One in every two El Nino events could be extreme by 2050 if current trends in greenhouse gas emissions continue, a new study has found.
El Nino, a weather pattern known for triggering warmer extremes like heatwaves and floods, could intensify with rising sea surface temperatures, while its counterpart La Nina leads to cooling effects. Both are phases of the El Nino-Southern Oscillation (ENSO) climate driver.
Multiple studies have provided evidence that a consistently warming climate favours more frequent and intense El Nino events, which are known to fuel extreme weather events.
This study, conducted by researchers including those from the University of Colorado Boulder, US, used computer models to stimulate El Nino events over the past 21,000 years—the peak of Earth's last Ice Age, one of the planet's coldest periods.
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It was found that as the Earth's climate warmed since then, El Nino events increasingly became more frequent and intense.
The model also says that if greenhouse emissions continue at current rates, by 2050, one in every two El Nino events could be extreme.
"The highest (ENSO) variability occurs in response to greenhouse warming, with one in two events reaching extreme amplitude," the authors said in the study published in the journal Nature.
An increased ENSO variability signals higher levels of human-induced global warming.
The study's findings mean a relatively lesser time for people to recover, along with increased impacts to life and property, according to lead author Pedro DiNezio, an associate professor at the University of Colorado Boulder.
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"If these extreme events become more frequent, society may not have enough time to recover, rebuild, and adapt before the next El Nino strikes. The consequences would be devastating," DiNezio said.
The most recent 2023-24 El Nino has already been linked to global temperatures breaking records for 12 straight months, starting June last year. The climate driver is thought to have played a major role behind this summer's record-breaking temperatures registered across India, especially in the north.
The study's model was validated against data from fossils of Foraminifera, ocean-dwelling single-celled organisms that existed long before humans.
Analysis of preserved oxygen in these fossils, the team reconstructed how El Niño drove changes in temperatures across the Pacific Ocean for the past 21,000 years.
The World Meteorological Organisation has described the 2023–24 El Nino as one of the five strongest ones on record, causing widespread natural disasters, including heatwaves, floods, and wildfires. It also said that 2023 was Earth's hottest year since records began.
Currently, neutral conditions are said to be prevailing before La Nina is expected to set in later this year, according to the United Nation's weather and climate agency.
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