Abstract The Amazon's hydroclimate exhibits basin‐scale early‐warning signals of critical slowing down (CSD), a statistical signature of declining resilience as systems approach critical transitions. We apply a multi‐metric framework to precipitation, evapotranspiration, Soil moisture (SM), and extreme streamflows, tracking rolling variance, lag‐1 autocorrelation (AC1), distributional asymmetry and tail heaviness, entropy, and persistence parameters. Results reveal hydrologically and geographically coherent patterns: variance and AC1 increase, distributions become heavier‐tailed and more asymmetric, and entropy declines. Aggregating across metrics, resilience erosion is widespread: 71% of the basin exhibits at least three of five CSD signals in precipitation, 68% in evapotranspiration, and 62% in SM. For streamflow extremes, rising scale of fluctuation and Hurst exponent, combined with declining mean‐reversion rates, indicate slower recovery and longer persistence in extreme states. Two corridors concentrate risk: the southwestern Andean‐foreland arc (Juruá–Purus–Madeira) and the southeastern Brazilian‐Shield flank (Tapajós–Xingú), with flood peaks showing the strongest signals. The El Niño–Southern Oscillation (ENSO) itself displays CSD signatures and, often amplified by warm Tropical North Atlantic conditions, interacts nonlinearly with deforestation and fires, which also exhibit CSD‐like behavior, to dry and heat the land surface, fragment forests, and weaken moisture recycling. These compounding pressures culminated in the record 2023–2024 drought, which persisted well beyond the El Niño peak. Our findings reveal escalating risks to South America's water security, ecosystem integrity, and climate regulation, underscoring the urgent need to halt deforestation, control fires, and reduce greenhouse forcing to restore the Amazon's hydrological resilience.
Germán Poveda (Sun,) studied this question.