Background Atmospheric CO ₂ Regulates the Local and Non‐Local Climate Impacts of Amazon Deforestation

Amazon deforestation has substantial impacts on the local and regional climate system, yet the extent to which future atmospheric CO 2 trajectories modulate these impacts remains unclear. Here, we assess the climatic impacts of Amazon deforestation under contrasting atmospheric CO 2 scenarios using the Community Earth System Model version 2 (CESM2). Experiments were conducted with two land cover scenarios (a control and a business‐as‐usual Amazon deforestation scenario) combined with high and low CO 2 emission pathways for the period 2050–2080. Results show that high CO 2 conditions amplify both local and non‐local biogeophysical effects of Amazon deforestation. Under high CO 2 conditions, deforestation exacerbates warming within deforested regions while also modifying low‐level circulation and moisture transport across South America, leading to aridification in non‐deforested regions such as eastern Brazil. These remote effects weaken terrestrial carbon uptake and potentially increase the risk of forest degradation. Our findings highlight that future Amazon deforestation may trigger more severe climatic consequences without CO 2 mitigation.