A rapidly developing El Niño event has already reached record-setting levels for this time of year and is projected to intensify further in the coming months, according to climate scientists cited by New Scientist and other outlets tracking the phenomenon.
Climate scientist James Hansen of Columbia University wrote in a newsletter that the El Niño has “blossomed” and is “off the charts,” with commonly used measures already surpassing prior record levels for this point in the cycle, even though the event’s peak effects are still months away.
Separately, climate scientist Zeke Hausfather of Berkeley Earth analyzed July forecast runs from 667 ensemble members across 14 seasonal forecast models and concluded the event is very likely to be the strongest since reliable records began, potentially by a wide margin. Hausfather, who has described himself as generally measured in his interpretation of climate data, compared his reaction to the July data to his response to global temperature records set in September 2023.
A separate analysis by climate site Carbon Brief, using the same 14 modelling groups, found that 96% of forecast runs predict the event will be the strongest in the modern observational record. The U.S. National Oceanic and Atmospheric Administration (NOAA) said in a forecast released in mid-August that there is a nearly 70% chance the event will set a new record.
Scientists have also pointed to the unusual speed at which the event developed. The tropical Pacific was still in La Niña conditions, marked by cooler than average temperatures, as recently as winter 2025. Meteorologist Michelle L’Heureux of NOAA’s Climate Prediction Center, cited by the journal Science, said a swing this rapid from La Niña to a very strong El Niño has not been observed since data collection began in the 1950s.
NOAA has projected that tropical Pacific waters could warm by up to 2.4 degrees Celsius above average by November if current forecasts hold.
El Niño occurs when warm surface waters spread eastward across the tropical Pacific Ocean, transferring large amounts of heat into the atmosphere. Scientists cited by CNN said the effects of a stronger El Niño are not necessarily more severe in every location, but that a stronger signal makes the typical regional effects, referred to as teleconnections, more likely and more predictable to occur.
Climate scientist Daniel Swain of the University of California said the event was already at record-tying territory and was expected to intensify further. Researchers have said the event is developing against the backdrop of a global climate that is already warmer than during any previous strong El Niño, including the events of 1982-83, 1997-98, and 2015-16, which could influence its effects on heat waves, drought, and flooding.
Scientific Debate
Not all climate scientists agree the event has already surpassed previous “super El Niño” years on every metric. Different institutions use different methods to measure El Niño strength, including sea surface temperature anomalies and subsurface ocean heat content. Hansen said his preferred metric is the heat anomaly in the upper 300 meters of the eastern tropical Pacific.
Scientists noted that El Niño and La Niña events typically last 9 to 12 months, and this event, which began in June, is expected to continue into 2027.
