Scientists Warn El Niño Could Return in 2026, Putting 2027 Heat Records at Risk

El Niño odds rise as La Niña fades

The tropical Pacific Ocean is still in the grip of a fading La Niña, a pattern that tends to cool the planet slightly. But below the surface, a pool of warm water is spreading eastward—an early sign that the climate system could be gearing up for an El Niño later this year.

If that swing happens, several leading climate scientists say 2027 is poised to challenge, and possibly surpass, 2024 as the hottest year ever recorded.

A coin flip with high stakes

Computer models monitored by major forecast centers show roughly even odds that El Niño—the warm phase of the El Niño–Southern Oscillation (ENSO)—will develop in the second half of 2026.

“For June to August, the chances of El Niño versus neutral conditions are about 50-50, or like tossing a coin,” said Andrea Taschetto, an associate professor at the University of New South Wales who specializes in ENSO.

Those odds are far from a guarantee. But because global temperatures typically peak in the year after an El Niño crests, a 2026 event would put 2027 squarely in focus.

“If we do get another moderate to strong El Niño developing later this year, then 2027 will likely set a new global temperature record,” said Zeke Hausfather, a climate scientist at the nonprofit research group Berkeley Earth.

La Niña on the way out

For now, La Niña still has the upper hand.

On Jan. 8, the U.S. National Oceanic and Atmospheric Administration’s Climate Prediction Center kept a La Niña advisory in place, reporting that sea-surface temperatures in a key stretch of the central equatorial Pacific—the Niño-3.4 region—were about 0.5 degrees Celsius below average in December, near the threshold for a weak La Niña.

Australia’s Bureau of Meteorology, in a Feb. 3 update, also judged that La Niña conditions were present, with the Niño-3.4 index at minus 0.75 degrees. But both agencies highlighted signs of change. Trade winds and atmospheric pressure patterns that normally reinforce La Niña have begun to weaken, and warmer-than-average waters below the surface are expanding eastward beneath the Pacific.

That subsurface warmth is closely watched by forecasters because it often precedes a swing toward El Niño if the overlying trade winds relax.

“The precursors are there,” said Andrew Watkins, a climate scientist at Monash University in Melbourne and former head of long-range forecasting at the Bureau of Meteorology. “We’ve got a pool of warm water sitting in the western Pacific. If the trade winds weaken, that can slosh east and set up an El Niño. But at this stage, it’s still too early to be sure that will happen.”

NOAA estimates a 75% chance that La Niña will give way to neutral conditions between January and March, with neutral likely to persist through at least late spring in the Northern Hemisphere. The World Meteorological Organization has similarly said the odds of El Niño forming before April are “negligible.”

Models hint at El Niño later in 2026

Beyond spring, the picture grows fuzzier—and more interesting.

A multi-model ENSO outlook compiled in January by the International Research Institute for Climate and Society at Columbia University shows neutral conditions dominating through early northern spring. After that, the probability of El Niño rises steadily, becoming the single most likely category by midyear.

By June to August, the models cluster around approximate odds of 48% to 51% for El Niño, with neutral conditions still a strong contender at roughly 37% to 46%. The chance of La Niña returning drops into the single digits.

Meteorologists caution that these percentages are not precise forecasts. ENSO predictions that cross boreal spring run up against what is known as the “spring predictability barrier,” a period when the climate system is inherently harder for models to judge.

“Forecast skill is lower in this season, and model disagreements are larger,” the Bureau of Meteorology warned in its February statement, stressing that indications of El Niño developing from June should be treated with “very high uncertainty” at this stage.

Why 2027, not 2026, is the bigger concern

Even if an El Niño does form later this year, scientists say 2027 is the year most likely to feel the full impact.

Historically, the global thermometer tends to spike in the year after an El Niño peaks. The powerful 1997–98 event helped propel 1998 to the top of temperature records at the time. The strong 2015–16 El Niño preceded 2016 becoming the warmest year then observed. More recently, an El Niño that developed in mid-2023 and faded in early 2024 helped make 2024 the hottest year on record.

Analyses by NASA and NOAA attribute a boost of around 0.1 to 0.2 degrees Celsius to those strong El Niños, superimposed on a steadily rising baseline of human-caused warming. Hausfather estimates the 2023–24 El Niño added about 0.12 degrees to 2024’s global average temperature, a figure broadly in line with past events.

