Sea surface temperatures in a key area of the Pacific used to track El Nino reached a record in September, the European Union’s Copernicus Climate Change Service said on Monday. The monitor said the reading points to an exceptionally strong event that has not yet reached its peak.
Copernicus reported that the Nino3.4 region averaged an all-time high of 29.70C last month, above the peaks recorded during strong El Nino episodes in 1982/83, 1997/98 and 2015/16. Forecasters have warned for months that the current event is likely to be the strongest ever observed, and the record arrived ahead of the peak expected later this year. El Nino is the warm phase of a natural climate cycle that heats the tropical Pacific, raising the risk of drought and floods and adding to human-caused warming.
Copernicus told AFP it “cannot yet say that the current El Nino is the strongest ever recorded”. Rising ocean temperatures can make recent events look stronger than older ones, so the service has adopted a new index that accounts for warming in the tropical ocean, and on that measure the current event does not yet exceed earlier ones. Other agencies use different scales. On Friday, Japan’s weather agency said El Nino had reached its strongest intensity on record, with temperatures in its monitoring area 4C above normal.
Wider ocean and air temperatures were also high. The global average sea surface temperature set a September record of 21.05C, beating the 20.92C recorded in September 2023. September was the world’s second-hottest on record, with surface air temperatures averaging 16.27C, 1.63C above the 1850 to 1900 pre-industrial average. The 2015 Paris Agreement aims to hold warming well below 2C and to pursue a 1.5C limit, and the United Nations said in September that the 1.5C target would be missed within a few years.
Copernicus director Carlo Buontempo said the world has entered a new run of months above 1.5C that is likely to continue into 2027 as El Nino strengthens. “Crossing the Paris Agreement’s long-term limit is only a matter of time,” he said, adding that the scale and duration of any overshoot depend on human action. Experts expect the event to push global temperatures to a new record in 2027. El Nino typically returns every two to seven years and lasts nine to 12 months.
