What is a super El Niño and how does it affect global weather?

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1. 1

   Strong and moderate nonlinear El Niño regimes

   Climate Dynamics (Takahashi & Dewitte)Published Jun 1, 2015Checked Oct 13, 2026

   “The temporal evolution of various indices during the observed strong EN agrees very well with the events in CM2.1, providing further validation of this model as a proxy for nature. The two regimes differ strongly in the magnitude of the eastern Pacific warming but not much in the central Pacific. Observations and model agree in the existence of a finite positive threshold in the SST anomaly above which the zonal wind response to warming is strongly enhanced. Such nonlinearity in the Bjerknes feedback, which increases the growth rate of EN events if they reach sufficiently large amplitude, is very likely the essential mechanism that gives rise to the existence of the two EN regimes. Oceanic nonlinear advection does not appear essential for the onset of strong EN. The threshold nonlinearity could make the EN regimes very sensitive to stochastic forcing. Observations and model agree that the westerly wind stress anomaly in the central equatorial Pacific in late boreal summer has a substantial role determining the EN regime in the following winter and it is suggested that a stochastic component at this time was key for the development of the strong EN towards the end of 1982.”

2. 2

   Joint Boost to Super El Niño from the Indian and Atlantic Oceans

   Journal of Climate (Wang & Wang)Published Mar 18, 2021Checked Oct 13, 2026

   “Early onset endows super El Niño with adequate strength in summer to excite wind-driven responses over the Indian and Atlantic Oceans, which further facilitate IAB formation by coupling with the seasonal cycle. In return, IAB alternately produces additional zonal winds U over the Pacific Ocean, augmenting super El Niño via the Bjerknes feedback. Adding AN and IOD indices into the regression model of U leads to a better performance than the single Niño-3.4 model, with a rise in the total explained variances by 10%–20% and a reduction in the misestimations of super El Niños by 50%. Extended analyses using Coupled Model Intercomparison Project models further confirm the sufficiency and necessity of early onset and IAB on super El Niño formation. Approximately 70% of super El Niños are early-onset types accompanied by IAB and 60% of early-onset El Niños with IAB finally grow into extreme events. These results highlight the super El Niño as an outcome of pantropical interactions, so including both the Indian and Atlantic Oceans and their teleconnections with the Pacific Ocean will greatly improve super El Niño prediction.”

3. 3

   Super El Niño events drive climate regime shifts with enhanced risks under global warming.

   Nature communications (Xue et al.)Published Dec 12, 2025Checked Oct 13, 2026

   “Climate regime shifts (CRSs), characterized by abrupt and persistent transitions between alternative stable states in the climate system, pose serious threats to ecosystems and human well-being. Understanding the potential drivers of CRSs is crucial, particularly in a warming world where CRSs are becoming more frequent. Here, using multiple observations and model simulations, we find that the likelihood of CRS occurrence significantly increases in the context of super El Niño events due to their remarkable climate perturbations. This higher probability is detected across various climate elements, such as surface air temperature, sea surface temperature, and surface soil moisture. In addition, we suggest that this boost effect of super El Niño events on CRSs will be greatly amplified under future greenhouse warming. Our findings underscore a deeper and more persistent climate footprint of super El Niño events, suggesting that early warnings and proactive measures are crucial for mitigating their escalating risks.”

4. 4

   Strong sub-seasonal wintertime cooling over East Asia and Northern Europe associated with super El Niño events

   Scientific Reports (Geng et al.)Published Jun 13, 2017Checked Oct 13, 2026

   “We find that this large-scale cold spell can be attributed to the concurrent super El Niño event in the tropical Pacific. Our analysis reveals that all super El Niño winters (1982/83, 1997/98, and 2015/16) were accompanied by a rapid sub-seasonal North Atlantic Oscillation (NAO)/Arctic Oscillation (AO) phase reversal from a positive to a negative state during early January, which was largely caused by the interaction of these super El Niño events with the subtropical jet annual cycle. The NAO/AO phase transition leads to a rapidly strengthened Siberian High, which favors southward intrusions of cold air to East Asia and thus causes severe local cooling. Similar cold spells can also be detected over Northern Europe associated with the fast sub-seasonal NAO/AO phase reversal. Due to the weaker amplitude of the ENSO forcing, these sub-seasonal atmospheric responses cannot be detected for moderate El Niño events. The super El Niño associated sub-seasonal signal of the East Asian and Northern Europe wintertime temperature responses carries important implications for future predictability of regional extreme events.”

