El Niño is a naturally occurring climate phenomenon that can cause drenching rains in one part of the world and drought in another. Scientists identify it by looking at deviations in temperature levels in the Pacific Ocean, most commonly in a region known as Niño 3.4.
Exceptionally warm sea surface temperatures in the Pacific Ocean are setting the stage for a potential “super” El Niño of record-breaking intensity.
Temperatures in a part of the equatorial Pacific that’s closely monitored to define El Niño and La Niña events are currently at 29.4C (84.9F), or 1.7C above the 30-year average, according to the latest data from US National Oceanic and Atmospheric Administration. That’s on track to be the largest warm deviation from the historical average for June since 1981, the data show.
El Niño is a naturally occurring climate phenomenon that can cause drenching rains in one part of the world and drought in another. Scientists identify it by looking at deviations in temperature levels in the Pacific Ocean, most commonly in a region known as Niño 3.4.
NOAA defines a strong El Niño as one in which the temperature is at least 1.5C above the long-term average, and a very strong or “super” El Niño as one in which the temperature difference is at least 2C. While 2C may not seem like a lot, a huge amount of energy is needed to heat up such a large volume of open water.
“The data show these incredibly warm temperatures,” said Benjamin Horton, chair professor of earth science at the City University of Hong Kong, referring to the Niño 3.4 region.
Even more worrying, he said, is how quickly temperatures in the equatorial Pacific have risen to abnormally warm levels from below normal temperatures just earlier this year. Scientists “have seen water temperatures like this before, but they have never seen the intensification, the rate of change, as we moved out of La Niña” earlier this year, Horton said.
The US Climate Prediction Center, part of NOAA, currently predicts an 89% chance of El Niño reaching at least strong intensity by December, and a 62% that it will be very strong by that time.
While a strong El Niño makes severe weather impacts more likely, the correlation is not a certain one. Another consideration is how long the El Niño lasts, and current forecasts do not provide much guidance beyond early 2027.
A minor, short-lived El Niño will not break global temperature records, Horton said, while a minor and long-lived one will. “And if you have a major one that’s moderate to long-lived, we’ll smash them,” he said.
“Long El Niño can last up to 18 months,” Horton said. “But maybe we’ll stay in it for 24 months. You don’t know.”