Weather Experts Update El Niño Tracking Due to Rising Global Temperatures

Climate researchers have revised how they identify El Niño and La Niña weather patterns because global warming has made traditional measurement methods outdated. A new study suggests an unusual three-year La Niña cycle helped explain the dramatic temperature spike Earth experienced from 2023 to 2025.

WASHINGTON — Weather experts are revising how they track El Niño patterns as global warming continues to alter traditional climate measurements, according to new research from meteorologists.

Fresh analysis published this month reveals that an uncommon extended cooling period helped scientists understand why Earth’s temperatures jumped dramatically over the last three years, beyond the steady warming trend linked to human activities.

The U.S. National Oceanic and Atmospheric Administration has modified its method for determining when these influential weather cycles begin and end. Rising ocean temperatures worldwide forced NOAA to update their calculations, which will likely result in more La Niña events being identified and fewer El Niño periods being declared.

Global monthly temperatures made a significant leap above the long-term warming pattern in early 2023, continuing through 2025. Researchers have proposed various explanations for this jump, including accelerated greenhouse gas effects, reduced ship pollution particles, underwater volcanic activity, and increased solar energy.

New research published in Nature Geoscience by Japanese scientists examined how Earth’s energy balance — the difference between incoming and outgoing energy — shifted in 2022. When this balance tips toward more trapped heat, temperatures rise accordingly. The study found that roughly three-quarters of this energy change resulted from both long-term human-caused warming and the transition from an extended La Niña cooling phase to a warming El Niño period.

El Niño represents a natural cyclical warming of specific equatorial Pacific Ocean areas that disrupts global weather patterns, while La Niña involves cooler-than-normal waters in the same regions.

These phenomena affect rainfall and temperature patterns differently across the globe. El Niño events typically boost worldwide temperatures, while La Niña periods suppress the overall warming trend.

Research indicates La Niña conditions generally create more destructive impacts for the United States through enhanced hurricane seasons and drought conditions.

Between 2020 and 2023, Earth experienced an uncommon “triple dip” La Niña period without any intervening El Niño phase. During La Niña conditions, warmer water remains at deeper levels, creating cooler surface temperatures. This reduces the amount of energy released into space, explained study co-author Yu Kosaka from the University of Tokyo.

Kosaka drew a comparison to human fever responses.

“If our body’s temperature is high then it tends to emit its energy out, and the Earth has the same situation happening. And as the temperatures increase, it acts to emit more energy outward. And for three-year La Nina, it’s opposite,” Kosaka said.

This traps more energy — which converts to heat — on Earth, she explained. While La Niña periods typically create one or two years of extra energy buildup, this extended cycle lasted longer, making the effects more pronounced and producing higher temperatures.

“When there is a transition from La Nina to El Nino, it’s like the lid is popped off,” releasing the accumulated heat, explained former NOAA meteorologist Tom Di Liberto, now with Climate Central.

The study authors determined that approximately 23% of the energy imbalance driving recent temperature increases stems from this unusually prolonged La Niña pattern, while slightly more than half comes from fossil fuel emissions. Other factors account for the remainder.

Jennifer Francis from the Woodwell Climate Research Center, who wasn’t part of the study team, said the findings make logical sense and explain an energy imbalance increase that some researchers had attributed to accelerated warming.

For seven and a half decades, meteorologists have identified El Niño and La Niña events by comparing temperatures in three tropical Pacific areas to normal conditions. El Niño was defined as 0.5 degrees Celsius (0.9 degrees Fahrenheit) above normal, while La Niña was the same amount below normal.

The challenge in our warming world is that “normal” temperatures keep changing.

Previously, NOAA used 30-year temperature averages as their baseline, updating these averages every decade along with other climate measurements. As waters warmed significantly, NOAA switched to updating the baseline every five years, but this still proved insufficient, according to Nat Johnson, a meteorologist at NOAA’s Geophysical Fluid Dynamics Lab.

NOAA introduced a relative El Niño index this month that compares temperatures to other tropical regions worldwide. The difference between old and new methods has recently reached half a degree Celsius (0.9 degrees Fahrenheit), “and that’s enough to have an impact,” Johnson said.

The key factor with these weather patterns is how ocean waters interact with the atmosphere. Recent interactions didn’t align with the previous labeling system but do correspond with the updated method, Johnson noted.

This change will probably result in slightly more La Niña identifications and fewer El Niño declarations compared to the former system, Johnson said.

NOAA’s current forecast predicts an El Niño development later this year during late summer or fall. If it arrives early enough, it could reduce Atlantic hurricane activity. However, it would also mean higher global temperatures in 2027.

“When El Nino develops, we’re likely to set a new global temperature record,” Woodwell’s Francis said in an email. “‘Normal’ was left in the dust decades ago. And with this much heat in the system, everyone should buckle up for the extreme weather it will fuel.”