Historical and Future Asymmetry of ENSO Teleconnections with Extremes

Abstract El Niño–Southern Oscillation (ENSO) is the dominant source of climate variability globally. Many of the most devastating impacts of ENSO are felt through extremes. Here, we present and describe a spatially complete global synthesis of extreme temperature and precipitation relationships with ENSO. We also investigate how these relationships evolve under a future warming scenario under high greenhouse gas emissions using 14 models from phase 6 of Coupled Model Intercomparison Project (CMIP6) ensemble. First, we demonstrate that models broadly capture observed ENSO teleconnections to mean and extreme climate using the Twentieth Century Reanalysis, version 3 (20CRv3). The models project that more regions will experience an amplification of the historical ENSO teleconnection with mean temperature and precipitation than a dampening under a high-emission climate scenario. The response of the ENSO teleconnection with extremes is very similar to the mean response, with even larger changes in some regions. Hence, regions that are predicted to experience an amplification of the ENSO teleconnection under future warming can also expect a comparable amplification in the intensity of extremes. Furthermore, models that suggest greater amplification of ENSO amplitude also tend to exhibit greater intensification of mean and extreme teleconnections. Future changes in regional climate variability may be better constrained if changes in ENSO itself are better understood.