Exploring global interdependencies from the hydrological cycle to virtual water flows through a network analysis

Freshwater is fundamental to Earth system processes, yet its global dynamics are often overlooked in water governance. With half of all terrestrial precipitation originating from land evaporation, the global interdependencies of atmospheric moisture flows remain underrepresented in policies addressing water security and climate adaptation. In particular, its impacts on global supply chains have not been assessed so far. Therefore, we here assess the interactions between the global network of atmospheric water with the international trade network, which we quantify by virtual water trade embedded in agricultural commodities. We conceptualise country-scale dependencies across three dimensions:

i) Geopolitical, examining how countries source and receive water through interconnected moisture networks;

ii) Physical, relating water scarcity and hydrological stress to network characteristics;

iii) Virtual, revealing dependencies and potential impacts from atmospheric moisture transport to virtual water flows.

In this work, we build on a previous dataset of bilateral atmospheric moisture flows, which has been reconciled to close the water balance, as well as an established virtual water trade network to construct global networks that quantify countries' roles and vulnerabilities in the hydrological cycle through network measures. Preliminary findings highlight key hubs and dependencies within these coupled networks, demonstrating that atmospheric moisture flows underpin both regional water security and global water governance. Our study advances the understanding of the interconnectedness of atmospheric and virtual water flows, linking physical and economic water systems to support sustainable water resource management globally.