ENSO atmospheric feedbacks under global warming and their relation to mean-state changes

Abstract Two atmospheric feedbacks play an important role in the dynamics of El Niño/Southern Oscillation (ENSO), namely amplifying zonal wind feedback and damping heat flux feedback. Here we investigate how why both change under global warming climate models participating 5th 6th phase Coupled Model Intercomparison Project (CMIP5 CMIP6) business-as-usual scenario (RCP8.5 SSP5-8.5, respectively). The over western equatorial Pacific (WEP) becomes significantly stronger two third models, on average by 12 ± 7% these models. eastern central (EEP CEP, respectively) increases as well nearly all with effect increasing 18 11%. simultaneous strengthening can be explained EEP relative to WEP off-equatorial regions, which shifts rising branch Walker Circulation east mean convection CEP. This turn leads a vertical response during ENSO events CEP that strengthens feedbacks. We separate into sub-ensembles STRONG WEAK feedbacks, 2/3 underestimate present-day conditions more than 40%, causing error compensation dynamics. biased state 20C constrains projection 21C, sub-ensemble also have weaker 21C. Further, due realistic teleconnections, postulate one should confidence predictions belonging sub-ensemble. Finally, analyze relation between amplitude change. find simulating eastward shift precipitation Eastern Niño tend predict larger warming.