Met Office Forecasts Strongest El Niño Since 1800s

El Niño is a natural pattern that occurs roughly every two to seven years and lasts about a year. Trade winds that normally blow east to west across the Pacific weaken or even reverse, allowing warm water to spread eastwards; heat then escapes from the ocean into the atmosphere, lifting global temperatures and shifting rainfall. This time the deeper ocean is also unusually warm, about 8C above normal at 100 metres (330 feet) deep in places, supplying a reservoir of fuel. Dr Zeke Hausfather, a climate scientist at Berkeley Earth, a United States research group, said the months of development still ahead had raised confidence that this would be a record-setting event. Some groups project as much as 4C above average, which Hausfather said could make it the strongest El Niño in 500 or even 1,000 years, though records cannot reach that far back.

The effects are already visible. India's southwest monsoon is running well below normal, and the Atlantic has produced only three named storms this season. The Met Office says that, combined with human-caused climate change, the event makes 2027 "very likely" to replace 2024 as the warmest year on record. Britain faces a greater risk of a wet, stormy autumn, while Australia may see drought and Peru, Ecuador and the southern United States face flooding. The forecasting service OpenSnow predicts above-average snowfall across California and Nevada, though the last super El Niño, in 2015-2016, finished near seasonal averages around Lake Tahoe.