Should we be worried about El Niño? The phenomenon is a naturally occurring part of what is known as the ENSO cycle (the El Niño Southern Oscillation) and happens every two to seven years. The US National Oceanic and Atmospheric Administration (NOAA) and other scientific agencies declare an official El Niño event once Pacific Ocean temperatures are 0.5 degrees higher than normal, alongside weakening trade winds. While it usually brings changes to rainfall patterns across the tropics, leading to droughts and flooding – sometimes catastrophically so – the 2026-2027 El Niño is taking place on a planet that is already over 1 degree hotter due to human-caused global warming.
With a temperature anomaly of 2 degrees already in parts of the eastern Pacific by July 2026, this year’s El Niño looks on track to have no precedent in living memory. But while the ENSO cycle is natural, it is being turbocharged by global heating, in particular ocean warming. A team of scientists led by Columbia University’s James Hansen published an analysis last week that claimed the abnormal “Super-Duper El Niño” strength is “likely human-driven”.
As far back as 2014 a study published in Nature Climate Change reported that the frequency of extreme El Niño events would double in response to global heating. A research article published in Science last week found that El Niño events over the past 40 years have grown roughly 40 per cent stronger than those seen during the pre-industrial era, in parallel with global temperatures. This would suggest that as the planet heats up we can expect more extreme El Niños.
The 2015 “very strong” El Niño saw temperature anomalies well above 2 degrees at its peak. It brought catastrophic forest and peat fires in Indonesia, extensive coral bleaching and more tropical cyclones. There were crop failures in Southern Africa with up to 10 million people in Ethiopia requiring emergency food aid, and drought and fire risk in Australia.
READ MORE
‘We rechristened our kitchen the Law Library’: Negligence claim had toll on vindicated surgeon
Man (21) jailed for murder of father of five in Cork golf-club attack
New Government investment scheme: Here’s what we know – and don’t know
Electric Picnic 2026: In pictures
But this year’s El Niño could exceed the 2015 event “by a mind-blowing margin”, predicts one climate scientist, Zeke Hausfather.
NOAA does not even have an additional category name for an El Nino of above 3 degrees.
El Niños mostly impact the tropics but this does not mean that Europe will not be affected. The phenomenon, while temporary, can affect rainfall patterns on the European Continent and drive global temperatures up even further, leading to more weather extremes and heat stress. And this summer’s European heatwaves have shown just how dangerous heat can be. A study published by The Lancet in August 2026 estimates that each degree Celsius of global warming adds a month of intolerable heat for one billion people, many of whom cannot afford air conditioning or cooling.
For Ireland and the UK a “super” El Niño (defined as an ocean temperature anomaly of 2 degrees) could be associated with increased rainfall and more storms, driven by a southerly shift in the jet stream. There is limited information on the Met Éireann website about what this year’s monster event (which has a 95 per cent likelihood of exceeding 2 degrees) might mean for Ireland.
[ El Niño could cause Ireland to have unseasonably warm autumnOpens in new window ]
It says only that “the currently developing strong El Niño has the potential, together with the underlying global warming trend, to lead to record high global mean temperatures in the second half of 2026 and in 2027, and to extreme weather events. [But] its influence on Ireland and Europe is comparatively weak, highly variable, and not robust in the present-day climate”.
Climate science is not the same as weather forecasting. Scientists are careful to “stay in their lanes” and only report conclusions they have confidence in. But the public, along with Government agencies and local authorities, needs more than a 10-day forecast when we know this winter is likely to see the strongest El Niño in recorded history.
Ireland has a thriving scientific research community, yet there is too little public discussion of the fact that the rate of global heating is accelerating, not stabilising or declining. The Earth’s Energy Imbalance (EEI) has doubled in the last 15 years. The last time the Earth had this much carbon dioxide in the atmosphere, temperatures were 2.5-4 degrees warmer than the pre-industrial average, and sea levels were 15m-25m higher than today’s levels. Those conditions developed over thousands of years, however; not 200 years. There is simply no precedent for the pace of global heating that is taking place now, and it is greater than many model estimates in the most recent assessment report of the IPCC. If this information is not keeping our political leaders awake at night, it should be.
Eight years ago, scientists from the Stockholm Resilience Centre warned that a failure to curb greenhouse gas emissions along with the continued degradation of the biosphere could tip the Earth out of the stable climatic conditions to which human civilisation has adapted, and into a new unstable and “hothouse” state. Such a process could unfold slowly or, like bankruptcy, could then happen very quickly if key thresholds or tipping points are crossed.
All of this means that on a planet already heating up due to the build-up of greenhouse gases in the atmosphere, the 2026 El Niño will throw fuel on to a raging fire.
Sadhbh O’Neill is a climate and environmental researcher