Hot Droughts Increase the Likelihood and Impacts of Abrupt Drought‐to‐Pluvial Transitions Worldwide

Abstract

Hot droughts are intensifying under anthropogenic warming, yet whether extreme heat systematically alters the triggering of abrupt drought‐to‐pluvial transitions and their downstream impacts remains poorly understood. Here, we identify global drought‐to‐pluvial abrupt transition (DPAT) events and isolate the influence of antecedent thermal conditions by comparing hot‐drought‐triggered DPATs (DH‐DPATs) with transitions preceded by droughts without concurrent heat. We find that hot drought related transitions display broader hotspots and substantially higher occurrence, with frequency increasing from 66.7% to 316.7% across the interquartile range and a higher conditional transition probability (global mean: 44.89% vs. 38.95%). They also transition faster, sustain longer post drought heavy rainfall, and produce stronger rainfall intensity. Mechanistically, although both event types are associated with enhanced moisture convergence, antecedent heat imposes an additional thermodynamic preconditioning characterized by deeper boundary layers and higher convective instability, making comparable moisture recovery more likely to trigger deep convection. These heat‐mediated transitions amplify ecosystem carbon losses, intensifying reductions in gross primary productivity and solar‐induced chlorophyll fluorescence by about 43.7% and 26.8%, respectively, with the strongest relative impacts in croplands. They also contribute to increasing population and managed‐land exposure. Under future warming, DPATs are projected to shift further toward hot‐drought‐dominated pathways, with increases in both the contribution and transition likelihood of DH‐DPATs. These results highlight a thermodynamic pathway through which hot droughts increase the likelihood and impacts of abrupt drought‐to‐pluvial transitions worldwide.