Analyzing the sensitivity of gross primary production to the water stress in the Amazon rainforest using CMIP6 models

Tropical rainforests in the Amazon play a vital role in absorbing atmospheric CO2, yet there remains a significant degree of uncertainty surrounding the process, magnitude, and potential future changes. In this study, we used outputs of Earth System Models (ESMs) to explore the impacts of dry-season precipitation changes on the terrestrial carbon cycle, with a specific focus on Gross Primary Production (GPP), which has yet to be thoroughly examined. The seasonal amplitude of GPP over the Amazon rainforests from the CMIP6 ensemble displayed significant variations among models resulting from dry-season decline, and these are much higher amplitude compared to reference data from 1981-2000. The regions with less precipitation are particularly vulnerable in the models, and this dry-season decline is anticipated to significantly intensify by the end of the 21st century due to the drying associated with global warming.