Irrigation worldwide is a major driver of the rising pressure on water resources. In particular, the use of nonrenewable groundwater in agriculture has tripled between 1960 and 2000. On a global average, 20% of current irrigation water is nonrenewable groundwater. Consequently, aquifer levels and groundwater reserves are quickly falling in many regions. Groundwater depletion is a major concern notably because groundwater can be an essential alternative water source during droughts, which are becoming more frequent under climate change. While water resources management is essentially a local issue, global trade strongly connects food-producing regions, using water resources, to remote locations where these commodities are consumed. A growing body of research is analyzing this connecting phenomenon, called virtual water trade (VWT)—the exchanges of products requiring water resources to be consumed for their production. VWT highlights that nations that are importing agricultural products often rely on their trade partners’ water resources. This dependence can be a risk to both producers and importers if agricultural water use is unsustainable. While recent efforts have been made to estimate this sustainability, a number of challenges remain, in particular evaluating the sustainability of groundwater use. This chapter examines the emergence of water sustainability aspects in recent VWT literature, highlights the recent advances and remaining issues in evaluating the water sustainability of agriculture globally, and makes recommendations for future scientific research and societal change: consider groundwater both at the local scale and at the global scale; improve our understanding of groundwater storage and dynamics with new models and data; and raise the profile of groundwater sustainability in governance frameworks to eventually end environmental damages of groundwater exploitation.
Global Groundwater, 2021, Pages 347-357,