Key points:
- El Niño is a natural climate phenomenon, typically lasting 9-12 months, that has been linked to crop failures, more frequent wildfires and concurrent droughts, increased flood risk, disruptions to fisheries, elevated civil conflict and increased disease risk in various regions.
- Present forecasts predict a 61% chance of El Niño emerging over May-July 2026 and persisting until at least the end of the year. While there is still uncertainty as of April, some models are forecasting the possibility of a very strong El Niño.
- The frequency and severity of El Niño events increased in the latter part of the 20th century, and climate change is projected to further increase both, as well as making these events more difficult to predict
- El Niño involves complex interplay among various atmospheric phenomena, making its impacts difficult to predict. However, it is associated with some general weather trends around the world, including:
- Increased rainfall and flooding risk in East Africa, northern Mexico, the southern US, Peru and Ecuador
- Elevated fire risk in Indonesia, Australia and the Amazon
- Drought conditions in India, southern Africa, the Philippines, Indonesia, the Amazon and Australia
- Warm conditions in Canada and the northern US
- Increased likelihood of tropical storm activity in the Pacific, less in the Atlantic
- Countries and ecosystems are already experiencing impacts from climate change, such as heatwaves, droughts and floods, which El Niño is likely to make worse.
What is El Niño?
First described by Peruvian fishermen in the late 19th century as warm ocean waters around Christmas time that disrupt fishing conditions, El Niño is a natural climate phenomenon in which sea surface temperatures in the equatorial Pacific are warmer than average. Under normal (or neutral) atmospheric conditions, trade winds – the east-to-west winds that blow along the equator – transport warm water from South America to Asia, which is then replaced by cooler water from lower depths. This process, referred to as upwelling, brings nutrients to the surface water, creating fertile fishing grounds.
During an El Niño event, the trade winds weaken, causing warm water to accumulate in the Pacific Ocean. By contrast, when the trade winds are strong, the opposite happens and more warm water is transported to Asia – called a La Niña event. These two opposing processes – El Niño and La Niña – make up the El Niño-Southern Oscillation (ENSO) cycle.
In the past, ENSO events were described as Eastern-Pacific (EP) events because the Eastern Pacific was where the maximum warming was located. However, recent decades have seen an increase in the frequency of Central-Pacific (CP) events, particularly since 2000, where the maximum warming is located in the central equatorial Pacific.1CP El Niño events are also referred to as “El Niño Modoki” and “warm pool El Niño”. The characteristics and associated impacts of these two events differ.2EP ENSO has stronger El Niño events compared to La Niña events, whereas CP ENSO has stronger La Niña events compared to El Niño events. Projections suggest a five-fold increase in CP events under climate change.
In its April 2026 El Niño forecast, the National Oceanic and Atmospheric Administration (NOAA), states that El Niño is likely to emerge over May-July 2026 (61% chance) and persist until at least the end of the year. While, as of April, there is wide uncertainty as to how strong the El Niño event will be this year, many models indicate that a strong El Niño event is possible. Some scientists are warning that the 2026 El Niño could be very strong and potentially the strongest in 140 years.
Forecasts made in the Pacific Ocean during the Northern Hemisphere spring are typically associated with higher uncertainty than at other times of the year. Clearer insights can be made from May when ocean-atmosphere links are stronger, meaning that the strong events forecast by some models may be downgraded.
However, this year, it is possible that unusual tropical cyclone activity may increase the chance of a stronger event, if the right conditions for El Niño already exist. The presence of rare triple cyclones in the West Pacific Ocean in April could make it more likely to see a strong El Niño event this year, as the storms push warm water eastwards across the Pacific toward the zone where El Niño conditions are monitored.
Impacts of El Niño
Though the effects were originally thought to be localised to the coastal regions of Peru and Ecuador, it is now known that the impacts of El Niño, as well as its cooler counterpart La Niña, are global and have been linked to crop failures, increased wildfire risk, increased flood risk, heightened concurrent drought frequency, disruptions to fisheries, increased civil conflict and higher disease risk in various regions of the world. Recent research shows that El Niño events do not just cause short-term disruption but can slow improvements in mortality for years, reducing life expectancy and generating substantial long-term economic losses in high-income Pacific Rim countries, such as the US, Canada, Australia, Chile, Japan and South Korea.
