The water footprint of staple crop trade under climate and policy scenarios

Abstract

Trade in staple crop commodities has become increasingly important in the global food system, with ramifications for both food security and water resources sustainability. It is thus essential to understand how the water footprint (WF) of staple crop trade may change in the future. To this end, we project international staple crop trade and its WF under climate and policy scenarios for the year 2030. We use the H08 global hydrologic model to determine the impact of climatic changes to staple crop yields and evapotranspiration. Using the yield changes projected with the H08 model, we estimate the bilateral trade of staple crops using the Global Trade Analysis Project model. We combine these projections to obtain the total and blue WF of agricultural trade and global water savings (GWS) across scenarios. This approach enables us to determine the direct impact of climate change and trade liberalization—together and in isolation—on the WF of staple crop trade. Importantly, we show that trade liberalization leads to greater WF, making it a potentially important adaptation measure to a changing climate, although future work is needed to distinguish high resolution crop water use, water stress, and commodity transfers.