Strengthened influence of Atlantic Niño on ENSO in a warming climate

Atlantic Niño can influence ENSO by modulating the Pacific Walker circulation. This interbasin connection is dominated by central Atlantic Niño (CAN) events, which began to emerge around 2000. Our analysis of observational data and climate model simulations reveals that the influence of CAN on ENSO will strengthen in a warming climate due to an enhanced Pacific response. On one hand, increased variability of the eastern Pacific intertropical convergence zone leads to stronger subsidence anomalies induced by CAN; on the other hand, strengthened atmospheric variability over the North Indian Ocean enhances the region’s response to CAN-induced Kelvin waves, promoting easterly anomalies over the western tropical Pacific. These changes are further linked to the pronounced interhemispheric warming contrast projected by climate models. Our findings underscore the growing influence of Atlantic Niño on ENSO, with important implications for seasonal climate prediction and future climate change projections.