“If we repeat that dynamic—with an El Niño peaking over the 2026–27 northern winter—then the extra heating effect would likely be most pronounced in the 2027 annual average,” he said.

A record threat on a record-hot baseline

What worries many researchers is not only the potential arrival of El Niño, but the climate state into which it would emerge.

Global monitoring agencies agree that the last decade has been extraordinary. NASA ranks 2024 as the hottest year since modern records began in the late 19th century. It places 2025 among the three warmest years, with a global average temperature about 1.19 degrees Celsius above the 1951–1980 average.

The European Union’s Copernicus Climate Change Service has reported that the period from 2023 through 2025 marked the first time a three-year average temperature has exceeded 1.5 degrees above preindustrial levels—the threshold countries hoped to “pursue efforts” to limit long-term warming under the 2015 Paris Agreement. The past 11 years are the 11 warmest on record.

Earth’s oceans are absorbing much of that excess heat. A recent assessment found that in 2025 the upper oceans took up about 23 zettajoules of heat—the ninth consecutive year to set a new record for ocean heat content. One research group described that rate as roughly equivalent to the energy of 12 Hiroshima-size nuclear bombs being released into the oceans every second.

Sea-surface temperatures in 2025 were the third highest observed, averaging about 0.5 degrees above the 1981–2010 norm.

Against that backdrop, Watkins said it no longer takes a “super El Niño” to rewrite the temperature record books.

“Anthropogenic warming from greenhouse gases is now so strong that we can break records even in neutral years,” he said. “El Niño just loads the dice further toward very extreme outcomes.”

Asked how he would rate the chances that 2027 ends up as the warmest year on record if an El Niño develops, Watkins replied, “I’d be hesitant to bet against a hottest year on record in that scenario.”

What another hot El Niño year could bring

An El Niño in late 2026 and a record-hot 2027 would have wide-reaching consequences.

Historically, El Niño tilts rainfall and temperature patterns around the globe. Australia, Southeast Asia and parts of southern Africa often see drier-than-average conditions, heightening drought and bushfire risks. Some areas of the Americas, including parts of the west coasts of North and South America, can receive heavier rains and flooding.

In a hotter climate, those shifts can be more damaging. Warmer oceans allow storms to carry more moisture, raising the potential for intense downpours and landslides. On land, prolonged heat and dryness can prime forests and grasslands for explosive wildfires.

Heatwaves are a central concern. In recent years, large parts of Europe, North Africa, the Middle East, South Asia and the Americas have experienced prolonged spells of extreme heat, with nighttime temperatures staying high. Health studies link such events to rising hospital admissions and tens of thousands of excess deaths, especially among older people, outdoor workers and those without access to cooling.

Agriculture is also vulnerable. El Niño-related droughts in past decades have cut yields of key crops such as wheat, maize and rice in several regions, contributing to higher food prices and, in some cases, political unrest.

Energy systems and infrastructure could face simultaneous pressures: surging electricity demand for air conditioning, reduced river flows for hydropower, and heat stress on roads, rails and airports.

Economic losses from climate-related disasters are already large. One recent global analysis estimated weather and climate events caused about $224 billion in losses and more than 17,000 deaths in 2025 alone.

Planning under uncertainty

Despite the elevated risks, scientists stress that no one can say in February whether El Niño will actually arrive in late 2026, how strong it might be, or exactly how high global temperatures will climb in 2027.

Forecasts will be updated monthly by NOAA, the Bureau of Meteorology, the World Meteorological Organization and other centers as new data come in and the Pacific’s behavior becomes clearer, especially after the spring predictability barrier.

For governments and businesses, several experts say the prudent approach is to treat the current outlook as a warning signal rather than a prediction.

“You don’t wait for 100% certainty before you prepare for risks of this magnitude,” Taschetto said. “The sensible response is to use these probabilities to stress-test systems—from water resources and agriculture to health and emergency management—so they’re better able to cope whether El Niño forms or not.”

Whatever happens in the Pacific, researchers say the broader message is the same: in a world where the underlying temperature trend is climbing, the chance that any given year will challenge heat records is now persistently high—with or without help from El Niño.