US climate agency confirms El Niño begins as gloEl Niño — the natural climate pattern in the Pacific that typically drives up global temperatures — has officially begun, according to US scientists.
The US National Oceanic and Atmospheric Administration confirmed that El Niño conditions are now established across the tropical Pacific, following a rapid rise in sea surface temperatures in recent months.
Some forecasts even suggest this could develop into a “super” El Niño, potentially ranking among the strongest ever recorded.
Combined with long-term human-induced global warming, the event could contribute to another record-hot year, likely in 2027, with widespread impacts on weather systems, food production, and global economies expected to extend into that period.
NOAA’s announcement comes as little surprise, with forecasters already anticipating a transition from the cooler La Niña phase, which ended earlier this year.
Sea surface temperatures in the central and tropical Pacific have now crossed the 0.5°C-above-average threshold used by US scientists to classify an El Niño event.
“El Niño conditions developed over the past month, as shown by above-average sea surface temperatures across the central to eastern equatorial Pacific Ocean,” the agency said.
The agency also noted changes in atmospheric wind patterns over the equatorial Pacific, indicating that the atmosphere is beginning to respond to ocean warming, a key sign that the event is fully coupling between ocean and air systems.
What has particularly stood out to researchers is the growing confidence in model projections regarding its potential intensity.
El Niño strength is measured by how much sea surface temperatures rise above average in a key Pacific region. Events exceeding 1.5°C are considered strong, while those above 2°C are classified as very strong.
According to NOAA’s June outlook, “there is a 63% chance of a very strong El Niño during November-January, that would rank among the largest El Niño events in the historical record going back to 1950,” the agency said.
Historically, the most powerful El Niño events occurred in 1982/83, 1997/98, and 2015/16.
Some updated US and European climate models go even further, suggesting tropical Pacific temperatures could rise by more than 3°C above average toward the end of the year.
However, NOAA has urged caution in interpreting these projections strictly in terms of impacts.
“Even very strong El Niño events do not lead to the expected impact everywhere, but stronger events can more significantly tilt the odds in favour of expected outcomes.”
The concern is amplified by the fact that this El Niño is forming on top of an already significantly warmed planet.
“We do need to worry about the impacts,” said Prof Adam Scaife, head of monthly to decadal prediction at the UK Met Office.
“The current El Niño is… riding on top of a substantial amount of global warming.
“This means that the actual temperatures in affected regions could well be unprecedented, as the warming from El Niño is being topped up by climate change.”
Typically, a strong El Niño adds around 0.2°C to global average temperatures by releasing stored ocean heat into the atmosphere, an effect now superimposed on an already record-warm baseline.
The year 2024, already the hottest on record, was influenced by an El Niño that was not especially intense.
Even with a cooling La Niña phase afterward, 2025 still ranked as the third warmest year ever recorded, surpassing even the strong 2016 El Niño year.
“At the end of this year and into 2027, we’re likely to see very high temperatures globally,” Prof Scaife said.
“In 2027, we’re likely to see excess heat on top of the global warming we’ve already got, and that could easily lead to another year above 1.5 degrees [of warming above late-19th-Century levels].”
While El Niño patterns vary, their global effects are often severe, especially across tropical regions.
Heavy rainfall and flooding are common in northern Peru and southern Ecuador, and can also extend into East Africa, Central Asia, and parts of the southern United States.
At the same time, drought and wildfire risks increase across Australia, Indonesia, and northern South America, with serious consequences for agriculture and global food supply chains.
El Niño also tends to suppress Atlantic hurricane activity, and forecasters already anticipate a quieter-than-usual season.
“While that sounds like a good thing, for Central America that leads to a lot less rainfall and potentially drought conditions,” said Liz Stephens, professor of climate risk and resilience at the University of Reading.
Even in the UK, impacts can be felt indirectly, with El Niño sometimes linked to milder starts to winter followed by colder finishes, although these connections are relatively weak.
For vulnerable regions, the stakes are far higher.
“An El Niño declaration is not just another weather forecast – for millions of people it is a deadly siren to be feared,” said Mohamed Adow, director of campaign group Power Shift Africa.
“It means failed rains, dying crops, rising food prices, and families pushed to the edge yet again. In East Africa especially, this will land on communities already battered by droughts and floods in recent years.”
Japan’s Meteorological Agency has also confirmed that El Niño conditions are present, with expectations that the event will persist into the autumn.
However, not all agencies agree on timing. Australia’s Bureau of Meteorology (BoM) uses a stricter threshold, requiring sea surface temperatures to exceed 0.8°C above average before officially declaring El Niño.
It said this week that the Pacific is “approaching El Niño conditions,” with central ocean temperatures already meeting key criteria, but it has not yet formally declared the event.
Still, it expects El Niño to develop later in the year and potentially become strong.
El Niño typically occurs every two to seven years and lasts around 12 months.
While there is still no definitive proof that climate change is increasing the frequency or strength of these events, scientists agree that a warmer planet is intensifying their impacts.
