Inequality or injustice in water use for food?

The global distributions of water availability and population density are uneven and therefore inequality exists in human access to freshwater resources. Is this inequality unjust or only regrettable? To examine this question we formulated and evaluated elementary principles of water ethics relative to human rights for water, and the need for global trade to improve societal access to water by transferring 'virtual water' embedded in plant and animal commodities. We defined human welfare benchmarks and evaluated patterns of water use with and without trade over a 25-year period to identify the influence of trade and inequality on equitability of water use. We found that trade improves mean water use and wellbeing, relative to human welfare benchmarks, suggesting that inequality is regrettable but not necessarily unjust. However, trade has not significantly contributed to redressing inequality. Hence, directed trade decisions can improve future conditions of water and food scarcity through reduced inequality.