Mapping water scarcity risk in China with the consideration of spatially heterogeneous environmental flow requirement

Abstract

Water is an indispensable raw material for industrial production across various economic activities. Extensive research indicates that local water scarcity may cause severe economic output losses, posing risking not only to the affected regions (referred to as local water scarcity risk, LWSR) but also to distant regions through trade networks (known as virtual water scarcity risk, VWSR). To assess water scarcity risk (WSR), a key metric used is the environmental flow requirement (EFR), which exhibits considerable spatial heterogeneity. However, previous studies have primarily employed a constant EFR value (approximately 80%), limiting the reliability of the WSR findings. To address this limitation, we propose a comprehensive framework that incorporates spatially heterogeneous EFR. Our analysis reveals that in 2017, the WSR in China amounted to over 3.9 trillion US dollars, consisting of 1.6 trillion dollars attributed to LWSR and 2.3 trillion dollars to VWSR. Through examination at provincial, sectoral, and trade-link levels, we identify specific WSR hotspots and present relevant policy implications. Additionally, by comparing our results with those obtained using the 80% EFR criterion, we uncover significant differences. These findings emphasize the importance of considering spatially heterogeneous EFR and contribute to more accurate evaluations of WSR.