Global supply chain drivers of scarce water caused by grain production in China

Water scarcity, characterised by both inadequate supply and deteriorating quality, poses substantial challenges to grain production. Despite being the largest consumer of water, the global supply chain factors driving water utilisation for specific grain crops are often overlooked. This oversight impedes the development of targeted water conservation policies. This study employs a high-resolution, scarce-water extended multi-regional input-output model to examine the drivers of grain-related scarce water (GRSW) usage in China, analysing it from production, demand, and supply perspectives. The results indicate that China's grain production consumed 2308 billion cubic metres of GRSW in 2014. On the demand side, 97 % of this water usage was attributed to domestic consumers, with significant contributions from Shandong, Hebei, Henan, and Jiangsu provinces. Additionally, the demand of products from China's food manufacturing, accommodation, and catering sector by Japan, the United States, and South Korea markedly influences GRSW utilisation in China. From the supply perspective, the grain sectors in Shandong, Hebei, and Henan serves as the primary domestic suppliers. Our findings highlight the critical nodes within the global supply chain that contribute to GRSW usage and elucidate the roles of various socioeconomic activities, offering valuable insights for policymakers from multiple perspectives to effectively address GRSW issues in China.