UN Climate Agency Warns of Potentially Strongest El Niño on Record

El Niño could be the strongest since records began four decades ago, the United Nations' climate agency has warned, with the UN chief warning the world is in the "danger zone of extreme weather".

The naturally occurring weather phenomenon is set to become "very strong" in the months ahead and is near certain to persist through to February, the World Meteorological Organization (WMO) said Thursday.

El Niño warms surface temperatures in the central and eastern equatorial Pacific Ocean, bringing worldwide changes in winds, pressure and rainfall patterns.

El Niño will peak towards the end of this year — though its knock-on impacts for the climate will continue well into 2027, said the WMO.

Heat in the oceans releases more slowly into the atmosphere, pushing up global temperatures the following year.

The powerful 2023-24 El Niño contributed to 2024 being the warmest year on record, and "we should not be surprised if this record is broken", Ms Saulo added.

"El Niño is firmly established and will intensify into a very strong event in the coming months, with big impacts on rainfall and temperature patterns and associated risks of floods, drought and extreme heat," the WMO said.

El Niño is a natural climate phenomenon and is not caused by climate change.

But scientists expect it will exacerbate the heat of a planet already warming from burning fossil fuels, while amping up weather extremes.

"The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up. Sea surface temperatures are rising, temperatures keep climbing, and the world is in the danger zone of extreme weather," he said.

'Massive blow' to economies

"This exceptional El Niño … has the potential to deliver a massive blow to communities and economies across the world", said Ms Saulo.

She put disaster management authorities and climate-sensitive sectors like agriculture, health, energy and water on notice, saying there was "no time to lose" in getting ready.

El Niño typically takes place every two to seven years and lasts about nine to 12 months.

Conditions oscillate between El Niño and its opposite La Niña, with neutral conditions in between.

"Fuelled by exceptionally warm ocean conditions across the tropical Pacific, El Niño is expected to strengthen further during the coming months to a very strong intensity," the WMO said.

The UN agency classifies El Niño events as weak, moderate, strong or very strong, meaning it is set to reach the highest level out of four.

The WMO said there was an "exceptionally high likelihood of nearly 100 per cent" that El Niño will continue through to February.

Pacific Ocean heating up

El Niño can reshape weather and climate patterns thousands of kilometres away from the tropical Pacific.

Every El Niño is different, but major events often follow familiar patterns.

This includes drought across parts of the Amazon, Indonesia and Australia, disrupted monsoons in India, and shifting rainfall throughout the tropics.

For September-November, WMO forecasts indicate an increased likelihood of above-normal temperatures "across almost all land areas", alongside rainfall patterns showing a "pronounced and classic atmospheric response to the strong Pacific El Niño", the UN's weather and climate agency said.

The index, which measures sea surface temperature anomalies in the central eastern equatorial Pacific, has strengthened from an average 1.5C above normal between May and July.

Weekly values between late July and mid-August ranged from around 2.2C to 2.6C above average, indicating continued El Niño intensification.

In some areas, subsurface ocean temperatures were more than 8C above average during July and early August.