Climate Change Has Made El Niño Events Nearly 40% Stronger, Study Finds
Climate change is intensifying El Niño events, making the natural climate pattern stronger and potentially more dangerous, scientists have warned.
A new study suggests that El Niño events have become nearly 40% stronger over the past 40 years than they were before the Industrial Revolution. The findings indicate that rising global temperatures may be amplifying one of the world’s most influential climate patterns.
The study comes as scientists continue to monitor unusually warm ocean conditions and the possibility of future extreme El Niño events. El Niño raises global temperatures by transferring heat from the Pacific Ocean into the atmosphere, adding to the warming caused by greenhouse gas emissions.
“At no other time in history has El Niño been as strong as it is today. We show that the strength of El Niño changes in parallel with rising global temperatures,” said the study’s lead author, Julia Cole, a professor and chair of the Department of Earth and Environmental Sciences at the University of Michigan, in a statement. “Our findings show that the large-scale El Niño events of the past 40 years are not normal compared with conditions over the past 1,000 years.”
What is El Niño?
El Niño is the warm phase of the El Niño-Southern Oscillation, or ENSO, a natural climate cycle in the tropical Pacific Ocean. The cycle typically shifts every two to seven years between warmer El Niño conditions, cooler La Niña conditions and neutral phases.
During an El Niño event, sea surface temperatures increase in the central and eastern Pacific Ocean. The warming can weaken or reverse the trade winds and disrupt global temperatures, rainfall and weather patterns.
The most recent El Niño event lasted from June 2023 to April 2024 and released large amounts of stored ocean heat into the atmosphere. Combined with long-term global warming, this helped make 2024 the hottest year on record at the time.
Strong El Niño events can have far-reaching consequences, including food shortages and famine, social instability, droughts, floods and wildfires in different parts of the world.
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Coral records reveal a millennium of El Niño activity
Scientists have long suspected that global warming is contributing to more intense El Niño events. However, confirming the connection has been difficult because reliable instrumental records cover only a relatively short period, while natural climate variability can be substantial.
For the new study, published Aug. 27 in the journal Science, researchers examined 13 ancient and modern coral samples collected near the Galápagos Islands, close to the eastern Pacific region where El Niño develops.
Some coral colonies can live for thousands of years, providing scientists with a window into ancient climate conditions.
(Image credit: Greg Asner)
Corals record changes in ocean temperature through the chemistry of their skeletons. By analyzing these temperature-sensitive chemical signatures, the researchers reconstructed El Niño activity over the past 1,000 years.
The coral record showed that relatively moderate El Niño events gradually gave way to stronger events after humans began widely burning fossil fuels in the 19th century. Climate simulations helped the team rule out natural factors, including volcanic eruptions and changes in solar activity, as the primary cause of the recent shift.
“We kept adding records, thinking the story would become more complicated, but it didn’t,” Cole said. “This is a very clear story.”
Why stronger El Niño events are a concern
The interaction between El Niño and climate change is especially concerning because each can intensify the effects of the other. A stronger El Niño can temporarily increase global temperatures, while a warmer atmosphere and ocean may help produce more severe El Niño conditions.
Scientists are also concerned about the potential for lasting changes to major ecosystems, including the Amazon rainforest. More intense El Niño events can increase the risk of drought, heat, wildfire and ecosystem disruption across vulnerable regions.
“El Niño is a major contributor to extreme weather events, and the stronger the El Niño, the greater the impacts, including droughts, floods, wildfires and food insecurity,” Cole said.
In the short term, the combination of climate change and El Niño could place additional strain on a planet already experiencing record heat, water shortages and growing pressure on food systems.
“The question is not whether the current El Niño event will occur, but how severe it will be and how severe its effects will be,” Cole said. “This event coincides with global warming and could further accelerate the normal temperature increase caused by greenhouse gases.”
The researchers said the findings highlight the urgent need to reduce greenhouse gas emissions and limit further global warming.
“No country has the resources to be completely protected from these impacts, which is another reason we need to move away from fossil fuels, which are the root cause of the problem,” Cole said.
Cole, J., Thompson, D., Dies, K., Tripp, C., Tudhope, A., Loverstrom, M., Stevenson, S., Okun, J., Roman, A., Conroy, J., Overpeck, J., Jimenez, G., Edwards, L. (2026). The recent strengthening of eastern Pacific ENSO is unprecedented in the past millennium of paleorecords. Science. Read the study
Source: www.livescience.com