A systematic literature review on groundwater recharge dynamics under climate variability, land use change and sea level rise

Abstract Groundwater recharge is critically impacted by climate change, land-use changes, and sea-level rise, posing a major threat to global water security. This study conducted a systematic literature review to synthesize the impacts of these pressures on groundwater recharge, with a focus on vulnerable coastal regions. Following the PRISMA protocol, we analysed 63 relevant studies from five databases (GeoRef, Google Scholar, ScienceDirect, Scopus, Web of Science) published between 2014 and 2024. The major findings reveal that: (1) groundwater recharge is undergoing a significant consistent decline, averaging 14.6 ± 5.6 mm per year, primarily driven by urban expansion and rising agricultural water demand (up to 80%); (2) increased rainfall variability and hydroclimatic extremes are projected to reduce recharge by up to 60% by 2100; and (3) sea-level rise exacerbates saltwater intrusion, diminishing freshwater availability in coastal aquifers. This review highlights the urgent need for adaptive management strategies but also identifies critical research gaps. Future studies should prioritize: (1) the development of integrated models that capture the complex feedback between all three stressors (climate, land use, and sea-level rise), rather than treating them in isolation; and (2) enhanced field-based monitoring and palaeohydrological investigations to ground-truth model projections and reduce uncertainty in recharge estimates, particularly in data-scarce regions.