Revealing the nexus profile of agricultural water–land–food–GHG flows in China

Revealing the nexus between agricultural water, land, and greenhouse gases (GHGs) associated with food trade is important for the harmonious development of agricultural resource elements and the guarantee of food security. In this study, we develop a water-land-food-GHG (WLFG) nexus to portray the virtual water, virtual land, and embodied GHG transfers associated with the food trade considering China's three major food crops (rice, wheat, and maize) by combing environmentally-extended multi-region input-output model with Penman-Monteith equation, crop coefficient method, and IPCC coefficient method. The WLFG coupling coordination relationship was further explored for proposing policy recommendations on the synergy optimization of WLFG. The results showed source structure similarities between crop water requirements and agricultural GHG, with virtual water, land and embodied GHG flows related to the food trade patterns. In 2017, China's total virtual water, virtual land, and embodied GHG transfer flows were 376.85 billion m3, 88.17 million ha, and 391.89 Mt CO2-eq respectively, increasing by 28.42%, 33.25%, and 55.2% compared to 2007. Overall, China's average WLFG coupling coordination rises slightly on both supply and demand side. This study provides guidance for the synergistic management and sustainable development of agricultural WLFG nexus system.