Yahoo News What is El Nino and why is 2025 likely to be colder than 2024?
This year is now almost certain to exceed 1.5C above pre-industrial levels for the first time – but next year is set to be slightly cooler.
While 2024 will almost certainly be the hottest year on record, meteorologists are already predicting that 2025 could actually be slightly cooler.
Global temperatures for 2023 and 2024 were at record highs in part due to the meteorological phenomenon of El Niño. However, the natural climate pattern subsided earlier this year – meaning that temperatures are set to dip slightly in 2025, according to the Met Office.
However, the effects of climate change will still be keenly felt, with the coming year still set to be among the three warmest on record - just behind 2024 and 2023.
In fact, the average global temperature for 2025 is forecast to be between 1.29C and 1.53C, with a central estimate of 1.41C above the average for the pre-industrial period (1850-1900).
This would make 2024 the 12th year in succession that temperatures will have reached at least 1C above pre-industrial levels.
The 1.5C barrier that was broken this year for the first time is seen as an important symbolic moment: a key point beyond which extreme weather, flooding, sea level rises and other negative outcomes are more likely.
The 2015 Paris Agreement aimed to limit global warming to below 1.5C.
The Met Office’s Dr Nick Dunstone, said: “A year ago our forecast for 2024 highlighted the first chance of exceeding 1.5C. Although this appears to have happened, it’s important to recognise that a temporary exceedance of 1.5C doesn’t mean a breach of the Paris Agreement. But the first year above 1.5C is certainly a sobering milestone in climate history.”
But while next year is set to be cooler, the reason has nothing to do with a dip in climate change, but rather to do with ocean cycles in the Pacific.
Why could 2025 be cooler than this year?
Global temperatures for 2024 and 2023 have been elevated slightly by a process of natural climate variation known as El Niño, where warmth from the tropical Pacific warms the global atmosphere.
Sea-surface temperatures have also been warmer than average across much of the world’s oceans.
The Met Office’s Professor Adam Scaife said: “Interestingly, the warm 2025 predicted global temperatures occur despite the tropical Pacific moving towards a La Niña phase which is driving slightly cooler conditions.
“Years, such as 2025, which aren’t dominated by the warming influence of El Niño, should be cooler. 2016 was an El Niño year and at the time it was the warmest year on record for global temperature. In comparison to our forecast for 2025 though, 2016 is now looking decidedly cool.”
What is El Niño?
El Niño is an event where temperatures in the Pacific are warmer than normal – it’s declared when temperatures rise 0.5C above the long-term average.
El Niño and La Niña, the warm and cool phases of a recurring climate pattern across the tropical Pacific, affect weather and ocean conditions around the world, and broadly speaking have opposite effects on the world’ climate.
El Niño events can have knock-on effects on weather in the UK – with El Niño years linked to a risk of colder winters in Britain.
The Met Office says, ‘El Niño is felt strongly in the tropical eastern Pacific with warmer than average weather.
‘The effects of El Niño often peak during December; it's name "the boy" is thought to have originated as "El Niño de Navidad" centuries ago when Peruvian fishermen named the weather phenomenon after the newborn Christ.’
Temperatures around the world increase by about 0.2C during El Niño, and fall about 0.2C during La Niña.
Prof Scaife concluded: “The 2023/24 El Niño event has temporarily provided a boost to global temperature, adding a peak to the rising temperatures driven by years of increasing greenhouse gas emissions.
"However, climate researchers are also actively looking at other factors responsible for driving the extra surge in temperatures.”
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