New research published in Nature Communications demonstrates that super El Niño events—the most extreme forms of the El Niño-Southern Oscillation—dramatically increase the probability of climate regime shifts (CRS) and that this amplification will intensify under continued global warming. Using observational data spanning several decades and advanced climate model simulations, scientists have established a clear connection between these powerful tropical ocean-atmosphere events and abrupt, long-lasting changes in Earth’s climate patterns.

Climate regime shifts represent sudden, sustained transitions between different stable climate states, occurring at multiple timescales from glacial-interglacial cycles to decadal fluctuations. Unlike gradual warming trends, these shifts involve rapid reorganization of climate patterns and can be extremely difficult to reverse. The consequences are severe: ecosystems restructure, agriculture becomes disrupted, water availability changes, and weather patterns shift dramatically. While various triggers exist—including extreme weather events, volcanic activity, and solar variations—the El Niño-Southern Oscillation stands out as a particularly powerful driver because it reorganizes global atmospheric circulation and intensifies regional climate extremes worldwide.

Analysis of observational records revealed that baseline CRSs occur naturally across sea surface temperature (SST) in extratropical oceans, surface air temperature (SAT) over land regions, and soil moisture in central Asia, the Amazon, East Africa, and Australia. Notably, standard El Niño and La Niña events produce minimal increases in CRS likelihood, demonstrating that regular ENSO variability is insufficient to trigger widespread transitions.

In striking contrast, super El Niño events—which have occurred only three times in recent decades (1982/83, 1997/98, and 2015/16)—generate substantial and coherent increases in regime shift probabilities across all three climate variables. The strongest SST shifts occur in ENSO-sensitive regions including the North Pacific, Indian Ocean, and Gulf of Mexico. Land-based SAT regime shifts intensify over East Africa, South America, and Maritime regions, while soil moisture shifts threaten agricultural areas in Australia and central Asia with prolonged drought.

Specific examples illustrate these mechanisms. Following the 1997/98 super El Niño, central North Pacific SST decreased by approximately 0.8°C, while the 2015/16 event triggered unprecedented temperatures and drought in the eastern Amazon. These shifts operate through physical processes like the “Reemergence” mechanism, where wintertime SST anomalies persist through subsurface ocean memory, and land-atmosphere coupling that amplifies heat retention. Testing with multiple datasets and varying analytical parameters confirmed these findings are robust and methodologically sound.

Because super El Niño events are rare, scientists employed the CESM2-LE large ensemble model to extend analysis across longer timeframes. Results show that super El Niño increases global CRS probabilities by approximately 20% for both SST and SAT, and 5–10% for soil moisture—substantially larger than regular ENSO impacts.

Critically, under future warming scenarios (SSP3–7.0), CRS frequencies increase markedly compared to the historical period, with amplification particularly pronounced for super El Niño events. Regular ENSO only modestly increases CRS probabilities in a warmer climate, whereas super El Niño generates much stronger and wider-ranging shifts. This intensification reflects projected strengthening of ENSO’s climatic impacts, shallower ocean mixed layers with reduced heat capacity, and enhanced land-atmosphere feedbacks that prolong soil moisture anomalies. One notable finding is that under warming, non-super El Niño years can trigger soil moisture shifts comparable to super El Niño events, indicating greater climate system sensitivity. CMIP6 models independently confirm these causal relationships.

The research demonstrates that super El Niño events can catalyze transitions in decadal climate patterns, potentially triggering Pacific Decadal Oscillation phase shifts—a pattern clearly evident when comparing observed PDO transitions in the late 1990s and 2016 with corresponding super El Niño events. Beyond atmospheric and oceanic variables, these extreme events may induce persistent or even irreversible changes in sea ice dynamics and ecosystems, with potential consequences for Arctic and Antarctic regions. Super El Niño could amplify sea ice loss through positive feedback mechanisms, theoretically triggering catastrophic ice shelf disintegration and accelerating sea-level rise.

A critical uncertainty remains: distinguishing whether super El Niño-triggered climate transitions will reverse naturally or cross irreversible thresholds—a distinction with profound implications for predictability and societal planning. Detailed regional and mechanism-specific investigations are essential.

Since CRSs profoundly affect ecosystems, livelihoods, and economies, and since global warming will amplify both super El Niño impacts and climate system sensitivity, CRS probabilities are projected to increase nonlinearly, escalating vulnerabilities across environmental and socioeconomic systems. These findings enable identification of high-risk regions and climate variables, providing essential guidance for developing early warning systems and targeted adaptation strategies to strengthen ecosystem and community resilience against abrupt climate transitions.

Xue, A., Geng, X., Jin, FF. et al. Super El Niño events drive climate regime shifts with enhanced risks under global warming. Nat Commun 16, 11262 (2025). https://doi.org/10.1038/s41467-025-66143-7