UN predicts 'supersized' El Nino coming - expert comment
03 September 2026
Scientists from the University of Reading provide expert comment following news that the United Nations World Meteorological Organization, the WMO, has issued an update on its prediction for a 'supersized' El Niño event in the months ahead into 2027.
Professor Liz Stephens, Professor in Climate Risks and Resilience, Department of Meteorology, University of Reading:
“The very latest forecasts from forecasting centres all around the world continue to grow in confidence that the end of this year will see an exceptional El Niño event.
“El Niño is already making its expected impact. The ongoing Indian monsoon season has seen less rainfall than normal, and satellite rainfall estimates show that parts of East Africa, Central America and SE Asia are experiencing record dry conditions during what should be their rainy seasons.
"El Niño impacts continue even once the event itself has peaked. The extra heat in the atmosphere is expected to lead to heatwaves across the Sahel in spring next year. A failed rainy season in Southern Africa or Central America may mean that communities have to wait until the next one a year later for their livelihoods to recover. And El Niño rains which fall in East Africa can take many months to travel to Lake Victoria and many months more to travel along the Nile river.
"El Niño events release a lot of heat from the ocean into the atmosphere, adding to the overall climate change direction of travel, so 2027 is set to be the warmest year on record.
"During the large El Niño event of 1997/1998 the associated flooding in Somalia killed over 2000 people. With a bigger El Niño event on the way, and global temperatures now 0.7°C higher and capable of holding even more moisture as a result of climate change, scientists are concerned that there is potential for even more severe flooding."
Professor Richard Allan, professor of climate science, University of Reading, said:
"Record El Niño warmth is growing rapidly in the east Pacific as part the oceans’ slow, natural dance which rearranges their vast stores of heat and disrupts global wind and rainfall patterns, unleashing unusually wet or dry conditions across different parts of the planet.
"Each El Niño conjures a different twist but based on past events it is usual for parched conditions to grip large parts of northern South America, southern Africa and Australia while some usually dry regions are more likely to experience deluges, such as south west Europe, the southern United States and East Africa.
"The colossal shifts in moisture are so large they can even be measured by satellite as an acceleration in sea level rise as water normally destined to fall as rain over continents never arrives and instead temporarily piles up in the ocean.
"The influence of El Niño on UK weather is usually difficult to detect and forecasts for months ahead are less than reliable but it is notable that there have been some unusually strong signals of possible storminess by November. What is more certain is that because El Niño disrupts weather patterns globally, the damage from heatwave, drought and deluge across the world will affect the UK through economic and humanitarian factors.
"The exact effects on drought and deluge also depend on the fickle nature of our weather but the warmer climate we experience today, due to our emissions of greenhouse gases, means that when and where these climate extremes occur, the impacts will be more severe as an ever warmer, thirstier atmosphere more rapidly bakes and saps water from one region while funnelling this stolen moisture into drenching storm systems elsewhere.
"It is only possible to prepare and adapt so much to mounting damage from weather extremes, melting ice and sea level rise in a warming world, that heighten during El Niño. The only sure-fire way of limiting this ongoing human caused climate change is to ramp up collaborative efforts to transition to a cleaner, more efficient society that removes the burden of greenhouse gas emissions and is considerate of the diversity of people and the natural world upon which we all ultimately depend."
Professor Steve Woolnough, professor of climate science, University of Reading, and co-chair of the S2S2D conference, said:
"It's worth noting that while the 'supersized' category comes from a quote by the UN secretary general, rather than being an official classification by the WMO directly, it is very clear that the forecasts are that this will be the largest El Nino event in living memory.
"El Nino events, measured by the anomalies in sea surface temperature in the central equatorial Pacific region, typically reach about 1-2 deg C above the average. We have had a few recent big events, notably in the winters of 1982-83, 1997-98 and 2015-16, which ranged from about 2-2.5degC at their peak. The forecasts for this latest event suggest the anomaly will be peaking at around 3.5 degC above wehaqt's expected. Whatever you call it, that is massively above anything anyone has ever seen or recorded.
"Because it's such a large event we have no precedent for what we might expect. Around the Pacific Ocean the impacts of El Nino events are felt quite directly and so big events tends to mean bigger impacts. Away from the Pacific the pathways by which El Nino effects the weather are more complex and stronger El Nino's don't necessarily mean bigger impacts e.g. over the UK.
"The impact of El Nino events on the UK is less direct than in regions around the Pacific, so it is less consistent from event to event. It tends to lead to wetter autumns and early winters, in the period from September to December in the UK, and increased chances of colder weather in the later half of winter and into early spring, around January to March.
"The response to large events like this one is less certain, because we have so few examples of them. The latest seasonal forecasts are suggesting an increased likelihood of a wet autumn and early winter.
