Social network analysis of virtual water trade among major countries in the world.

This study utilizes multi-region input-output model to calculate the virtual water trade among 19 major countries (the Group 20 countries, except the EU) from 2006 to 2015. Moreover, this paper uses network analysis method to study the characteristics of virtual water trade networks. Results show that: (1) the import and export of the virtual water trade among 19 major countries in 2015 increased in varying degrees. Among them, the growth rates of China's import and Russia's export were the highest. (2) The density(average value) and asymmetry(differences between import and export)of the virtual water trade network among the major countries in 2006-2015 increased throughout the whole industry and the three major industries. In comparison with the secondary and tertiary industries, the virtual water trade network formed by the primary industry is denser. (3) The Out-Degree(corresponding to export) and In-Degree(corresponding to import)of countries in the virtual water trade network of the whole industry increased in varying degrees in 2015. Major countries exhibited the largest export and import within the primary industry, except for Japan and South Korea. Therefore, in order to alleviate the contradiction between supply and demand of water resources in various countries, it is necessary to further strengthen the construction of transportation facilities and reduce the logistics cost of trade in industrial and agricultural products, especially the trade cost of agricultural products such as grain, so as to further expand the virtual water import and export trade to expand the import and export trade of the virtual water network further.