The world could face the strongest El Niño since recordkeeping began, increasing the likelihood of extreme weather events and significant, long-term economic impacts globally.

A new analysis by Berkeley Earth climate scientist Zeke Hausfather paints a worrying picture of the climate phenomenon developing in the Pacific Ocean. Models have consistently forecast that this year’s El Niño—characterized by hotter than normal waters in the eastern tropical Pacific—could be among the strongest on records. Hausfather’s analysis using the El Niño forecast based on 14 climate models through July indicates that “this year’s El Niño is not only very likely to be the strongest event since reliable records began—it may end up the strongest by a truly mind-blowing margin.”

Climate researchers measure the strength of El Niño by looking at the temperatures in a region of the Pacific known as Niño 3.4, which covers the eastern and central part of the ocean basin. The new analysis relies on 667 simulations and compares them with historical records of the most intense El Niño events since 1877. It also disentangles El Niño’s intensity from the background warming driven by fossil fuels, making it easier to draw comparisons between super El Niños.

The model average shows that heat in the Niño 3.4 region could peak at 3.6 degrees Celsius (6.5 degrees Fahrenheit) above normal levels. This figure would exceed the previous record—set during the 2015-2016 El Niño episode—by approximately 0.8 degrees Celsius. It’s rare for records to fall by such a wide spread.

“For context, the gap between the strongest and the fifth strongest El Niño of the past 150 years is only about 0.5C. The models are forecasting something outside the envelope of anything we have ever observed,” Hausfather writes.

Of course, what happens in the tropical Pacific doesn’t stay in the tropical Pacific. El Niño rearranges the atmosphere, changing weather patterns around the world. The more intense the El Niño, the more intense the impacts (usually).

Record-breaking ocean heat in the Pacific combined with warming driven by carbon emissions could send the global temperature to new highs. But it takes a while for the extra heat released by El Niño to work its way through the vast climate system, meaning that next year is when we’ll see the full impact of this year’s Pacific heat wave on the global average temperature. According to his projections, global temperatures in 2027 could reach up to 1.7 degrees Celsius above the preindustrial average, well above the 1.5 degrees Celsius threshold that’s been dubbed a relatively safe level of global warming.

But the world won’t have to wait until 2027 to feel the heat of El Niño. A separate analysis by Carbon Brief shows that the odds are increasing for 2026 to set an annual heat record, with the likelihood up from 19 percent in April to 35 percent as of July. And the forecasters are expecting extreme weather associated with El Niño to impact various parts of the globe in the coming months. In fact, some impacts are already here: Fisheries in the eastern Pacific are seeing lower catches, with the Peruvian government setting up a ban for catching anchovies this spring.

Hausfather’s analysis also revealed that the phenomenon is developing faster than usual. According to the comparison, this year’s El Niño is intensifying more rapidly than the 1997-1998 event, another super El Niño. It also differs significantly from the 2015 event, which began when the ocean was already showing signs of prior warming—in other words, it had a running start. That’s particularly striking because this year began with La Niña, the cooler-than-normal cousin of El Niño, so it had a bit of work to do before it even got going.