Two decades of human- and climate-induced groundwater storage shifts in Brazil

Abstract Brazil holds the world’s largest reserves of renewable freshwater—the country contributes ~ 20% of the planet’s inland water discharge into the oceans 1 —, yet recurrent water crises expose its growing vulnerability under extreme events 2 . While surface water dominates national supply, vast groundwater reserves remain underused and poorly monitored, representing a critical but untapped resource for climate resilience and national security. Here, we present a data-driven spatiotemporal reconstruction of Brazil’s groundwater behavior over the past two decades, integrating multi-satellite and in situ data into an artificial intelligence modeling framework. Results reveal groundwater variability, recharge, and trends under climatological and anthropogenic stressors across the nation’s ~ 8.5 million km² of land. Brazil’s 2002–2023 averaged aquifer recharge is 223 mm—12% of annual precipitation—totaling ~ 1,900 km 3 of annual renewable groundwater volume. Persistent depletion or no recharge is observed in heavily exploited aquifers in eastern Brazil, further impacted by prolonged droughts 1,2 and climate oscillations. Such aquifers present depletion trends mirroring patterns observed in intensively exploited aquifers in Bangladesh 3 , India 4 , Iran 5 and the U.S. 6,7 . As a world’s major breadbasket, Brazil plays a vital role in global food security. Results presented here are therefore critical to the nation’s sustaining agricultural productivity under increasing climate stress.