The Growing Role of Evaporative Demand in Driving Record‐Breaking Droughts in the Amazon Basin

Abstract Amazon droughts have historically been driven by precipitation deficits, but recent escalating drought events highlight a regime shift toward “hot droughts.” By decomposing historical drought drivers (1979–2024), we show that rising evaporative demand (represented by potential evapotranspiration, PET) now acts as a primary driver of drought intensification. While rainfall deficits remain the dominant contributor to the record‐breaking 2024 drought, escalating atmospheric thirst almost doubled its severity. Rising PET also expands the total drought footprint, disproportionately amplifying exceptional (D4) droughts and nearly tripling their affected area in 2024 compared to precipitation deficits alone. This PET increase is forced comparably by background warming and increased shortwave radiation; neutralizing either factor during 2024 reduces D4 drought coverage by 25%–33%. Linked to observationally confirmed declines in dry‐season cloud cover, these compounding thermodynamic and radiative feedbacks are driving a shift toward increasingly extreme hot droughts across the Amazon.