UK Met Office and NOAA forecast intense El Niño as Pacific anomalies reach 2.6°C

Pacific ocean measurements

The UK Met Office and the US National Oceanic and Atmospheric Administration reported on Friday that equatorial Pacific sea temperatures are climbing toward levels unseen in modern meteorological observations. Meteorologists declare an El Niño event when sea surface temperatures in the central and eastern Pacific rise at least 0.5°C above the long-term average. The natural cycle recurs every two to seven years and typically persists between nine and twelve months as trade winds weaken, suppressing the upwelling of cold deep water off South America. Current measurements compiled by the Climate Brink panel from NOAA data show surface temperatures in the Niño 3.4 region are already 2.6°C above the 30-year average. Sub-surface readings collected by the National Weather Service Climate Prediction Center during July showed heat accumulating in deeper ocean layers with anomalies reaching up to 10°C above normal alongside an unusually deep thermocline.

Forecasting models and global temperature records

International climate models indicate a 69% probability that the developing event will surpass all events observed since 1950, based on NOAA calculations using the Relative Oceanic Niño Index. Pacific sea surface anomalies are projected to peak at 3.9°C in November 2026, exceeding the previous peak of approximately 3°C recorded in 2015. Large ocean-warming events transfer large amounts of stored thermal energy into the atmosphere, producing delayed temperature rises across the globe. Dr Nick Dunstone described how the delayed atmospheric warming will affect global averages in the following calendar year.

During large El Nino events significantly more heat is released from the ocean to the atmosphere leading to an increase in global average temperature, particularly in the calendar year following the winter peak of the El Nino.

Met Office scientists project that 2027 will likely replace 2024 as the warmest year on record and temporarily push global temperatures more than 1.5°C above pre-industrial levels.

Regional precipitation shifts and crop risks

The atmospheric disruption changes worldwide wind, air pressure, and rainfall distribution. Forecast models indicate severe droughts across tropical South America, southern Africa, and north-eastern Australia, alongside heightened risks of crop shortfalls and price increases for commodities such as sugar, coffee, and cocoa. Western South America faces heavy rainfall and flood risks. For north-western Europe and the United Kingdom, forecasters project increased storm activity and heavier precipitation starting in November. Professor Adam Scaife described the scale of the long-range forecast data.

I have never seen an El Nino signal this intense in our forecasts.

Infrastructure strains and climate adaptation

The global forecast follows severe summer weather across Europe, where Swiss water bodies fell to low levels during a heatwave with temperatures near 40°C, and the United Kingdom experienced its driest July in 190 years, leaving 71.3% of England and all of Wales in drought. High temperatures placed Britain's transport network under strain, prompting operators to cut train speeds and timetables after two trains derailed within 24 hours during the fifth August heatwave. In response to rising climate risks, Network Rail increased its five-year spending on earthworks, drainage, and climate resilience in 2024 by five times compared to 2019 allocations. University of Warwick ground engineering professor Xueyu Geng noted that while British rail is manufactured to endure winter lows of -10°C, infrastructure design standards must incorporate higher upper boundaries, citing rail systems in Spain that operate up to 45°C and Saudi Arabia up to 55°C.