The article "Increasing frequency of extreme El Niño events due to greenhouse warming" by Cai et al. (2015) examines the impact of greenhouse warming on the frequency of extreme El Niño events. The study focuses on the eastern equatorial Pacific, where atmospheric convection and rainfall are key indicators of extreme El Niño events. These events are characterized by a pronounced eastward extension of the warm pool and atmospheric convective zone, leading to significant rainfall increases in the typically dry equatorial region. The 1997/98 and 1982/83 El Niño events, often referred to as "the climate event of the 20th century," caused severe global weather disruptions, including droughts, floods, and extreme weather events. The authors use climate models from the Coupled Model Intercomparison Project phases 3 and 5 (CMIP3 and CMIP5) to estimate the change in the frequency of extreme El Niño events. They find that greenhouse warming will lead to a doubling of the occurrence of extreme El Niño events in the future. This increase is attributed to a faster warming rate along the equatorial Pacific compared to off-equatorial regions, particularly in the eastern equatorial Pacific. The study also highlights the importance of the diminishing or reversing meridional sea surface temperature (SST) gradient in the eastern equatorial Pacific, which facilitates the development of atmospheric convection and the associated rainfall anomalies. The results are robust across a subset of coupled general circulation models (CGCMs) that accurately simulate the nonlinear ocean-atmosphere coupling observed in extreme El Niño events. The findings suggest that greenhouse warming will likely result in more frequent and severe extreme El Niño events, with significant socio-economic implications.The article "Increasing frequency of extreme El Niño events due to greenhouse warming" by Cai et al. (2015) examines the impact of greenhouse warming on the frequency of extreme El Niño events. The study focuses on the eastern equatorial Pacific, where atmospheric convection and rainfall are key indicators of extreme El Niño events. These events are characterized by a pronounced eastward extension of the warm pool and atmospheric convective zone, leading to significant rainfall increases in the typically dry equatorial region. The 1997/98 and 1982/83 El Niño events, often referred to as "the climate event of the 20th century," caused severe global weather disruptions, including droughts, floods, and extreme weather events. The authors use climate models from the Coupled Model Intercomparison Project phases 3 and 5 (CMIP3 and CMIP5) to estimate the change in the frequency of extreme El Niño events. They find that greenhouse warming will lead to a doubling of the occurrence of extreme El Niño events in the future. This increase is attributed to a faster warming rate along the equatorial Pacific compared to off-equatorial regions, particularly in the eastern equatorial Pacific. The study also highlights the importance of the diminishing or reversing meridional sea surface temperature (SST) gradient in the eastern equatorial Pacific, which facilitates the development of atmospheric convection and the associated rainfall anomalies. The results are robust across a subset of coupled general circulation models (CGCMs) that accurately simulate the nonlinear ocean-atmosphere coupling observed in extreme El Niño events. The findings suggest that greenhouse warming will likely result in more frequent and severe extreme El Niño events, with significant socio-economic implications.