El Niño could make 2027 hotter than record 2024

A brutal summer of record-breaking heat across the Northern Hemisphere is being driven by climate change, and the developing El Niño event could make 2027 even hotter, according to scientists and climate analysts. Europe experienced its hottest June–July stretch on record, the contiguous US logged its hottest July ever, and South Korea set an all-time high temperature.

The heat has affected millions of people, with Europe battered by repeated heat waves and the US breaking a record that had stood since July 1936, during the Dust Bowl. Climate change is making such heat waves more likely and intense, and Europe is the world's fastest-warming continent, second only to the Arctic in regional warming.

A study of Europe's May heat wave found that a similar event in 1976 would have been about 3.5 °C (6.3 °F) cooler than under today's conditions. The contiguous US July record excludes Alaska and Hawaii, and its fall is concerning because it breaks a mark set during an environmental disaster.

The current El Niño phase, defined by the National Oceanic and Atmospheric Administration as a period when a specific part of the Pacific Ocean is 0.5 °C hotter than usual plus associated atmospheric changes, is expected to be especially strong. Some forecasts predict the event could peak at over 3.5 °C above average, potentially making it the strongest on record, and climate scientist Zeke Hausfather writes in an analysis for Carbon Brief that it represents "one of the fastest onsets in the observational record."

El Niño does not add energy to the climate system but releases heat stored in the oceans into the atmosphere, and its effect on global temperatures tends to lag ocean pattern development by several months. The most recent El Niño developed in 2023 and ran into 2024, and 2024 is the reigning hottest year on record, Hausfather points out. United Nations Secretary-General António Guterres said in a June video statement, "El Niño conditions will pour fuel on the fire of a warming world."

Individuals can prepare by buying air conditioners, installing solar and backup batteries, or upgrading home insulation, but longer-term temperatures will keep climbing because fossil fuel burning continues. Guterres said the only effective response is climate action equal to the crisis, including ending fossil fuel addiction, accelerating renewables, protecting the vulnerable, and delivering early warning systems.