El Niño and climate change
The occurrence of extreme El Niño and La Niña events has increased since the 1950s, and climate projections suggest the frequency of extreme ENSO events will increase in the future.3The IPCC AR6 WGI report states that “a robust increase in ENSO rainfall amplitude [used for defining extreme El Niños and La Niñas] is found particularly in SSP2‑4.5, SSP3‑7.0, and SSP5‑8.5… The changes in ENSO rainfall amplitude in the long-term future (2081–2100) relative to the recent past (1995–2014) are statistically significant at the 95% confidence [level]”. 4While climate models do not show consensus regarding changes in ENSO sea surface temperature variability, models that simulate extreme ENSO events do show large agreement. Some projections suggest a doubling of extreme El Niño events as global temperatures continue to rise.5The future period in the study included projections until 2090. CP El Niño events are expected to become more frequent with climate change, while EP events are projected to become more extreme.
During the second half of the 20th century, various changes to the behaviour of ENSO were observed, including:
- An increase in the occurrence of CP El Niño events
- Increased frequency of more extreme El Niño and La Niña events
- Increased variability of both CP and EP ENSO events
- Changes in the origin of both CP and EP ENSO events since the 1970s from the western Pacific to the central and eastern Pacific.
As ENSO is a naturally highly variable phenomenon, determining whether the characteristics of ENSO events since the 1950s are the result of human-caused global warming, or simply a reflection of this inherent variability, is not straightforward, partly because sea surface temperature records before 1950 are sparse and unreliable.6The IPCC AR6 WGI report states that “there is medium confidence that both ENSO amplitude and the frequency of high-magnitude events since 1950 are higher than over the period from 1850 and possibly as far back as 1400”.
Estimates using paleoclimate proxy data – which can be found in coral fossils and tree rings, for example – suggest that ENSO variability intensified by around 25% during the latter part of the 20th century compared to pre-industrial times.7Paleo-reconstructions typically have large uncertainty. A study published earlier this year estimates that human-caused warming has led to approximately one additional CP El Niño event and two additional extreme El Niño events since 1980. Despite the uncertainties, there is a growing consensus that human-caused warming is at least partly responsible for the changes in ENSO variability since the 1960s.
Higher temperatures during El Niño events are occurring against a backdrop of a warming Earth – thelast 11 years were the world’s hottest on record. This includes 2016, one of the strongest El Niño events on record, which saw unparalleled coral heat stress in the world’s oceans, resulting in extensive coral bleaching and die-off. ‘Pulse heat stress’ events, such as El Niño, may compound climate change-related stresses on humans and other organisms, with potentially irreversible consequences.8For instance, the 1982/1983 El Niño event led to the possible extinction of a coral species in Panama.
The years 2023-2025 are the hottest on record, with 2024 breaching the Paris-agreed average temperature target of 1.5°C. While a transgression of the Paris Agreement target would require at least 10 consecutive years above the threshold, it is a reminder that the world is rapidly approaching this limit and that temporary exceedances are already occurring. During an extreme El Niño event, an extra 0.2°C could be added to the average temperature of the Earth on top of elevated temperatures due to global warming. This means we could potentially see global average temperatures exceed 1.7°C this year.
Countries and ecosystems are already experiencing climate change-induced impacts, such as heatwaves, droughts and floods, and El Niño is likely to make these impacts worse.
Climate change makes it challenging to detect El Niño events
Continued global warming is making it increasingly difficult to predict El Niño events. Warmer seas and rising greenhouse gases from climate change complicate ENSO forecasts in several ways. Sea surface temperature (SST) anomalies in the region of the Central Pacific most usually measured to track changes (known as Niño 3.4) are traditionally measured relative to an average over a past reference period. As global temperatures rise, these values are increasingly likely to exceed these historical baselines, making it easier to register larger anomalies. This means the apparent strength of an event can depend on how recent the reference period is.