5. 5

   Super El Niño can raise coastal extreme sea-level risk tenfold

   Research paper (Monahan et al.)Published Sep 30, 2026Checked Oct 13, 2026

   “However, its effect on global coastal sea-level extremes remains poorly quantified, especially for very strong ("super") El Niños, which are rare. Here we analyse global reanalyses, hindcasts, and reconstructions to quantify how El Niño alters extreme sea level frequencies through mean sea level, tide, surge, and wave processes with distinct geographic fingerprints. We find low-frequency mean sea-level anomalies are the primary source of increased risk in the tropical Pacific during El Niño events, but that wave, tide, and surge play important secondary roles. Cross-basin thermocline tilt produces sea-surface height anomalies that correspond to an order-of-magnitude increase in exceedance risk along the tropical east Pacific, with the response steepening for strong events. The coincidence of the projected 2026–2027 Super El Niño with local maxima of long-period astronomical tidal cycles may produce 99th-percentile extremes in up to half of all high waters at some sites with potential major flooding and ecological impacts---the background shift alone is equivalent to 40–50 years of projected sea-level rise under SSP1-2.6.”

6. 6

   Coupling is key for the tropical Indian and Atlantic oceans to boost super El Niño.

   Science advances (Fan et al.)Published Sep 13, 2024Checked Oct 13, 2026

   “The influences of the tropical Indian and Atlantic oceans on the development of El Niño Southern Oscillation (ENSO), especially regarding super El Niño events, have been a subject of debate. In particular, several studies argue that these cross-basin influences may be mere statistical artifacts resulting from the high auto-correlation of ENSO. To clarify this issue, we conduct a series of perfect model hindcast experiments to untangle the individual and synergistic effects of the tropical Indian and Atlantic oceans. Our results clearly demonstrate that without these cross-basin effects, the Pacific warming would rarely reach super El Niño level. Specifically, the individual effect of the Indian Ocean efficiently enhances the development of super El Niño events. In contrast, the Atlantic's effect is initially limited because it fails to establish the Bjerknes feedback in the Pacific. However, when coupled with the Indian Ocean, the Atlantic's effect becomes more pronounced as it is amplified by the Bjerknes feedback established by the Indian Ocean.”

7. 7

   Predictive modeling of Super El Niño through integrated local and global climate signals

   Scientific Reports (Yoon et al.)Published May 12, 2025Checked Oct 13, 2026

   “This study introduces a novel predictive framework utilizing the Super El Niño Index (SEI), which integrates diverse datasets, including NOAA Sea Surface Temperature indices and regional data from Korea for correlation analysis and model development. Additionally, high-resolution simulations from NASA's ECCO2 project are utilized to visualize and quantitatively analyze ocean current and SST dynamics, providing a physical basis for understanding SE-induced variability. The SEI identifies SE events with a threshold value of 75 and demonstrates its effectiveness in accurately capturing major historical events, such as those in 1982-83, 1997-98, and 2015-16, while revealing a rising trend in SEI values since 1982, likely tied to global warming. The model successfully predicted an SEI of approximately 80 for 2023, later validated as one of the five most intense SE events on record. These findings highlight the far-reaching influence of SE events beyond the equatorial Pacific, extending to regions like Korea and Japan, and emphasize the necessity for robust predictive tools to mitigate the growing frequency and intensity of SE events in a warming world.”