2026 El Niño forecast to be strongest on record by wide margin

A rapidly intensifying El Niño — forecast to be the strongest since modern record-keeping began — is reshaping expectations for global temperatures, with climate scientist Zeke Hausfather estimating a 35% chance that 2026 will set a new annual heat record and a 92% probability that 2027 will become the warmest year in human history.threads+2

A Historic Climate Event Takes Shape

The National Oceanic and Atmospheric Administration declared El Niño conditions in June and, in its July update, said there is an 81% chance the event will reach "very strong" intensity by autumn — a classification achieved by only seven El Niño episodes in the past 75 years. Hausfather's analysis of 667 ensemble members across 14 seasonal forecast models found that the multi-model median for peak warming in the Niño 3.4 region of the tropical Pacific stands at 3.6°C above normal, roughly 0.8°C hotter than the previous record set during the 2015–16 event. Around 91% of those model runs exceed the prior record at their projected peak.theclimatebrink+2

"This year's El Niño is not only very likely to be the strongest event since reliable records began — it may end up the strongest by a truly mind-blowing margin," Hausfather wrote in his July 12 analysis. Wired reported that if current forecasts hold, cumulative global economic losses from the event could reach approximately $10 trillion by 2032, based on research from Dartmouth College.wired+1

2026 Already Among the Warmest Years

Carbon Brief's earlier state-of-the-climate report found that the first three months of 2026 were the fourth-warmest on record, trailing only 2024, 2025, and 2016. At that point, the outlet estimated a 19% chance of 2026 breaking the annual record. The rapid strengthening of El Niño has since nearly doubled those odds. The World Meteorological Organization warned in May that there is an 86% chance at least one year between 2026 and 2030 will surpass 2024 as the warmest on record.carbonbrief+1

Europe's Deadly Summer

The warming backdrop has already proven lethal. A prolonged heatwave that began in late May and intensified through June shattered temperature records across at least 13 European countries. According to Reuters, EuroMOMO data showed more than 10,000 excess deaths during the late-June peak alone, with over 9,000 among people aged 65 and above. Germany's public health institute reported approximately 5,120 heat-related deaths, while France, Spain, the Netherlands, and Belgium each recorded hundreds to thousands more. The EU's Copernicus Climate Change Service confirmed June 2026 as the hottest June on record for the bloc.reuters+2

With El Niño expected to persist through early spring 2027 at a 97% probability, climate scientists warn the worst of its global temperature impact lies ahead.usatoday+1