- 40 per cent stronger: Recent El Niño events are about 40% more intense than in the pre-industrial era.
- 1,000-year warning: No El Niño events in the previous millennium matched the strength seen in recent decades.
- 90 per cent chance: Forecasts give the 2026–27 El Niño a greater than 90% chance of reaching very strong or near-record levels.
- Extreme weather: Stronger El Niño events can worsen droughts, floods, wildfires and food insecurity.
- Global warming link: Researchers say rising temperatures may be “supercharging” El Niño and increasing climate-related damage.
El Niño is the warm phase of the El Niño-Southern Oscillation (ENSO), a natural climate pattern centered in the tropical Pacific Ocean. It occurs when unusually warm ocean surface temperatures develop and can influence weather patterns across much of the world.
Its cooler counterpart is known as La Niña. A typical ENSO cycle lasts between two and seven years, but the intensity of individual El Niño events can vary considerably.
The new study suggests that something unusual is happening: the strongest El Niño events of recent decades appear to be outside the normal range seen over the previous 1,000 years.
Researchers from the University of Michigan and other institutions examined modern and ancient corals from the Galápagos Islands, about 1,000 kilometers off the coast of Ecuador.
Their findings, published in Science, indicate that El Niño events during the past 40 years were about 40 per cent stronger than those during the pre-industrial period.
How did scientists discover this?
Corals act like natural climate archives.
As corals grow, they build layers of calcium carbonate at a rate of roughly one to two centimeters a year. The chemical composition of those layers preserves information about the seawater temperatures surrounding them when they formed.
Scientists collected cores from 13 corals, including living colonies and ancient coral boulders. The samples contained records spanning at least 20 years, allowing researchers to track repeated El Niño events.
The team examined the ratio of strontium to calcium in the coral skeletons, which changes according to temperature. They also studied oxygen isotopes, another indicator of past temperatures.
The records showed a clear difference between recent decades and much of the preceding millennium.
"We don't see a time in the past where El Niños have been as strong as today, and we show that the strength of El Niño changes in parallel with the warming of global temperature," said lead author Julia Cole, professor and chair of the University of Michigan's department of earth and environmental sciences.
"Our findings tell us that the big El Niño events of the last 40 years are not normal in the context of the last thousand years," Cole said.
Researchers also used climate models incorporating factors such as volcanic eruptions and changes in solar activity. Those simulations did not show natural processes producing changes large enough to explain the recent increase in El Niño intensity.
Why does stronger El Niño matter?
El Niño is not simply a change in ocean temperature. Its effects can spread across continents, altering rainfall, temperatures and atmospheric circulation.
A stronger event can mean more severe droughts in some regions and heavier rainfall and flooding in others. It can contribute to wildfire risk, damage infrastructure and threaten food supplies.
"The question is not whether the current El Niño is going to happen, but how bad is it going to be, and how bad will the impacts be?" Cole said.
The concern is particularly serious because El Niño is occurring on top of a warming planet.
"This event is superimposed on global warming, and it's likely to supercharge the temperature increase that we would normally see from greenhouse gases," Cole said.
Global weather and climate agencies have forecast a greater than 90 per cent chance that the 2026–27 El Niño could reach very strong or near-record levels.
Researchers warn that such an event could push global temperatures to around 1.7 or 1.8 degrees Celsius above pre-industrial levels, potentially exceeding the current temperature record.
"El Niño is a really big source of climate extremes, and so if it's getting stronger, the impacts are getting stronger. Impacts like droughts, floods, wildfire and food insecurity," Cole said.
The study's broader warning is stark: if global warming is making El Niño more powerful, future climate extremes could become increasingly difficult and expensive to withstand.
"We believe global warming is supercharging El Niño, and if that's true, then we expect stronger climate extremes that will amplify ecological, infrastructural and human losses," Cole said.
"No country has the resources to be fully protected from these impacts. This is one more reason we need to move away from fossil fuels, the root cause of the problem," she added.
Claude.in
