Food security in a water-scarce world:making virtual water compatible with crop water use and food trade

Virtual water has been proposed as a mechanism with potential to reduce the effects of water scarcity on food security. To evaluate the role of virtual water in reducing the effect of water scarcity on food security, all components of the available water resource in agricultural areas must be quantified to provide a basis for evaluating food imports driven by water scarcity. We refer to this situation as ‘agri-compatible connections’ among water scarcity, virtual water, and food security. To date, this has not been captured in the literature on water scarcity, virtual water flows and food security. The lack of agri-compatibility has rendered the virtual water concept seemingly inconsistent with trade theories and water-food security policy needs. We propose two requirements for achieving agri-compatible connections: (i) the limit of crop production imposed by water scarcity should be captured by quantifying all components of the water available to satisfy specific crop water requirement in the importing economy, and (ii) food import should satisfy ‘water-dependent food security’ need, which is the actual or potential food security gap created by insufficient available water from all sources for crop production (all other things being equal). Further, we propose that agri-compatible water scarcity should capture three key elements: (i) a reflection of aridity or drought potential, (ii) quantification of all the components of water resource available to a given crop at a given locality and time, and (iii) use of crop- and catchment-specific water scarcity factors to evaluate the effect of crop production and virtual water on water scarcity. In this paper, we show the conceptual outlines for the proposed agri-compatible connections. Achieving agri-compatible connections among water scarcity, virtual water and food security will enhance the analysis and understanding of the role of virtual water for food security in the importing economy and water scarcity in the exporting economy. We suggest that achieving agri-compatibility will improve the use of virtual water as a mechanism to reduce existing and future pressures on global food security