The study examines the hydrologic changes in central-eastern Brazil, focusing on the role of anthropogenic forcing and natural factors. Speleothems from a well-ventilated cave in this region provide a high-resolution record of past climate conditions. The results show that the current aridity, characterized by a hydrological deficit, is unprecedented over the last 720 years. The drying trend is primarily driven by anthropogenic greenhouse gas emissions, leading to increased evapotranspiration and reduced precipitation. The study uses a detection and attribution approach to confirm that natural factors alone cannot explain the observed changes. The findings highlight the severe long-term drought in eastern South America, which is likely to be exacerbated by continued greenhouse gas emissions. The implications include increased agricultural losses, reduced hydropower production, and challenges for water supply systems. The research underscores the importance of accurate projections of future drought risk for policy formulation and adaptation strategies.The study examines the hydrologic changes in central-eastern Brazil, focusing on the role of anthropogenic forcing and natural factors. Speleothems from a well-ventilated cave in this region provide a high-resolution record of past climate conditions. The results show that the current aridity, characterized by a hydrological deficit, is unprecedented over the last 720 years. The drying trend is primarily driven by anthropogenic greenhouse gas emissions, leading to increased evapotranspiration and reduced precipitation. The study uses a detection and attribution approach to confirm that natural factors alone cannot explain the observed changes. The findings highlight the severe long-term drought in eastern South America, which is likely to be exacerbated by continued greenhouse gas emissions. The implications include increased agricultural losses, reduced hydropower production, and challenges for water supply systems. The research underscores the importance of accurate projections of future drought risk for policy formulation and adaptation strategies.