Superstrong El Niño

ClimateBrink: “The Strongest El Niño Ever.”

This is from a substack post by Zeke Hausfather, who gets points just for his name. “With the July runs now in from 667 ensemble members across 14 different seasonal forecast models, it looks like 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.”

The multi-model median for the event’s peak (measured as ‘detrended’ sea surface temperature anomalies in the Niño 3.4 region of the tropical Pacific) currently stands at 3.6ºC, roughly 0.8ºC hotter than the prior record of 2.75ºC set in 2015–16. “No event in a century and a half of observations has ever pushed meaningfully past 2.75ºC.” The legendary 1877–78 event comes closest, in a statistical dead heat with 2015–16 (2.73ºC vs 2.75ºC, well within the uncertainty of 19th-century ship data).”

“The 2026 event is developing faster than 1997–98, the previous gold standard for explosive El Niño onsets.” And unlike 2015 which started its year already warm from a precursor event, this one launched from genuinely La Niña-ish conditions in January.

“In a warming world, the raw Niño 3.4 anomaly risks conflating El Niño with the broader ocean warming trend.” NOAA’s answer is the “Relative Oceanic Niño Index (RONI),” which subtracts the tropical-mean SST anomaly to isolate the ENSO signal.

Aggregating all the models together, Hausfather projects a ~91% chance of a record peak in Niño 3.4 terms and ~77% in RONI terms this year. Whichever way you slice the index, the forecast says the same thing: this is more likely than not to be the strongest El Niño ever observed.

Clearly, time to batten down the hatches. Just as clearly, time to aggressively address the weirding climate.