Improved assessment of water-saving effects by global virtual water flow in agri-food trade network with an integrated approach

Agri-food trade redistributes virtual water globally, reshaping water stress patterns, while water-saving effects vary among virtual water trade networks. A gap in accurately quantifying virtual water flows and assessing their impact on national water resources still exists, which is essential for achieving sustainable development. This study proposes an integrated approach to improve the assessment of virtual water trade in the global agri-food system. The framework comprises three key modules: a water footprint module, a product equivalent conversion module, and a virtual water flow module. By incorporating higher spatial resolution and extending the analysis period from 2000 to 2020, this approach significantly improves the accuracy of virtual water-saving effects (VWSE) estimation. Additionally, it enhances precision by tracing virtual water consumption back to its origin. An overestimation of virtual water flow volumes based on bilateral trade data was observed, increasing from 9.21 % to 12.53 %. Results indicate that the VWSE of global agri-food trade is mostly positive, with a maximum of 42.74 x 1010 m3 in 2016, reflecting a 39.7 % increase from 2000 to 2020. In 2020, agri-food trade wasted 83.80 x 1010 m3 and saved 121.27 x 1010 m3 of virtual water globally, respectively. Among the 35,910 trade routes assessed from 2000 to 2020, the proportion of negative VWSE routes increased from 43 % to 49 %. Among all traded commodities, cereal exhibited the highest gross positive VWSE, accounting for 50.6 % of the global total. In 2020, agri-food trade significantly alleviated water stress ratio in 70 % of countries. This assessment informs trade policy design and provides insights for future international cooperation on sustainable development. Regulatory measures that consider both water use efficiency and resource endowments are necessary to optimize resource use in future agri-food trade.