Abstract
This study aims to evaluate the impact of international trade on global water supply-demand balance, focusing on irrigation water requirements derived from food consumption. In this study, the water supply-demand balance is estimated by using the water stress index. The concept of a water footprint is applied to evaluate indirect water consumption caused by importing food, along with direct water consumption derived from domestic food production. Irrigation efficiency is used to convert water consumption into water withdrawal. The amount of available water resources is defined as a restriction on the maximum water availability for agriculture, which does not mean all the renewable water resources used in the agricultural sector. In 2010, 41 countries were found to be under high or moderate water stress, those are equivalent to 30% (1.9 billion) and 28% (1.8 billion) of the world population, respectively. In addition, water stress of the 8 countries in these 41 countries should be caused by food exportation. For example, in Thailand, water stress should be caused by exporting rice, which is accounted for 86% (26.7 km3) of its irrigation water withdrawal originated from food production for export.
