Coral Records Suggest El Niño Has Strengthened 36%
A 900-year Galápagos coral reconstruction suggests eastern Pacific El Niño variability is about 36% stronger than before industrial warming, including a 16% increase during the past 40 years. The evidence extends beyond short instrument records, although outside scientists dispute whether the corals isolate El Niño from background ocean warming.
A chemical record preserved in living and fossil Galápagos corals suggests that eastern Pacific El Niño swings have become substantially stronger as the planet has warmed. The study extends the climate record back roughly 900 years, far beyond the approximately 75 years covered well by instruments.
The 30-second summary
- What happened? Researchers reconstructed past sea temperatures from coral chemistry and compared the pattern with climate simulations.
- Why does it matter? Stronger El Niño events can intensify drought, flooding, heat, wildfire risk, crop losses and marine disruption around the world.
- What is the catch? Some independent scientists say recent local observations conflict with the reconstruction and may indicate that the corals partly record general warming rather than El Niño alone.
Key Number: The study estimates eastern Pacific El Niño variability is about 36.5% greater than during the preindustrial period, with roughly 16% of that rise occurring in the past 40 years.
How coral became a climate archive
El Niño is the warm phase of the El Niño-Southern Oscillation, or ENSO, a natural cycle that shifts tropical Pacific temperatures and rainfall every few years. Measuring a trend is difficult because events vary sharply and the instrumental record contains only a limited number of the strongest episodes.
The team sampled living colonies and fossil coral boulders around the Galápagos Islands, close to the centre of the eastern Pacific signal. Ratios of strontium to calcium and different oxygen isotopes preserve information about seawater temperature when each layer grew. Uranium-thorium dating establishes the age of older samples. The resulting records cover intervals reaching back to around 1100.
In the Science paper published August 27, 2026, the researchers report that recent variability sits outside the range reconstructed for most of the previous millennium. Climate-model tests indicated that volcanic eruptions and solar changes alone did not reproduce the modern rise, while simulations including human-driven warming did.
Why stronger swings matter
El Niño changes where heat and rain move through the atmosphere and ocean. Its effects differ by region, but strong events can contribute to floods in some places, drought and food shortages in others, warmer global averages and coral bleaching. NOAA had already confirmed the current El Niño in June and expected it to strengthen.
The study concerns the long-term behaviour of ENSO, not the exact outcome of one season. It fits a broader question NewTqnia examined when researchers found that the pace of warming can alter an ocean system’s response. Climate risk depends not only on the average temperature but also on how warming changes natural variability.
Before we overstate the result
The reconstruction is powerful but patchy, using 29 fossil samples and 13 coral records rather than a continuous measurement at every year and location. The Associated Press reports that two outside researchers question the interpretation because recent measured Galápagos temperatures show declining El Niño-related variation. They argue the coral signal may partly reflect background greenhouse warming. The authors say short windows between rare extreme events can conceal the longer trend.
What happens next
Additional coral records from more Pacific locations can test whether the pattern extends beyond one region and better separate mean warming from changing ENSO behaviour. The result does not predict the rainfall or damage from a particular event. It strengthens one line of evidence that the climate cycle itself is changing, while leaving an important measurement dispute open.
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NewTqnia Science Desk
An institutional editorial team within NewTqnia