At the same time, variability in warming trends – with some regions warming faster than others – means that warming in Niño 3.4 does not necessarily reflect the same physical conditions as it did historically. Even if Niño 3.4 is warmer than average, warming across the rest of the tropics means it may not be especially warm relative to its surroundings, weakening or altering the atmospheric response that drives El Niño impacts.
To address this, the NOAA’s Climate Prediction Center increasingly uses relative SST anomalies, comparing Niño 3.4 temperatures to the tropical mean rather than a fixed historical baseline. This better captures whether the region is truly anomalous relative to its surroundings, and can significantly change how El Niño events are identified and interpreted in a warming climate.
Impacts of El Niño across the world
Predicting whether an El Niño event will occur, or how intense it will be, is challenging, mainly because predictions need to consider changes in both the Pacific Ocean and the atmosphere. While the characteristics of every El Niño event are different, our understanding of ‘teleconnections’ – whereby a climatic pattern, such as El Niño, is correlated with weather patterns elsewhere in the world – can be used to make predictions about the possible impacts. The figure below shows the typical weather impacts of El Niño across the world.
Figure 1. Global impacts of El Niño
El Niño does not have a uniform global effect (Figure 1). Hotter and drier conditions tend to occur in southern Africa, Australia, Indonesia and parts of South Asia, while wetter conditions are more likely in parts of the Americas (e.g. southern US, west coast of South America). Temperature changes also vary regionally, with some areas becoming warmer (e.g. northern US, Canada) and others becoming cooler (e.g., parts of the southern US).
As agriculture is highly sensitive to temperature and rainfall, these climate shifts translate into significant and uneven impacts on global crop production. El Niño causes significant grain yield reductions across around 22–24% of global harvested areas, particularly in regions that become hotter and drier (e.g., parts of Africa, Australia and South/Southeast Asia) (Figure 2). By contrast, positive yield impacts occur in around 30–36% of areas, often where conditions become wetter or more favourable (e.g., parts of the Americas). These effects vary by crop: globally, El Niño tends to reduce yields of maize, rice and wheat, while soybean yields often increase, driven by gains in major producing regions such as the US and Brazil.
Regionally, El Niño tends to negatively impact maize yields in parts of eastern and western Africa, Mexico, eastern and central US, Spain and parts of southern Europe, Mainland Southeast Asia, northern India, Indonesia, the Philippines, and parts of northern and eastern China, whereas positive effects could be observed in South America, eastern Australia and parts of southern Africa. Soybean yields are typically reduced in India but increased in South America. Rice shows gains in parts of Southeast Asia, eastern China, and southern South America, but losses in India, West Africa and some Southeast Asian regions. Wheat yields may be negatively impacted in Australia, the US, southern Europe, and parts of India and China, but positive gains in southern Africa and parts of South America (Figure 2).
Figure 2. Global impacts of El Niño on grain production
El Niño events also impact the likelihood of tropical cyclone activity in different regions. In the Atlantic, El Niño tends to increase the variability in the speed or direction of wind, which can suppress cyclone formation. In the Pacific, El Niño can cause stronger tropical storms due to the warmer water in the ocean. This means there could be slightly lower hurricane forecasts for the upcoming season across the Atlantic and more storm activity across the Pacific.
Regional Impacts
Africa
In East Africa, El Niño conditions tend to result in wetter ‘short rains’ (the second rainy season in November and December), which can cause flooding. There is also a strong link between the Indian Ocean Dipole (IOD) – the Indian Ocean counterpart of El Niño and La Niña, in which there is a difference in sea surface temperatures between the western and eastern Indian Ocean – and El Niño. When there is a positive IOD and EP El Niño, wetter short rains are amplified.
In southern Africa, drier than average conditions are expected under El Niño, resulting in decreased maize yields, while the opposite is anticipated in East Africa. In Kenya, the higher rainfall associated with the 2015-2017 El Niño cycle increased maize production by 17%, while drought conditions in southern Africa during the same period during the same period led to maize yield losses of up to 50% compared to the five-year average and affected over 40 million people, of whom 23 million required emergency aid. In some parts of drought-prone eastern Ethiopia, drought following El Nino has been linked to crop failures of 50-90%.
