Abstract: Tropical forests, critical for global carbon storage and biodiversity, are failing to adapt at the pace required by accelerating climate change. A comprehensive study by Aguirre-Gutiérrez et al. (Science 387:eadi5414, 2025) analyzing four decades of data from 415 forest plots and 250,000 trees across the Americas reveals significant mismatches between functional trait shifts (e.g., leaf area, wood density, photosynthetic capacity) and climatic pressures. Survivor trees tracked climatic changes at less than 8% of the necessary rate, while recruits achieved only 22%, leaving ecosystems increasingly vulnerable. Lowland forests exhibited stronger trait responses compared to nutrient-limited montane forests, but neither aligned with future climate projections. By 2100, projected temperature rises (~ 4 °C) and precipitation declines (~ 20%) may push forests into “no-analog” climates, surpassing adaptive thresholds. These lags threaten carbon sequestration, biodiversity, and ecosystem stability, underscoring the urgent need for emissions reduction, conservation of climate refugia, and assisted migration strategies to mitigate irreversible biome transitions.

Key words: Climate change adaptation, Tropical forests, Functional traits, Ecosystem resilience, Carbon sequestration