Excessive extraction of groundwater for irrigation in regions of slow renewal is the main cause for global groundwater depletion, concludes an overview article published online this week in Nature Geoscience. To make food production sustainable, groundwater levels in these regions must be stabilized.

Werner Aeschbach-Hertig and Tom Gleeson synthesize work on the use and depletion of groundwater. They argue that groundwater depletion is a global problem in its impacts on sea-level rise and agricultural production, but that it can only be tackled at the scale of individual river basins. They conclude that technical solutions to excessive extraction, such as efficient irrigation and water diversion, have failed to close the gap between extraction and recharge in some regions. They suggest that any solutions must instead include tailored considerations of how we value and manage groundwater in each region.