Subscribe
This summer could be brutal, testing human capacity to cope with heat. The atmosphere is already warming rapidly. The year 2025 was the third-warmest on record, according to the World Meteorological Organization (WMO). January and February this year were the fifth-warmest, says the EU’s Copernicus Climate Change Service. This warming, driven by anthropogenic climate change, could be amplified this summer by a “super” El Niño.
El Niño is the warmer-than-normal phase of the El Niño Southern Oscillation (ENSO), which occurs in the equatorial Pacific Ocean. In an up-date on April 6, Climate Prediction Center (CPC) of the US National Oceanic and Atmospheric Administration (NOAA) put the chance of El Niño developing in June-August at 62 per cent, adding that the event could last until the end of 2026. Similar assessments have come from the EU’s Copernicus service and Australia’s Bureau of Meteorology. “Scientists are telling us that this could be the strongest El Niño event so far this century, comparable to the notable El Niño event in 1998,” says Grahame Madge, senior press officer and climate science communicator at the UK’s Met Office. “‘Super’ El Niño is not a term we subscribe to, but it does underpin the fact that this is likely to be a significant event,” says Madge.
For an El Niño to be declared, sea-surface temperatures in the equatorial Pacific Ocean must be at least 0.5°C above normal, as measured against the Oceanic Niño Index (ONI)—a three-month average of sea-surface temperatures in a small region in the Pacific called Niño 3.4. According to NOAA, an ONI above 0.5°C denotes a weak event; 1.0°C, moderate; 1.5°C, strong; and 2.0°C, very strong. Some climate models suggest the coming episode could exceed 2.0°C by a wide margin, earning the informal “super” label.
Such events are rare. Since 1950 only three very strong El Niños have been recorded—1982–83, 1997–98 and 2015–16—according to a study in Nature Communications in December 2025.
Forecasting, however, remains uncertain. Some scientists, including those at NOAA’s CPC, cite the “spring predictability barrier”. Ocean-atmosphere interactions in the equatorial Pacific Ocean are not very strong during March-May and hence weather models are not able to predict the future of those interactions efficiently. “We typically gain much clearer insight between late May and June...
This article was originally published in the May 1-15, 2026 print edition of Down To Earth