‘Simply staggering’: Rapidly developing ‘super El Niño’ on track to peak in December

El Niño is a naturally occurring climate pattern in the tropical Pacific. It happens when the ocean releases heat into the atmosphere. That temporarily lifts global temperatures and can alter weather far beyond the Pacific. The name “super El Niño” signals an exceptionally powerful event, although the article does not give a formal threshold for that label.

The event’s strength is measured using the Niño3.4 anomaly. This records how much warmer sea surfaces are than average in part of the central Pacific. More than 600 forecasts from 14 climate models project an anomaly of around 4C. That would be more than a degree above the previous record, set in 2015-16.

This event is already exceptional. Its development has been unusually rapid, and its temperatures have stayed above earlier El Niño events since June. Hausfather wrote that it may become the strongest El Niño in the past millennium. Ten of 14 models expect its peak in December.

The central Pacific is expected to become around 4C warmer than average in the Niño3.4 region. This is a sea-surface temperature anomaly, not the temperature of the whole Pacific or the entire planet. It is the main measure used to track El Niño’s strength.

Carbon Brief’s estimate comes from more than 600 forecasts made by 14 climate models. Ten models expect the Niño3.4 anomaly to peak in December, while four expect a November peak. The projected value would exceed the previous El Niño record by more than 1C. That earlier record occurred during 2015-16.

The event has already produced striking measurements. On 18 September, the daily anomaly reached 3.11C, breaking the satellite-era record set in 2015. September’s monthly anomaly was 2.84C, the highest since sea-surface temperature records began in the mid-1800s. The forecast therefore represents further intensification.

El Niño’s peak in the tropical Pacific does not immediately produce its maximum effect on the world’s average temperature. The article explains that global temperatures typically lag warming in the tropical Pacific by around three months. This delay allows the event’s atmospheric influence to spread and affect the global average after the ocean peak.

Carbon Brief’s model analysis finds that 10 of 14 models expect the Niño3.4 region to peak in December. The remaining four models expect a November peak. The event began in June and has already remained well above previous El Niño events, but its strongest global temperature influence is expected later.

That timing makes 2027 especially important. Carbon Brief projects an average global temperature of around 1.74C above pre-industrial levels for 2027. It also calculates a 96% chance that 2027 will be the warmest year on record. The projection includes uncertainty about temperatures during the rest of 2026.

El Niño matters beyond the tropical Pacific because it releases stored ocean heat into the atmosphere. That changes the background conditions influencing weather in distant regions. The article describes this year’s event as already reshaping the world’s weather, showing how a natural Pacific pattern can have global consequences.

Two examples stand out. The event has fuelled fires in Indonesia and contributed to “super typhoons” in the west Pacific. These effects illustrate different ways El Niño can alter regional weather. The article does not provide a detailed explanation for each location, but it links both developments to the ongoing event.

The risks continue as El Niño intensifies. Its Niño3.4 anomaly is projected to peak around 4C in December. Since global temperatures usually respond to tropical Pacific warming with a delay, the event’s strongest influence on the global average is expected in 2027. Its wider weather effects can therefore remain important beyond the Pacific peak.

Carbon Brief calculates a 96% chance that 2027 will be the warmest year on record. Its projection places the year’s average global temperature around 1.74C above pre-industrial levels. This estimate reflects the expected influence of the unusually strong El Niño, not just the Pacific event’s immediate peak.

The key mechanism is timing. El Niño warms the tropical Pacific and releases heat into the atmosphere, while global temperatures generally lag that tropical Pacific warming by around three months. The event is expected to peak in the Niño3.4 region during December 2026, so its greatest effect on the global average is projected for 2027.

The estimate is not presented as certain. Carbon Brief bases it on the historical relationship between year-to-year temperature changes and El Niño conditions during the preceding autumn. It also includes uncertainty about how global temperatures will develop through the rest of 2026. Human greenhouse-gas emissions remain responsible for almost all long-term warming.

The current El Niño is tracking well above the 2015-16 event, which previously held the record for strength. Forecasts from 14 climate models suggest a Niño3.4 anomaly of around 4C. That would be more than 1C higher than the earlier record, making the difference unusually large.

The event has also broken records during its development. On 18 September, the daily Niño3.4 anomaly reached 3.11C, beating the satellite-era record set in 2015. September’s monthly anomaly reached 2.84C, the highest recorded since sea-surface temperature records began in the mid-1800s. Hausfather said it had run above every prior event since June.

The comparison reaches further back than modern measurements. Hausfather wrote that nothing like this had appeared in the historical record and that it may become the strongest El Niño in the past millennium. That remains a possibility, not a confirmed historical ranking. Ten of 14 models expect the event to peak in December.

El Niño and human-caused warming operate on different timescales. El Niño is a natural climate pattern that releases heat from the tropical Pacific Ocean into the atmosphere. It can strongly influence temperatures in particular years. By contrast, the article says human greenhouse-gas emissions are responsible for almost all long-term global warming.

This means natural variation can temporarily amplify the warming trend. During a strong El Niño, extra ocean heat enters the atmosphere, raising the global average above what the longer-term trend alone might produce. The current event has already reached record levels in the Niño3.4 region and is projected to approach a 4C anomaly.

The effect will not end with the Pacific peak. Global temperatures usually lag tropical Pacific warming by around three months, so the largest influence is expected in 2027. Carbon Brief projects about 1.74C above pre-industrial levels that year, while the underlying long-term warming continues because greenhouse-gas emissions remain the dominant cause.