What is the super El Niño and why is it coming?
By Avesta Afshari-Mehr
Every few years, the tropical Pacific Ocean experiences an extraordinary phenomenon: vast belts of trade winds that normally push warm surface water westward weaken, and that heat spills back east toward South America; sea surface temperatures rise dramatically, and the whole world feels it. This phenomenon is called ‘El Niño.’
El Niño (quite literally ‘The Boy’) is part of a natural climate cycle called the ‘El Niño-Southern Oscillation’ (ESNO). Under normal conditions, trade winds blow westward across the equatorial Pacific, piling warm water around Indonesia and Australia. When those winds falter, the warm water spreads eastward instead. An El Niño begins when Pacific surface temperatures rise 0.5°C above the long-term average. A particularly powerful event, a ‘super’ El Niño, pushes that anomaly past 2°C, and the consequences compound rapidly.
There is a colder counterpart, ‘La Niña,’ which cools the eastern Pacific rather than warms it. We’ve seen that just recently with the considerably colder recent winter here in the UK.
The World Meteorological Organisation (WMO) recently reported that sea surface temperatures in the equatorial Pacific are rising rapidly, pointing to a likely return of El Niño conditions as early as May–July 2026. “After a period of neutral conditions at the start of the year, climate models are now strongly aligned, and there is high confidence in the onset of El Niño, followed by further intensification in the months that follow,” says Wilfran Moufouma Okia, Chief of Climate Prediction at the WMO.
What makes this moment particularly alarming to climate scientists is the baseline we’re starting from
A surge of warm water known as a Kelvin wave has been pushing heat to the surface ahead of earlier projections. NOAA’s Climate Prediction Centre puts the probability of El Niño emerging between June and August 2026 at 62%, persisting through at least the end of the year, and gives a one-in-three chance that it would be ‘strong’ by October-December 2026.
But what makes this moment particularly alarming to climate scientists is the baseline we’re starting from. Global average temperatures have already risen to 1.4°C above pre-industrial levels, and a super El Niño could raise temperatures by a further 0.2°C. Because the planet has warmed since the last major cycle, any new heat from the Pacific is added to a higher total, making the final temperatures more extreme. It is clear that, the bigger the phenomenon, the more detrimental its impacts on weather across the planet.
Fortunately for us, Britain doesn’t sit in El Niño’s direct path: the most immediate effects hit Australia, Indonesia and parts of South America. But that doesn’t mean the UK is completely insulated from the effects. The UK experiences what climatologists call teleconnections – indirect effects driven by changes in the North Atlantic jet stream, which El Niño pushes or pulls into unusual configurations. Those configurations dictate whether Britain gets mild Atlantic westerlies, bitter Arctic air, or relentless storms. The pattern differs by season. During summer under El Niño, the UK and northern Europe generally experience drier and warmer conditions as the jet stream shifts northward, suppressing rainfall. Sounds appealing… but the picture for winter is considerably more complicated as a result.
A moderate El Niño increases the likelihood of polar vortex disruption, which can lead to higher risks of cold and wintry conditions across western Europe. However, a ‘super’ El Niño tends to enhance the jet stream above the North Atlantic. A stronger jet stream acts as a conveyor belt for Atlantic storm systems; and in 2015-16, during a strong El Niño, the UK experienced what was then its warmest and wettest December on record, culminating in Storm Desmond, which dropped over 340mm of rain on parts of Cumbria within 24 hours.
El Niño is among natural phenomena which have been reshaping global weather for millennia. But the world it arrives into in 2026 is fundamentally different from previous cycles. Climate change has raised the floor, and El Niño the ceiling. The UK’s Committee on Climate Change identifies heat, flooding and drought as the three biggest climate risks facing the country – a super El Niño has the potential to intensify all three.
Image: David Dixon via Wikimedia Commons
