El Niño warming Pacific at record pace, scientists warn of uncharted territory

El Niño is already here and warming the Pacific Ocean at the fastest pace on record, with scientists warning of impacts that could be "mind-blowing."

As of July, ocean temperatures in the Niño 3.4 region—the zone used to define El Niño conditions—are close to 2°C above average. In order to be considered an El Niño, temperatures need to be 0.5°C above average. Zeke Hausfather, a climate scientist with Berkeley Earth, a non-profit climate analysis organization, said the region is "already touching a very strong El Niño conditions, and it's early July still."

Forecasts suggest the peak will occur sometime between October and December, with models predicting ocean temperature anomalies around 3.6°C. That would exceed the strongest El Niño in recent years—the 2015-2016 event, where the anomaly was roughly 2.75°C, and what is believed to have been a comparable event in 1877-1878. "We might end up breaking the previous El Niño record by a truly mind-blowing margin," Hausfather said.

The transition from La Niña (cooler conditions) last winter to a potentially super El Niño this year happened very quickly—a shift that researchers are still studying. Climate change's role in the rapid transition remains an open question, though researchers note there have been fewer neutral years in the Niño 3.4 region and bigger swings between El Niño and La Niña events in recent decades.