Drought caused by El Niño has also progressively depleted water resources in parts of southern Africa, with the 2024 El Niño reducing hydropower generation at Kariba Dam, which powers most of Zambia and Zimbabwe. Low water levels also exacerbate human-wildlife conflict and poaching, disrupt tourism activities, and cause women and children to walk further to collect water
During and after El Niño events, cholera incidence has been found to increase threefold in El Niño-sensitive areas in East Africa due to higher rainfall.
India
ForIndia, El Niño tends to weaken the monsoon rains and produce drier conditions, and experts warn that when an El Niño event follows from a La Niña year – as is the case presently – the monsoon rains may be particularly low.9This is dependent on various factors, such as lower Eurasian snow cover, which creates warmer conditions on the subcontinent, thereby bringing more rain to India. An assessment of rainfall trends over 132 years in India shows that severe droughts in the region have always been during CP El Niño years. However, if an EP event occurs, there is also a higher possibility of a positive IOD occurring, which brings drier conditions to the eastern Indian Ocean (in the region of India) and wetter conditions to the western Indian Ocean (in the region of eastern Africa).
Southeast Asia
In Java, Indonesia, El Niño tends to decrease rainfall. Decreased rainfall during El Niño periods has been linked to increased forest fires in Indonesia and reduced rice yields on Java where more than 50% of the country’s rice is grown. Fires in Indonesia are more intense and prolonged under an EP El Niño. However, fires are shorter and less intense during El Niño phases when the IOD is negative or weakly positive.
In the Philippines, El Niño is associated with reduced average rainfall and elevated drought conditions, particularly during December to May. The associated water shortages may negatively impact agricultural production in the region – the 2015/2016 El Niño event cost USD 327 million in agricultural production losses. In China, El Niño is linked to higher wintertime air pollution due to southerly winds that encourage the accumulation of particulates.
Europe
El Niño winters are associated with wetter conditions in southern Europe and colder, drier conditions in northern Europe. Latest outputs from weather prediction models suggest this summer will be warmer than average in Europe, with conditions average to wetter in the South and drier in the North.
Australia
In Australia, El Niño is expected to bring higher temperatures and fire risk, and lower rainfall. Previous events have caused drier than average winter-spring, but the exact extent of the impact is hard to predict.
North America
In the Northern US and Canada, El Niño is associated with warmer conditions, whereas in the southern US and northern Mexico, wetter, cooler conditions with increased flooding risk are expected. El Niño weakens Atlantic hurricane activity but increases Pacific hurricane activity.
Although uncertainty remains high regarding specific outcomes, it is possible that Atlantic Canada will see a cooler start to the summer season, while Western Canada will see more rapid warming, resulting in higher drought and fire risk.
El Niño may reduce wheat yields in the US as well as maize yields in the southeastern US, while soybean yields may increase.
South America
El Niño typically brings heavier rains and flooding risk to Ecuador, Peru, Uruguay, Paraguay, Argentina and Brazil, but below-normal rainfall to Colombia, Venezuela, Guyana, Suriname, Bolivia, eastern Peru, El Salvador, Guatemala, Honduras and Nicaragua. A CP El Niño brings drier conditions to the tropical Andes and northern South America, but wetter conditions to southeastern South America and the northwestern Peruvian Amazon. An EP El Niño is associated with increased rainfall along the coasts of Ecuador and northern Peru, and drier conditions in northeastern Brazil, the Amazon Basin, and the Andean Plateau, with some evidence of wetter conditions in southeastern South America.
Specifically, an EP El Niño is associated with reduced rainfall in northern, eastern and western Amazonia, with significant impacts on water and carbon cycling – whereby carbon is cycled between the atmosphere, organisms and minerals on earth. During EP El Niño events, lower rainfall occurs across all seasons in the Amazon, turning the Amazon into a net carbon source as trees dry out and slow their growth. During CP El Niño events, reduced rainfall is only observed during the summer wet season. Warmer, drier conditions in Colombia during El Niño have been linked to outbreaks of dengue fever and malaria.
This briefing was originally published in May 2023 and updated in April 2026.
