1,000 Years of Coral Records Reveal a Troubling Shift in El Niño Intensity
August 29, 2026
Scientists studying ancient coral from the Galápagos Islands have uncovered new evidence that El Niño events in recent decades have become substantially more intense than those experienced during most of the previous millennium.
The research, published in Science, reconstructs nearly 1,000 years of eastern Pacific climate history using chemical signals preserved inside coral skeletons. Researchers found that El Niño variability during the past 40 years was roughly 37% higher than during the pre-industrial period, with recent events standing out from the historical record.
Ancient coral provides a climate record
Understanding how El Niño changes over centuries is difficult because modern instrumental measurements cover only a relatively short period.
To overcome that limitation, researchers examined both living and ancient corals from the Galápagos region. Coral skeletons preserve chemical information about the seawater surrounding them as they grow. By analyzing those chemical signatures, scientists were able to reconstruct past variations in Pacific Ocean temperatures.
The location was particularly valuable because the eastern Pacific is one of the key regions where El Niño develops.
Recent El Niño events stand out
The researchers compared the reconstructed climate record with modern observations and found a striking difference.
El Niño events during the most recent four decades were stronger and more variable than those recorded in the reconstructed pre-industrial period. The study estimates that eastern Pacific El Niño variability is approximately 36.5% stronger than its pre-industrial level.
The researchers also found that much of the increase occurred during the modern period, particularly after the late 20th century.
This pattern is important because scientists have long debated how global warming could affect the naturally occurring El Niño-Southern Oscillation, or ENSO.
What is El Niño?
El Niño is a recurring climate phenomenon involving unusual warming of surface waters across parts of the tropical Pacific Ocean.
Normally, trade winds push warm surface water toward the western Pacific. During an El Niño episode, those winds weaken and warm water shifts eastward. The resulting changes in the ocean and atmosphere can influence weather patterns thousands of miles away.
A strong El Niño can contribute to flooding, drought, heatwaves, wildfires and agricultural disruption in different parts of the world.
Climate change may be amplifying the phenomenon
The new research adds evidence to the argument that human-caused warming is affecting the intensity of El Niño.
Researchers compared their reconstructed record with climate simulations designed to account for natural influences. The modern increase was difficult to reproduce using natural factors alone, while the observed pattern corresponded with a warming climate.
Scientists emphasize, however, that the relationship between global warming and ENSO remains complex. The study provides evidence of a significant change in El Niño behavior but does not mean that every future El Niño will automatically become stronger.
Potential consequences around the world
A more variable or intense El Niño could increase the risk of extreme weather in regions that are already vulnerable to climate-related disruptions.
Changes associated with El Niño can affect rainfall, water supplies, crop production, wildfire conditions and marine ecosystems. The effects differ from one region to another, meaning that a strong event can produce severe drought in one location while increasing rainfall and flooding elsewhere.
For countries dependent heavily on predictable monsoon and agricultural conditions, changes in Pacific climate patterns can have particularly important consequences.
Scientists say preparation will become increasingly important
The findings highlight the importance of improving climate monitoring and forecasting systems.
Better understanding of long-term ENSO behavior could help governments, farmers, water managers and disaster-response agencies prepare for extreme conditions before they arrive.
At the same time, scientists stress that coral records are primarily a window into the past. They can reveal how the climate system behaved over centuries, but they cannot provide certainty about exactly how future El Niño events will evolve.
The new evidence nevertheless adds an important piece to the scientific picture: the strongest and most variable El Niño behavior of recent decades appears unusual when viewed against a roughly 1,000-year climate record.
As global temperatures continue to rise, understanding this interaction between planetary warming and Pacific Ocean dynamics could become increasingly important for predicting future climate risks.
