This document discusses food security and water scarcity challenges. It presents virtual water as a missing piece in ensuring food security. Virtual water refers to the volume of water used to produce food that is traded internationally. Major points: - Water scarcity and increasing food demands pose challenges for global food security. Agricultural water use is projected to increase significantly by 2050. - Options to improve food security through increasing water productivity and efficiency as well as breeding drought-tolerant crops are important but have limitations. - International food trade, or virtual water flows, can help offset localized water scarcity and food insecurity. Countries can import food from water-abundant regions to meet demands.