Forced changes in El Niño–Southern Oscillation due to global warming and the associated uncertainties in ACCESS-ESM1.5 large ensembles

Understanding the forced response of El Niño–Southern Oscillation (ENSO) to future global warming (GW) is important for reliable climate projections; however, many aspects this are yet be fully understood. Here, we use two large ensembles CMIP6 historical and SSP3-7.0 experiments (each with 40 ensemble members), performed ACCESS-ESM1.5, investigate combined greenhouse gas (GHG) aerosol changes in selected ENSO properties. We document ENSO's amplitude, power spectrum, skewness, feedbacks quantify internal variability associated these changes. There a modest but statistically significant GW-induced increase ensemble-mean amplitude sizable variation (due variability) both increases (in 80% members) decreases. To understand mechanism variation, examine role mean state atmosphere-ocean coupling processes Pacific. find that change most sensitive zonal wind forcing change. A gradient sea surface temperatures (SSTs) also plays an change, atmospheric Bjerknes feedback thermocline playing minor role. The implications some caveats findings discussed.