An intensifying El Nino broke a temperature record in a key zone of the Pacific in September, the EU’s climate monitor Copernicus said on Monday. Sea surface temperatures in the Nino3.4 monitoring region reached an “all-time high” of 29.70C last month, the service said, adding to signs that the weather pattern is gaining exceptional strength.
Global forecasters have warned for months that this El Nino could become the strongest ever observed. The new record was set before the episode’s expected peak later this year.
What the record means for El Nino’s strength
The reading exceeded the peak temperatures of earlier strong El Nino events in 1982/1983, 1997/1998 and 2015/2016. Copernicus said this underscored “the exceptional intensity of the current El Nino.”
However, the service said it “cannot yet say that the current El Nino is the strongest ever recorded.” It explained that climate change is raising ocean temperatures, which can make recent events look stronger than past ones and complicate historical comparisons.
Copernicus said it had adopted a new index that accounts for the warming of tropical oceans. Under that index, the current event is not yet stronger than past ones. It added that the September values still point to an already exceptionally strong El Nino, particularly because the event has not reached its peak.
Not all forecasters use the same scale. On Friday, Japan’s weather agency said El Nino conditions had reached their “strongest intensity on record,” with temperatures in the monitoring area 4C above normal.
Global ocean and air temperatures hit September highs
As El Nino gathers strength, global average sea surface temperatures reached a record 21.05C for September. That topped the previous high of 20.92C for the same month in 2023, according to Copernicus.
Overall, the world recorded its second hottest September on record, with surface air temperatures averaging 16.27C, the service said. September was 1.63C hotter than the pre-industrial average, defined as the period 1850-1900.
Paris Agreement limit under growing pressure
Nations agreed at the 2015 UN climate talks in Paris to keep global warming “well below” 2C above pre-industrial levels, while pursuing efforts to limit it to 1.5C. In September, the United Nations declared that the long-term 1.5C target would be missed within a matter of years.
Copernicus director Carlo Buontempo said in a statement: “We are in a new run of months above 1.5C, and with a strong El Nino still intensifying it is likely to last into 2027.” He added that crossing the Paris Agreement’s long-term limit “is only a matter of time.”
Scientists say cutting greenhouse gas emissions from fossil fuels is crucial to limit the period of “overshoot” above 1.5C and to bring temperatures back down as quickly as possible.
El Nino warms surface temperatures in the central and eastern equatorial Pacific Ocean, shifting winds, pressure and rainfall patterns worldwide. It typically occurs every two to seven years and lasts around nine to 12 months. Experts have warned that this event would likely push global temperatures to a new record in 2027.
