A powerful El Niño is already gripping the tropical Pacific — and the World Meteorological Organization (WMO) warns it is on track to become a “very strong” event in the months ahead.
Such a surge in Pacific warming can rapidly redraw global weather patterns, raising the odds of flooding in some regions, drought in others and an added burden of extreme heat.
The WMO says the coming months are likely to bring above-normal temperatures across almost all land areas.
Forecasting centres cited by the WMO place the probability of El Niño lasting through February 2027 at nearly 100%, an unusually high level of confidence.
The agency says it is the first time an El Niño/La Niña update has been delivered in such unequivocal terms.
The warming is expected to build through the autumn and reach its peak towards the end of 2026, with knock-on climatic effects likely to persist well into 2027.
Professor Adam Scaife, the UK Met Office’s Head of Long-Range Forecasting, said the developing episode could be the biggest El Niño in living memory and potentially the most significant since the 19th century.
He added that 2027 is “very likely” to overtake 2024 as the warmest year ever recorded.
El Niño brings an increased risk of floods, drought and extreme heat (stock pic)
While a very strong El Niño is known for triggering major shifts in atmospheric circulation — altering rainfall and temperatures worldwide — the impacts can differ sharply from one location to another.
Some areas may escape extreme conditions altogether, and its influence on Ireland and Europe remains far less predictable.
El Niño most often crests between November and February, but its effect on the global average temperature can linger beyond that window and is often most pronounced in the year after the event takes shape.
The WMO says the Pacific’s surface warming already underway is exceptional, with average temperatures climbing as much as 2.6°C above normal in recent weeks.
More dramatic still is the heat banked below the ocean surface: in July and early August, some areas held temperatures more than 8°C above average.
That vast reserve of excess heat, the WMO says, helps explain why it is so confident the El Niño will continue to strengthen.
In response, the WMO is launching an unusually large international early-warning and preparedness push, working alongside national meteorological agencies, UN organisations and humanitarian groups.
Its concerns span agriculture, food security, water supplies, health and energy systems, as well as the humanitarian toll that can follow floods, drought and extreme heat.
The WMO emphasises that El Niño is a naturally occurring climate phenomenon and is not caused by human-induced climate change.
However, it notes that this event is unfolding on a planet that is already significantly warmer, with oceans that are unusually warm.
