Super El Niño sets another record as it strengthens to 'unprecedented levels'

Flooded streets following the arrival of Hurricane Polo in the town of Puerto San Carlos, Baja California Sur, Mexico, on 29 SeptemberImage source, AFP via Getty Images
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Flooded streets following the arrival of Hurricane Polo in the town of Puerto San Carlos, Baja California Sur, Mexico, on 29 September. The Category 3 storm added to an already busy hurricane season turbo-charged by El Niño.

BySimon King
Lead Weather Presenter
  • Published

El Niño has continued to strengthen to what some scientists are calling "unprecedented levels", weeks before its expected peak in December.

Several key measures are now in record territory.

In its latest update, Australia's Bureau of Meteorology (BOM) said average weekly sea-surface temperatures in the central Pacific have reached their highest level on record, external.

It comes after scientists declared a new record for daily sea surface temperatures in the central-eastern Pacific in September, exceeding the previous record set during the very strong El Niño of 2015.

Graphic showing the sea surface temperature - compared with 1991-2020 average - for different years. Four mini globes mapping the El Niño region show the warmer than average temperatures for Dec 1972, 1982, 1997 and 2015. A larger globe of the eastern Pacific showing much more red and orange - and therefore warmth for Dec 2026 (forecast)
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El Niño this year is creating new ocean temperature records in a background of overall ocean warming due to human-induced climate change, seen especially when comparing previous record El Niño events

Temperatures above 30C have also been recorded for the first time in parts of the tropical Pacific, while record sea-surface temperature anomalies and exceptional subsurface warmth have been observed.

These measurements come from the region of the equatorial Pacific used to monitor El Niño.

El Niño is a naturally-occurring pattern, which happens about every two to seven years and tends to last for around a year.

However, the Pacific is also warming due to human-induced climate change and this is starting to mask the strength of the natural warming during El Niño.

To remove this additional warming signal, Australian and US official forecasters are now using a Relative Ocean El Niño Index (RONI), to enable better comparison to historical events.

Using that measure, the BOM's average weekly data - while only going back to 2008 - is significant as it now exceeds levels during the record-breaking December of 2015.

"We are currently witnessing an El Niño event that is unprecedented in the historical record," Dr Zeke Hausfather, a climate scientist at Berkeley Earth, told the BBC.

Strong El Niño in a warmer world

The warmth across the Pacific now extends well beyond the tropical region normally used to monitor El Niño.

Comparisons with previous major events in 1972-73, 1982-83, 1997-98 and 2015-16 show much more widespread ocean warmth across the Pacific and into the Gulf of Mexico.

Part of this reflects the long-term warming of the oceans but scientists say it is not the whole story.

"The strength of El Niño this year is spilling out of the traditional El Niño region," Dr Hausfather said.

The World Meteorological Organization (WMO) says there is currently no evidence that climate change is making El Niño events stronger or more frequent, external. However, it remains an active area of scientific research.

What is clearer is that El Niño releases additional heat from the oceans into the atmosphere.

Historically, global temperatures during El Niño years are typically higher than during neutral years.

Combined with human-driven climate change, that extra heat is expected to help make 2026 one of the warmest years on record, with unusually high global temperatures likely to continue into 2027.

No two El Niño events are exactly alike

Torrent of flood waters raging through a settlement with people stranded on the roof of their building surrounded by flood waterImage source, Getty
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The 1997-98 super El Niño brought devastating floods throughout Ecuador

Although the most widespread impacts are expected later this year and into 2027, El Niño's influence is already being felt across parts of the world.

The strength of an El Niño does not automatically determine the scale of impacts in any one location. Regional effects can vary considerably from one event to another.

However, some common patterns are emerging when compared with previous super El Niños.

During the 1997-98 event, severe drought across south-east Asia contributed to extensive peat and forest fires, while parts of East Africa experienced devastating floods.

The event also helped make 1998 the warmest year on record at the time.

A similar pattern developed during the 2015-16 El Niño.

Severe drought and wildfire activity returned to parts of south-east Asia, while southern Africa experienced one of its worst droughts in decades, triggering a major humanitarian crisis.

Another recurring signal is tropical cyclone activity. Strong El Niño events typically suppress Atlantic hurricanes while boosting activity across parts of the Pacific, a pattern that has also been observed during 2026.

The World Meteorological Organisation says drought and flood-related disruption is already being reported in several regions, with growing concerns over food security in parts of East Africa and the Asia-Pacific.

Forecasts from both the European Centre for Medium Range Weather Forecasts and the US National Oceanic and Atmospheric Administration indicate El Niño is likely to peak in December.

Dr Hausfather said the latest projections were "astonishing" and are likely to set new records "by a remarkable amount".

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