Weather organizations and meteorologists have pointed to the possibility of an El Niño in the Pacific Ocean later this year – a phenomenon that could push global temperatures to an all-time record high in 2027.
The US government’s National Oceanic and Atmospheric Administration (NOAA) and Australia’s Bureau of Meteorology both say some climate models predict El Niño, but both caution that those results come with uncertainty.
Experts told the Guardian it was too early to be sure, but there were signs that the spread of sea surface temperatures in the Pacific could lead to an El Niño in 2026.
The cycle of ocean temperatures in the Pacific is called – El Niño Southern Oscillation (ENSO) – associated with extreme weather events worldwide.
When warmer-than-average waters gather in the eastern equatorial Pacific and extend to the coast of the Americas, it is known as El Niño and is associated with increased global temperatures and dry and hot conditions in Australia.
The An updated southern hemisphere perspective This week from the Australia Bureau said: “Some models suggest the development of El Nino from June.” The bureau warned that it is “too long” to predict El Niño.
NOAA also said “El Nino is likely to increase” but also pointed to uncertainty in the models.
Dr Andrew Watkins, a meteorologist 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. Normally when the trade winds subside it moves back east and warms parts of South America.
“The models are going for that to happen [the Australian] Autumn, it’s pretty much what you expect.
“There are precursors” for El Niño, he said, but it’s too early to tell if the phenomenon will develop.
Associate Professor Andrea Taschetto, an ENSO expert at the University of New South Wales, said the current La Niña – where warm waters are close to Australia – was coming to an end and it was difficult to predict beyond that.
The chances of El Niño developing from June to August or ENSO being neutral are currently about 50/50, or “like a coin toss,” she said.
The past three years have been among the top three warmest years on record for the planet.
El Niño, which formed in mid-2023 and lasted until April 2024, may have added about 0.12C to global temperatures in 2024, said Dr Jake Housefather, a research scientist at the US-based independent Berkeley Earth Research Group.
“If El Nino develops later this year it will peak in November-January and will primarily affect global surface temperatures in 2027 rather than 2026.
“That is why I predict that 2027 will set a new record [for global temperature] If a moderate to strong El Niño event ends up developing.
Watkins acknowledged that if El Nino develops, it will affect global temperatures more strongly in 2027.
“I wouldn’t hesitate to bet against the hottest year on record,” he said.
But global warming from the burning of fossil fuels is now “so strong” that it is “exceeding the year-to-year variability in terms of air temperature,” he said.
“I don’t think we were surprised at all,” he said. “You may not need a strong El Niño to get these warm temperatures.”
