The El Niño climate pattern that is strengthening in the Pacific Ocean is on track to be the largest one in at least 150 years, researchers said today during a press briefing. If the monster forecasts they presented pan out, the surge of heat that the El Niño will unleash from the ocean, combined with warming from human-caused climate change, will probably make next year the hottest on record — and cue up extreme weather in many parts of the world.
Oceans in Asia smash heat records — what it means for extreme weather
According to the projections from a suite of climate models, the peak of this El Niño is set to surpass the previous record-holder by “truly, a mind-blowing margin”, says Zeke Hausfather, a climate scientist at Berkeley Earth, a non-profit research organization in California that hosted the briefing.
It’s “not outside the realm of possibility” that the event could combine with climate change to raise global average temperatures in 2027 as high as 1.7°C above the pre-industrial average, he said at the briefing. This would bring the planet right to the edge of breaching the 1.5°C threshold that governments pledged to avoid under the Paris Agreement.
The fact that an El Niño is occurring now isn’t surprising. The El Niño–Southern Oscillation (ENSO) is a natural fluctuation in sea surface temperature and winds in the tropical Pacific Ocean. Historically, it has swung between hot El Niños and cool La Niñas every two to seven years. The last El Niño took place in 2023–24 and, after forecasters had warned of a big event looming, this year’s emerged in June.
But the latest predictions suggest that this El Niño could become even bigger than anticipated. According to Justin Mankin, a climate researcher at Dartmouth College in Hanover, New Hampshire, it looks a lot like the ones that scientists had projected being amplified by human-caused climate change later this century.
Extreme forecasts
The elevated Pacific sea surface temperatures and wind patterns that are the hallmark of an El Niño have rapidly strengthened since June. In its latest advisory, the US National Oceanic and Atmospheric Administration (NOAA) gave a four in five chance of a “very strong” event developing by the end of the year, with near certainty that El Niño conditions will persist until at least April 2027.
“Right now, we’re seeing all the markers of very vigorous atmosphere–ocean coupling across the equatorial Pacific Ocean, which is giving us more confidence we will ultimately see a ‘very strong’ El Niño that would rank among the strongest El Niños in our historical record,” says Michelle L’Heureux, a meteorologist at NOAA who leads the agency’s ENSO prediction team in College Park, Maryland.
The NOAA forecast could be conservative, however. In a blog post last week and during the briefing today, Hausfather compared the projections from 14 climate models for this El Niño, and showed that the median estimate for peak sea surface temperature in the Pacific is about 0.8°C higher than the previous record set in 2015–16 (see ‘Record breaker’). “It’s by no means a foregone conclusion, but the likelihood has risen month over month,” he said.
Source: Zeke Hausfather/Berkeley Earth
In addition to the El Niño event raising global average temperatures to record highs in 2027, Hausfather says that there’s a fair chance that it will boost temperatures enough in the next few months to make 2026 a record hot year, too. The pattern of heatwaves, droughts, flooding and wildfires associated with El Niño will also have consequences for economies. Mankin and his colleagues have estimated1 that changes in weather attributed to a strong El Niño in 1997–98 shrank global economic growth by US$5.7 trillion in the years that followed.
If the forecasts are anything near correct, the current El Niño could cause “$10 trillion in economic losses by 2032”, Mankin says. Beyond impacts on human society, this El Niño is likely to stress ecosystems and oceans, driving declines in the net amount of carbon they take up from the atmosphere. Elevated ocean temperatures are also bad news for coral reefs bleached by the heat.
