Chance of El Niño forming in Pacific Ocean may push global temperatures to record highs in 2027 | El Niño southern oscillation
Weather agencies and climate scientists have highlighted the possibility of an El Niño forming in the Pacific Ocean later this year – one that could push global temperatures to record highs in 2027.
The US government’s National Oceanic and Atmospheric Administration (NOAA) and the Australian Bureau of Meteorology said some climate models predicted an El Niño, but they both cautioned there were uncertainties in those results.
Experts told the Guardian it was too early to be sure, but there were signals in the spread of sea surface temperatures in the Pacific that suggested an El Niño could form in 2026.
The cycle of Pacific ocean temperatures – known as the El Niño Southern Oscillation (ENSO) – is linked to extreme weather events around the world.
When warmer than average waters gather in the eastern equatorial Pacific and extend to the coasts of the American continent, it is known as El Niño and this tends to increase global temperatures and, in Australia, this can be linked to drier and warmer conditions.
The latest southern hemisphere outlook from the Australian office this week said: “Some models suggest the possibility of an El Niño phenomenon from June onwards. The bureau warned that this was a “very long time frame” to predict an El Niño event.
NOAA also said “there is an increasing chance that El Niño will occur” but also noted model uncertainty.
Dr Andrew Watkins, a climatologist at Monash University and former head of long-range forecasting at the bureau, said: “We have a lot of warm water stored in the western tropical Pacific. Typically when the trade winds subside, they move back east and warm areas off South America.”
“The models want this to happen [the Australian] fall, which is about what you’d expect.
He said “the precursors are there” for an El Niño phenomenon, but that it was too early to say whether the phenomenon would develop.
Associate Professor Andrea Taschetto, an ENSO expert at the University of New South Wales, said the current La Niña – where warmer waters are closer to Australia – was coming to an end and it was difficult to predict beyond it.
She said the chances of an El Niño developing, or a neutral ENSO, between June and August were currently about 50/50, or “like flipping a coin.”
The last three years have each been among the three hottest years on record on the planet.
Dr Zeke Hausfather, a researcher at independent US-based research group Berkeley Earth, said an El Niño that formed in mid-2023 and lasted until around April 2024 was likely to add around 0.12°C to global temperatures in 2024.
“If El Niño develops later this year, it will likely peak around November-January and impact global surface temperatures primarily in 2027, rather than 2026.
“That’s why I predicted that 2027 would likely set a new record. [for global temperature] if a moderate to strong El Niño eventually develops.
Watkins agreed that if an El Niño developed, it would have a stronger impact on global temperatures in 2027.
“I would be hesitant to bet against a warmest year on record,” he said.
But he said global warming caused mainly by burning fossil fuels was now “so strong” that it was “simply exceeding annual variability in terms of air temperature”.
“I don’t think anything will surprise us anymore,” he said. “You may not need a strong El Niño to get these warmer temperatures.”
