UK Met Office forecasts strongest El Nino in a century; 2027 likely hottest year

The British Met Office has forecast that the ongoing El Nino weather pattern is set to become the strongest in over a century, with potential implications for global temperatures and extreme weather events. The agency said on Friday that sea surface temperatures in the tropical eastern Pacific are expected to rise more than 3 degrees Celsius above normal in the coming months.

El Nino is a natural climate phenomenon characterised by warming of ocean waters in the central and eastern tropical Pacific. It triggers changes in wind patterns, atmospheric pressure, and rainfall across the globe, and typically leads to higher global average temperatures.

Adam Scaife, head of long-range forecasting at the Met Office, described the event as "unprecedented" in modern records. "We are expecting the biggest El Nino for over a century, peaking at something over three degrees — that is unheard of in modern climate records," he told the BBC.

According to the Met Office, an El Nino is declared when water temperatures rise at least 0.5 degrees Celsius above the baseline. While the phenomenon is part of a natural cycle, scientists say climate change amplifies its impacts, adding stress to already warming global systems.

Data from the Climate Brink dashboard, based on U.S. National Oceanic and Atmospheric Administration figures, indicate Pacific temperatures are currently about 2.6 degrees Celsius above the 30-year rolling average. Forecasts suggest the anomaly could peak at 3.9 degrees Celsius this November, exceeding the previous high of around 3 degrees Celsius recorded in 2015.

Scaife, who specialises in climate modelling, said he had never seen such an intense El Nino signal in the agency's forecasts. "We should be clear that this is an unprecedented event," he wrote in a Met Office blog. He added that even a 2-degree rise would normally be considered a "really big event".

The Met Office warned that a record El Nino would compound the effects of climate change, following a summer marked by heatwaves across Europe. The phenomenon typically brings drier conditions to Southeast Asia, Australia, southern Africa, and northern Brazil, while increasing rainfall in the Horn of Africa, the southern United States, Peru, and Ecuador.

Scaife said the anomalous warmth would have particularly strong effects in the tropics, with "really severe droughts" expected in parts of South America and the West Pacific. The Met Office noted that El Nino is already causing below-normal rainfall in India. In the United Kingdom, the event is expected to bring increased rainfall and storminess around November.

"These are not short-term weather forecasts. We're talking about really long-term, persistent conditions here," Scaife stressed.

Looking ahead, the Met Office's Nick Dunstone said 2027 is now "very likely to replace 2024 as the warmest year on record". In 2024, global temperatures exceeded the 1.5 degrees Celsius threshold above pre-industrial levels, a target set under international climate commitments. Last year was the third hottest on record.

The British forecast aligns with other projections. Carlo Buontempo, director of the European Union's Copernicus Climate Change Service, said earlier this year that 2026 could be another record-breaking year.

The term "El Nino", Spanish for "the boy" or "the Christ Child", was coined by Peruvian and Ecuadoran fishermen in the 19th century to describe the arrival of an unusually warm ocean current before Christmas. The phenomenon alternates irregularly with its cooling counterpart, La Nina, in a cycle that has persisted for thousands of years.