Global groundwater sustainability: A critical review of strategies and future pathways

Groundwater is essential for sustaining life on Earth, yet it faces critical threats from unsustainable exploitation. Here, we conducted a critical analysis of 386 peer-reviewed sources to examine commonly introduced conservation measures, their feasibility, and potential implications, along with an additional assessment to explore spatial opportunities for sustainable groundwater management. A meta-analysis was also performed to investigate the major driving factors contributing to rebound effects – where increased resource efficiency let to converse effect regarding resource use – and the failures of adopted measures. Delving into the specifics of groundwater governance in the five top-consuming countries, we further identified reinforcing policies to address groundwater overexploitation and proposed necessary revisions to promote sustainability. According to the results, the effectiveness of efforts to improve groundwater productivity significantly depended on water and land scarcity, as well as strict regulatory policies, and didn’t always result in groundwater savings. Rebound effects were more likely under supply-side solutions, with potential overexploitation increases of up to 52% in 50% of cases. Although demand-side solutions reduced overexploitation rates to as low as 3%, they were still ineffective in 69% of cases for aquifer recovery in the absence of strict regulatory policies. In general, groundwater stabilization was achieved in less than 30% of the case studies, mostly when multiple measures were implemented, highlighting that no single solution category can sustainably control aquifer depletion. Addressing economic water scarcity and closing yield gaps had the potential to save groundwater and enhance food security in 25% and 75% of the world, respectively. According to the policy series in top major groundwater-consuming countries, the late initiation of recovery processes, significant conflicts between groundwater protection and national socioeconomic and political policies, predominant state-centered governance, lack of a nexus approach and integrated water management, the oversight of groundwater’s global significance, institutional corruption, and insufficient government commitment to aquifer recovery were among the most common factors reinforcing unsustainable groundwater management.