Climate scientists are debating the intensity of the current El Niño, with some suggesting it may surpass all previous recorded events.

A developing El Niño in the tropical Pacific is showing record-breaking intensity, according to climate scientist James Hansen. While experts use different metrics to measure the phenomenon, there is consensus that the current event is exceptionally strong and expected to have significant global climate influences throughout 2026.

Disagreement Over Measurement Metrics

James Hansen of Columbia University states that the heat anomaly in the upper 300 meters of the equatorial Pacific has already exceeded the 1997-98 super El Niño. However, Adam Scaife of the UK Met Office notes that the common Niño3.4 index, which measures sea surface temperature, has not yet surpassed the 2.5°C anomaly peak recorded during the 1997/1998 event. Scaife notes the current anomaly is approximately 2°C above the norm. Daniel Swain of the California Institute for Water Resources suggests that the Niño3.4 index is currently at its highest level for this time of year. He argues that using a long-lag running mean can be misleading during rapid climate changes. Despite this, data shows that the daily Niño3.4 value reached nearly 3.1°C in November 2015, meaning the current event has not yet reached that specific historical peak.

Potential for Historic Impact

Experts anticipate that the current El Niño will continue to intensify, with forecasts suggesting it could eventually exceed all previous events. Hayley Fowler of Newcastle University suggests the event may reach or surpass the levels of the 1877-1878 El Niño, which was associated with widespread famine and approximately 50 million deaths globally. Adam Scaife stated that he has never observed an El Niño signal this intense in weather forecasts.