COVER ART: Global map of water scarcity at the basin level in 2007 (source: International Water Management Institute, 2007). Definitions and indicators: little or no water scarcity: abundant water resources relative to use, with less than 25% of water from rivers withdrawn for human purposes; physical water scarcity (water resources development is approaching or has exceeded sustainable limits): more than 75% of river flows are withdrawn for agriculture, industry, and domestic purposes (accounting for recycling of return flows); approaching physical water scarcity: more than 60% of river flows are withdrawn and these basins will experience physical water scarcity in the near future; economic water scarcity (human, institutional, and financial capital limit access to water even though water in nature is available locally to meet human demands): water resources are abundant relative to water use, with less than 25% of water from rivers withdrawn for human purposes, but malnutrition exists. For more information, see J. Anim. Sci. 95:2001–2018. doi:10.2527/jas.2017.1439