Laboratory for Earth Surface Processes, Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
School of Public Affairs, Zhejiang University, Hangzhou 310058, Zhejiang, China.
Sci Total Environ. 2022 Jul 1;828:154493. doi: 10.1016/j.scitotenv.2022.154493. Epub 2022 Mar 10.
With the increasing contradiction between water demand and supply in a telecoupled society where nature and human interplay intensively over distance, virtual water trade (VWT) plays an indispensable role in global water use sustainability. There has been little quantitative analysis of global water use sustainability depicting both overall system characteristics and flows between subsystems. In such a context, the extent to which virtual water transfer deviates from possible ideal expectations (i.e., virtual water flows from water-abundant regions to water-scarce ones), and its impact on global water use sustainability, are not well evaluated. Therefore, the global VWT vulnerability framework is proposed to delineate the gap between the real VWT and the possible optimal scenario, providing potential space for future optimization and regulation. Represented by the ratio of weighted total virtual water volume to the original one, the vulnerability is assessed from 2005 to 2015 based on the Eora input-output database and Virtual Water Transfer Multiplier which assigns differentiated weights to per unit volume of virtual water transfer based on the water stress levels of importers and those of exporters. Results show that the global VWT vulnerability has increased by 18.9% during the study period, with Africa and Southern and Central Asia making the biggest contribution. Developed countries contributed around 80% of the increased global VWT vulnerability. However, the proportion has fallen a bit, in terms of the conventional view of developed countries taking the approach of transferring responsibility to developing countries. Instead, the proportions of transferring responsibility between developing countries have rose by 10% to 30% during 2005-2015, partially due to stronger trade ties among developing countries. Our findings support policy decisions on tracing environmental responsibility for water scarcity and call for action to prevent water ecological downsides due to international trade.
在一个自然与人类远距离相互作用的电信社会中，水的需求和供应之间的矛盾日益加剧，虚拟水贸易（VWT）在全球水资源可持续利用中发挥着不可或缺的作用。目前，很少有对全球水资源可持续性进行定量分析的研究，这些研究既描绘了整个系统的特征，又描绘了子系统之间的流动。在这种情况下，虚拟水转移偏离可能的理想预期的程度（即，从水资源丰富的地区向水资源匮乏的地区转移虚拟水）及其对全球水资源可持续性的影响，还没有得到很好的评估。因此，提出了全球虚拟水脆弱性框架，以描绘真实虚拟水与可能的最优情景之间的差距，为未来的优化和监管提供了潜在的空间。脆弱性用加权总虚拟水体积与原始虚拟水体积的比值来表示，根据 Eora 投入产出数据库和虚拟水转移乘数来评估 2005 年至 2015 年的脆弱性，虚拟水转移乘数根据进口国和出口国的水压力水平为每单位虚拟水转移分配不同的权重。结果表明，在研究期间，全球虚拟水脆弱性增加了 18.9%，非洲、南亚和中亚的贡献最大。发达国家约占全球虚拟水脆弱性增加的 80%。然而，从发达国家将责任转移到发展中国家的传统观点来看，这一比例略有下降。相反，2005-2015 年期间，发展中国家之间转移责任的比例上升了 10%至 30%，部分原因是发展中国家之间的贸易联系更加紧密。我们的研究结果支持关于追踪水资源短缺环境责任的政策决策，并呼吁采取行动防止因国际贸易而产生的水生态负面后果。