"Longer-range weather and climate forecasts, looking say months to years ahead, often look at patterns in the earth's system like El Nino to help provide an idea of the climate risks that may be ahead. By complete coincidence there are 400 of the world's leading longer-range forecast scientists coming to Reading next week. This huge El Nino shows just how important their work is to help people plan for the risk of extreme events. We couldn't have picked a better time to have this global meeting.
"El Nino events occur naturally and it's difficult to say how much of the unprecedented nature of this can be attributed to climate change. We know however that climate change is having a major background influence on extreme weather events. For those regions which see an increased likelihood of hot extremes in El Nino, such as south-east Australia, climate change is likely to make the impacts of El Nino much more extreme."
Professor Andy Turner, professor in monsoon systems, Department of Meteorology, University of Reading, said:
"El Nino events typically happen between every 2-7 years and involve a warming of the central or eastern Pacific Ocean on the equator. This warming changes the location of rainy areas over the Pacific, which then alters the winds and causes other changes in rainfall and temperature, floods and droughts throughout the tropics.
"The current El Nino is already large at around 2 degrees C and is forecast to become much stronger, perhaps 3.5 C or even hotter, something that I've never seen in my lifetime and quite scary.
"The most famous impacts of El Nino tend to be in the monsoon regions of India and West Africa, which get less rainfall than normal, causing shortages of water and reduced crop yields, even damaging the economy. This year's Indian monsoon is currently more than 10% below normal, with less than a month to go.
"El Nino also excites waves in the atmosphere that reach beyond the tropics, with the potential to change weather in parts of Europe and North America. These impacts are less predictable than those in the tropics but include wetter conditions in late summer and autumn for the region around Spain and perhaps a colder winter in Scandinavia. It is difficult to say with certainty what it means for the UK.
"There isn't strong evidence to suggest El Nino will happen more often due to climate change, but even if its likelihood doesn't change, the impacts of El Nino around the world will worsen. The warmer atmosphere holds more moisture, so as El Nino occurs, the swings between wet and dry conditions will become more extreme.
"The other thing that El Nino does is release a lot of heat that has been stored in the upper ocean back into the atmosphere. We expect El Nino to last at least into the new year, and all this heat that will be released from this very strong event will likely lead to warmer global average temperatures in 2027.
"Many scientists around the world work on the problem of subseasonal-to-seasonal prediction, which includes making forecasts for El Nino and its impacts. University of Reading is hosting a major international conference on this subject next week."
Dr Akshay Deoras, Senior Research Scientist, National Centre for Atmospheric Science and Department of Meteorology, University of Reading, said:
"El Niño is growing rapidly, and there are still months of fuel left before it peaks this winter. We are seeing an exceptionally strong event develop, with effects that could ripple across the globe through the rest of 2026 and into 2027.
"A big El Niño is a powerful natural pulse of heat. Over the next several months, huge amounts of heat will be released into the atmosphere, driving global temperatures sharply higher and potentially towards record levels in 2027. That extra heat will fuel more extreme rainfall around the world. The timing of the current El Niño could hardly be worse. We are already living through rapid global warming, with countries struggling to stay within the Paris Agreement goals. Thus, this natural surge of heat is arriving on top of a planet that is already warming rapidly.
"El Niño is not a one-size-fits-all weather event. It can shift rainfall pattern around the world, bringing a greater risk of drought in regions such as Australia, South Asia, the Maritime Continent, and extreme rainfall in others such as Southern US. Those impacts can then ripple into agriculture, water supplies, energy and food prices. For the UK, El Niño does not translate into one simple weather outcome. It has no strong link to our annual average temperature or rainfall, but it can tilt the odds towards a wetter, windier and milder autumn, followed by a cooler, drier winter.
"El Niño’s impacts have already begun. Its fingerprints are showing in South Asia, where the crucial monsoon, one of the first major weather systems to respond to El Niño, is significantly weaker this year.
"A strong El Niño starts with warm water on the move in the equatorial Pacific Ocean. Normally, trade winds blow from east to west across the tropical Pacific, piling warm water up in the western Pacific around Indonesia. But in the northern hemisphere spring, those winds can be interrupted by strong bursts of winds from the west, pushing some of that warm water eastwards across the Pacific. This year, we have seen an unusually large number of such westerly wind bursts, helping shift huge amounts of warm water towards the central and eastern Pacific. When that warm water reaches the surface, it heats the ocean and changes the atmosphere above it. The ocean and atmosphere then reinforce each other, creating a feedback loop that allows El Niño to grow. This year, that engine has been running unusually hard.
"Whilst El Niño is a naturally occurring phenomenon rather than a product of climate change, there is some evidence suggesting that global warming is fuelling and intensifying these events when they arrive."
Loading additional items please wait....
mask