Land Surface Feedbacks Regulate Atmospheric Water Demand and Maintain Global Drying Stability

Abstract

Atmospheric aridity is widely projected to intensify under climate warming, driven by rapidly increasing atmospheric water demand, as reflected in potential evaporation (PE). Yet global trends in precipitation, runoff, and vegetation productivity reveal a contrasting pattern of enhanced water fluxes and widespread greening, known as the “aridity paradox.” Here we show that this apparent contradiction stems from a conceptual flaw in conventional PE formulations under a changing climate, which treat vapor pressure deficit (VPD) as an external driver, despite its strong regulation by land–atmosphere coupling. We address this issue by revising the PE equation that embeds VPD as a dynamic feedback, thereby restoring the physical coupling between energy and moisture fluxes. This new formulation projects significantly weaker increases in PE and better matches observed hydroecological trends, indicating that global aridity remains relatively stable in a warmer world. Our work establishes a conceptual basis for resolving the aridity paradox and calls for a systematic reevaluation of PE‐based indices in climate change projections and drought risk assessments.