The US National Oceanic and Atmospheric Administration (NOAA) says there is a greater than 90% chance that the current El Nino will become a very strong event during the Northern Hemisphere fall and winter.
NOAA also estimates a 69% chance that the event will surpass the strength of every El Nino recorded since 1950 during the October-December period.
Anadolu has compiled answers to 10 key questions about El Nino, its expected development and its possible effects around the world.
El Nino, which means “Little Boy” in Spanish, is the warm phase of the El Nino-Southern Oscillation, or ENSO, a recurring climate pattern involving changes in ocean temperatures, winds and atmospheric pressure across the equatorial Pacific.
It develops when sea surface temperatures in the central and eastern equatorial Pacific rise above their normal levels and the atmosphere responds to that warming.
NOAA monitors temperatures in an area known as the Nino-3.4 region. El Nino conditions are identified when relative monthly temperature departures reach at least 0.5C and are accompanied by consistent changes in atmospheric circulation.
For an event to be classified historically as a fully developed El Nino episode, the threshold must remain in place for at least five consecutive overlapping three-month periods.
El Nino events occur every two to seven years on average and generally last between nine and 12 months, although some continue for longer.
NOAA announced on June 11 that El Nino conditions had formed in the tropical Pacific.
The agency expects the event to continue strengthening through the end of 2026 and persist through the Northern Hemisphere spring of 2027.
Ocean temperatures are expected to peak around the October-December or November-January period before beginning to decline. El Nino conditions are forecast to weaken gradually during spring 2027.
Events in which the relevant three-month temperature index reaches around 2C above normal are commonly classified as very strong El Nino events. The 1982-83, 1997-98 and 2015-16 episodes were among the strongest in modern records.
According to NOAA’s Aug. 13 forecast, the current event has a greater than 90% chance of becoming very strong during fall and winter.
Sea surface temperature anomalies exceeded 2C in parts of the eastern equatorial Pacific in July. However, the monthly Nino-3.4 value, which covers the main monitoring region, was 1.4C above normal.
NOAA forecasts a 69% chance that the three-month Relative Oceanic Nino Index will reach at least 2.5C during October-December, which would exceed all previous El Nino events in its record dating to 1950.
The agency has stressed that a stronger event increases the probability of typical El Nino effects but does not guarantee that every region will experience them.
A strong El Nino can raise the global average temperature by approximately 0.2C, although its effect occurs on top of the longer-term warming caused by greenhouse gas emissions.
The Pacific Ocean covers nearly one-third of the Earth’s surface and serves as a massive source of heat and moisture for the atmosphere.
As surface waters warm during El Nino, evaporation increases and additional heat and water vapor enter the atmosphere. This can raise temperatures in some regions while contributing to powerful rain and storm systems elsewhere.
The area of intense tropical rainfall that is normally concentrated over the western Pacific also shifts eastward. This changes atmospheric pressure, trade winds, jet streams and other large-scale circulation systems, influencing weather thousands of kilometers away.
El Nino’s clearest and most predictable effects are generally seen in tropical regions, although no two events produce exactly the same outcomes.
Typical effects include heavier rainfall, flooding, landslides and coastal inundation in Peru and Ecuador, as well as an increased risk of drought in southern Africa, Colombia, Indonesia and Australia.
El Nino can weaken monsoon rainfall in India and contribute to warmer, drier conditions across parts of Southeast Asia.
In the US, it is generally associated with wetter conditions across southern states and warmer, drier winters in northern areas and Canada.
Southern Brazil can experience increased rainfall and flooding, while northern parts of the country face a greater risk of drought.
El Nino also tends to suppress Atlantic hurricane activity by increasing upper-level winds that can disrupt the development of tropical storms.
These patterns are tendencies rather than guarantees, as local conditions and other climate systems can strengthen, weaken, or reverse El Nino’s influence.
El Nino can increase wildfire risk in areas where it brings hotter and drier conditions, particularly in Australia, Indonesia, parts of South America and southern Africa.
Agriculture is among the sectors most exposed. Drought can reduce crop yields and damage pastureland, while excessive rain and flooding can destroy crops, disrupt planting and contaminate water supplies.
El Nino also affects marine ecosystems. Warmer waters can weaken the upwelling of cold, nutrient-rich water off South America, reducing plankton and affecting fish populations and the communities that depend on them.
Its wider consequences can include water shortages, higher food prices, disease outbreaks, displacement and increased humanitarian needs.
Previous El Nino events have caused economic disruption lasting years beyond the immediate period of droughts and floods.
A 2023 Dartmouth College study estimated that the 1997-98 El Nino was associated with about $5.7 trillion in cumulative global income losses during the following five years.
The UN Food and Agriculture Organization has warned that parts of southern and Southeast Asia, Central America, the Caribbean, the Sahel and southern Africa face a greater than 50% probability of agricultural drought during important growing periods.
The World Food Program estimates that the 2026-27 El Nino could push at least 49 million additional people into acute food insecurity by the end of 2027.
Reduced harvests can increase the prices of internationally traded products such as rice, maize, coffee, cocoa, sugar and palm oil. Floods and storms can also disrupt transport, energy infrastructure and supply chains.
Türkiye is not among the regions where El Nino has its strongest or most consistent effects.
Any influence is generally indirect, operating through changes in large-scale atmospheric circulation and interactions with other systems, including the North Atlantic Oscillation and regional Mediterranean weather patterns.
Some studies have identified a tendency toward drier Mediterranean winters during certain types of El Nino events. However, the relationship is not consistent enough for El Nino alone to determine whether Türkiye will experience a warm, dry or wet season.
Persistently high temperatures and low rainfall could increase drought and wildfire risks, but more detailed seasonal forecasts are needed to assess conditions in Türkiye.
La Nina, meaning “Little Girl” in Spanish, is the cooler phase of ENSO.
It develops when sea surface temperatures in the central and eastern equatorial Pacific fall below normal and are accompanied by corresponding changes in atmospheric circulation.
While El Nino tends to temporarily raise global temperatures, La Nina generally has a temporary cooling influence.
Their regional effects are often opposite. For example, La Nina can bring wetter conditions to Australia and Indonesia, while increasing drought risks across parts of the southern US.
However, La Nina does not always immediately follow El Nino. The Pacific can instead return to neutral conditions, when neither warm nor cold ENSO conditions are dominant.
There is no complete scientific consensus on precisely how climate change will affect the strength, frequency and geographical pattern of future El Nino events.
El Nino is a naturally occurring climate phenomenon and existed long before human-caused global warming. However, it now occurs in an atmosphere and ocean system that is considerably warmer.
A 2023 study published in Nature Reviews Earth and Environment found that more than three-quarters of the climate models examined produced an increase in ENSO variability after 1960.
The modeling indicated an increase of approximately 10% in the strength of temperature variations compared with the 1901-1960 period, suggesting a possible greenhouse-warming influence.
Scientists say more research is needed to determine how much of the observed change is caused by greenhouse gases and how much results from natural variability.
Even if El Nino itself does not become stronger, its effects can become more damaging because it is occurring against a backdrop of higher temperatures, rising sea levels and more intense climate extremes.
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