Scientists in the US have announced that El Niño, a natural climate phenomenon in the Pacific Ocean that is usually associated with rising global temperatures, has officially begun.
The US National Oceanic and Atmospheric Administration (NOAA) confirmed that El Niño conditions are already present in the tropical Pacific, where sea surface temperatures have increased significantly in recent months.
The development was not unexpected. Meteorologists had predicted this warming phase after the end earlier in the year of La Niña, El Niño's colder "sister" phenomenon.
Many forecasts suggest that this could be a so-called "super" El Niño, even one of the strongest ever recorded.
Combined with decades of human-induced global warming, this phenomenon could lead to another record year for temperatures – likely in 2027 – as well as major disruptions to weather patterns, food supplies and global economies. Its consequences are expected to be felt widely and deeply during that year.
Confirmation of scientists
Sea surface temperatures in the central and tropical Pacific have already exceeded the threshold of 0.5°C above average, the level that US scientists use as an indicator for declaring El Niño.
In a statement, NOAA said that "conditions for El Niño have developed over the past month, as indicated by above-average sea surface temperatures in the central and eastern equatorial Pacific."
The US agency also notes that winds over the equatorial Pacific are starting to change direction and intensity, which is seen as an important signal that the atmosphere is responding to ocean warming – and not simply that the ocean is warming in isolation.
Models predict record power
What has surprised researchers is the high level of confidence that computer models now show about the strength of this phenomenon. The intensity of El Niño is measured by the increase in sea surface temperatures above average in a key area of the Pacific.
An event is considered strong when the temperature rises above 1.5°C above average, while a very strong event when it exceeds 2°C.
According to NOAA's June forecast, there is a 63% chance of a very strong El Niño occurring between November and January. Such a development would rank it among the most extreme events recorded since 1950, when modern climate records began.
Since then, three of the strongest El Niños have occurred in 1982/83, 1997/98 and 2015/16.
Meanwhile, some of the latest American and European models go even further, suggesting that by the end of the year temperatures in the tropical Pacific could rise by more than 3°C above average.
However, the US agency has urged caution in interpreting the forecasts. “Even very strong El Niño events do not necessarily have the same consequences in every region, but more intense events can significantly increase the likelihood of typical El Niño developments and impacts,” the statement said.
Global warming is amplifying the consequences
The biggest concern, according to experts, is that this entire phenomenon is happening on a planet that is already significantly warmer.
"We need to worry about the consequences," said Professor Adam Scaife, head of forecasting at Britain's Met Office.
He added that "the current El Niño is superimposed on significant global warming. This means that temperatures in affected regions could be unprecedented, as the warming caused by El Niño adds to existing climate change."
According to him, a strong El Niño typically increases global air temperatures by about 0.2°C, releasing heat accumulated in the oceans into the atmosphere.
This additional impact is hitting a world that is already setting consecutive temperature records.
2024 was the hottest year on record, driven by an El Niño that was not considered particularly strong. Meanwhile, despite the cooling effect of the La Niña phenomenon, 2025 was still the third hottest year on record – even hotter than 2016, which saw one of the strongest El Niños on record.
"By the end of this year and into 2027 we are likely to see very high global temperatures," said Professor Adam Scaife.
He added that "in 2027 we could face a new extreme heat wave, on top of existing global warming, which could easily lead to another year where the average global temperature exceeds 1.5°C compared to late 19th century levels."
Droughts, floods and fires around the world
No two El Niño are the same, but its effects are usually felt most strongly in tropical areas.
Flooding is common in northern Peru and southern Ecuador, while other impacts could extend to parts of eastern Africa, central Asia and the southern United States.
At the same time, the risk of droughts and forest fires is increasing in large areas of Australia, Indonesia and northern South America. These changes could have direct consequences for agriculture and global food security.
El Niño also usually brings a decrease in hurricane activity in the Atlantic, and forecasters are already expecting a quieter-than-average season.
"While this may sound like good news, for Central America it means less rainfall and increased risk of drought," said Liz Stephens, professor of climate risk at the University of Reading.
For many, this prediction is not just an abstract matter. “The declaration of El Niño is not just another weather forecast – for millions of people it is a serious alarm that must be taken very seriously,” said Mohamed Adow, director of the organization Power Shift Africa .
He added that this situation means a lack of rainfall, crop failures, rising food prices and pushing families to the brink of survival. According to him, in East Africa in particular, the impacts will be felt, hitting communities that have already faced droughts and floods in recent years.
Not all agencies are of the same opinion.
The Japan Meteorological Agency (JMA) shares the same assessment as NOAA, considering that conditions for El Niño are already present and adding that they will almost certainly continue until the fall. However, not all agencies are ready to officially declare the phenomenon yet.
Unlike the JMA and NOAA, the Australian Bureau of Meteorology (BoM) uses a stricter criterion for declaring El Niño, requiring sea surface temperatures to be at least 0.8°C above average.
This week, meteorological authorities announced that the tropical Pacific is “approaching El Niño conditions,” as temperatures in the central Pacific have already crossed the relevant thresholds. However, they have refrained from officially declaring the phenomenon’s onset, stressing that it is expected to develop later this year and could be strong.
El Niño typically occurs every two to seven years and lasts about a year. Currently, there is no conclusive evidence that climate change is making this phenomenon more frequent or more intense, but a warming planet could significantly amplify its effects. /Telegraph/