每年与大米出口相关的28 Gm(3)国家水的出口是以对其蓝水资源施加额外压力为代价的。进口绿色虚拟水与蓝色虚拟水比例较高的产品，可以节约全球蓝水资源，而蓝水资源的机会成本通常高于绿水资源。
Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water productivity. The paper analyses the consequences of international virtual water flows on the global and national water budgets. The assessment shows that the total amount of water that would have been required in the importing countries if all imported agricultural products would have been produced domestically is 1605 Gm(3)/yr. These products are however being produced with only 1253 Gm(3)/yr in the exporting countries, saving global water resources by 352 Gm(3)/yr. This saving is 28 per cent of the international virtual water flows related to the trade of agricultural products and 6 per cent of the global water use in agriculture. National policy makers are however not interested in global water savings but in the status of national water resources. Egypt imports wheat and in doing so saves 3.6 Gm(3)/yr of its national water resources. Water use for producing export commodities can be beneficial, as for instance in Cote d'Ivoire, Ghana and Brazil, where the use of green water resources (mainly through rain-fed agriculture) for the production of stimulant crops for export has a positive economic impact on the national economy. However, export of 28 Gm(3)/yr of national water from Thailand related to rice export is at the cost of additional pressure on its blue water resources. Importing a product which has a relatively high ratio of green to blue virtual water content saves global blue water resources that generally have a higher opportunity cost than green water.