Non-negligible regional differences in the driving forces of crop-related water footprint and virtual water flows: A case study for the Beijing-Tianjin-Hebei region

Abstract

Water scarcity is a significant risk for meeting increasing food demand around the world. The importance of identifying the driving forces behind water consumption in agriculture and relative virtual water (VW) flows has been widely reported in order to provide practical advice for regional sustainable agricultural water resource management. However, the differences of regional driving forces behind both water consumption and VW flows were largely ignored. To fill the crucial gap, taking nine major crops grown in the Beijing-Tianjin-Hebei (BTH) region in China over 2000–2013 as the study case, we investigated the regional differences in socio-economic driving forces on both the estimated water footprint (WF) in crop production and relative inter-city VW flows for each crop per year. Results show that although there is little change in total WFs in crop production (∼43.3 billion m3/y on annual average), the WF per unit mass of crop decreased and the crop structure in the total WFs changed greatly. The BTH region was a VW importer with net VW import of 11.7 billion m3/y by 2013 but the roles of each cities were different. Inter-city VW was predominantly exported from the southern regions. The per capita GDP was the main positive driver of both total WFs and relative VW flows. Whereas economic productivity and consumption capacity were inhibiting factors for the WFs and VW flows, respectively. The levels of total crop WFs in agricultural cities were more sensitive to the effects of the main driving factors. The intensity of driving factors behind the inter-regional crop-related VW flows was shown to be directly related to regional role as an importer or exporter. Aiming for a balance between water sustainability, food security and economic developments, the current analysis suggests characteristic-based agriculture in terms of regional differences in water consumption and local roles in relative inter-regional VW flows. Especially for agricultural cities which are VW exporters, reducing water consumption per unit agricultural product and increasing economic production value per drop of water used in all sectors are equally important.