Abstract
Tropical forests are vital to biodiversity and the global carbon sink but are increasingly vulnerable to climate change. This study assesses the causal effects of climate anomalies on tropical forests' tree growth across the tropics, focusing on temperature (TEMPan), evaporative demand (VPDan), solar radiation (SRADan), and water deficit (MCWDan). We use a causal inference framework and Bayesian multilevel models with data from 89 permanent plots across South America, Africa, Southeast Asia, and Oceania. Results show that increasing TEMPan, MCWDan, and SRADan negatively impact tree growth, with TEMPan effects primarily mediated by VPD. Growth decline is more pronounced in warmer tropical forests, with no clear biogeographic differences. These findings suggest that the productivity of warm moist tropical forests may be threatened by climate change and underscore the need to study the interplay between anomalies and historical climates while using causal inference frameworks to avoid spurious associations.