The intensifying El Niño weather phenomenon reached a new temperature milestone in September, setting a record in a critical section of the Pacific Ocean, according to the European Union’s climate monitoring service.
The development signals the growing strength of the climate pattern, which scientists fear could drive global temperatures even higher in the coming months.
Climate experts have warned that the ongoing El Niño could become the strongest ever recorded. The latest temperature record was established before the phenomenon is expected to reach its peak later this year, raising concerns about its potential effects on weather conditions worldwide.
El Niño is a naturally occurring climate phenomenon characterised by unusually warm sea surface temperatures across the tropical Pacific Ocean. It alters atmospheric circulation and rainfall patterns, increasing the likelihood of droughts and floods in different parts of the world. The phenomenon can also intensify the effects of human-induced global warming by adding to the heat already accumulating in the climate system.
According to the Copernicus Climate Change Service, sea surface temperatures in the Niño3.4 region, a key area used to monitor El Niño activity, climbed to an unprecedented 29.70C in September. The reading surpassed the peak temperatures recorded during three major El Niño episodes in 1982/1983, 1997/1998 and 2015/2016, “underscoring the exceptional intensity of the current El Niño”, the EU climate monitor said.
Despite the new record, Copernicus cautioned against declaring the current episode the strongest in recorded history. In a statement to AFP, the agency said it “cannot yet say that the current El Niño is the strongest ever recorded”. Rising ocean temperatures driven by climate change have complicated comparisons between recent weather events and those observed in previous decades.
To address this challenge, Copernicus has introduced a revised index that takes the warming of tropical oceans into account when assessing the strength of El Niño events. Based on this adjusted measurement, the current episode has not yet surpassed earlier events in intensity. Nevertheless, the agency told AFP that the September readings “point to an already exceptionally strong El Niño, especially given that the event has not yet reached its peak”.
Differences in how meteorological agencies measure the phenomenon have also produced varying assessments of its strength. Japan’s weather agency said on Friday that El Niño conditions had reached their “strongest intensity on record”, reporting that temperatures in the designated monitoring region were 4C above normal.
Record Ocean Temperatures
The strengthening El Niño coincided with another milestone in global ocean warming, as average sea surface temperatures worldwide reached 21.05C in September. The figure exceeded the previous September record of 20.92C, established in 2023, according to Copernicus.
The EU’s climate service also reported that September ranked as the second-hottest month of its kind on record globally. Average surface air temperatures reached 16.27C, placing the month 1.63C above the pre-industrial baseline, which covers the period from 1850 to 1900.
Under the 2015 Paris climate agreement, countries committed to keeping global warming “well below” 2C above pre-industrial levels while pursuing efforts to restrict the increase to 1.5C. The international agreement aims to reduce the risks and consequences associated with climate change.
However, the United Nations warned in September that the world was on course to exceed the long-term 1.5C warming threshold within the coming years. The warning highlights the growing difficulty of meeting international climate goals as greenhouse gas emissions continue to contribute to rising temperatures.
Carlo Buontempo, director of the Copernicus Climate Change Service, said the combination of elevated global temperatures and a strengthening El Niño could prolong the period during which warming exceeds the 1.5C threshold. “We are in a new run of months above 1.5C, and with a strong El Niño still intensifying it is likely to last into 2027,” he said in a statement.
Buontempo also stressed that the extent and duration of the overshoot would depend on future climate action. He added: “Crossing the Paris Agreement’s long-term limit is only a matter of time. How far we overshoot, and for how long, is still up to us.”
Scientists have emphasised that rapidly cutting greenhouse gas emissions, particularly those produced by burning fossil fuels, remains essential to limiting the duration of warming beyond 1.5C. They say reducing emissions could help limit the scale of the overshoot and enable global temperatures to return to lower levels as quickly as possible.
Climate specialists have also warned that the current El Niño could push global temperatures to a new annual record in 2027, as its effects combine with the longer-term warming trend caused by human activities.
The phenomenon develops when sea surface temperatures rise above normal across the central and eastern equatorial Pacific, disrupting prevailing winds, atmospheric pressure and rainfall patterns around the world. El Niño events generally occur every two to seven years and typically persist for nine to 12 months, although their intensity and wider effects vary from one episode to another.
