El Niño now strongest in 1,000 years, Galápagos coral study finds

August 31, 2026 at 09:04 PM2 min

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El Niño events in the eastern Pacific are now stronger than at any point in the last 1,000 years, according to a study of fossilized Galápagos corals. The finding suggests recent El Niño activity is unprecedented in the pre-industrial record. Researchers reconstructed ocean temperatures from coral chemistry to reach this conclusion.

Key Facts

The study reconstructed a 1,000-year ocean temperature record using fossilized corals from the Galápagos Islands.
El Niño events in the eastern Pacific are now stronger than at any point in the last 1,000 years.
The research was led by Julie Cole, an environmental scientist at the University of Michigan.
The coral record covers scattered years back to around 1100 CE, based on 28 time-separated series from five islands.
The Galápagos are located at 90 degrees west, and the next island in that near-equatorial zone is at 160 degrees west.

Coral Temperature Record

Cole's team analyzed strontium-to-calcium ratios and oxygen isotopes in coral skeletons, both of which track water temperature. Corals in the Galápagos grow one to two centimeters per year, laying down a calcium carbonate skeleton that records the water chemistry. Sampling extracted cores millimeter by millimeter yields more than a dozen measurements per year, creating a monthly temperature log for each coral colony. Living colonies cover recent decades and were checked against instrument data, while dead coral heads were dated using uranium-thorium methods to within a few years. The result was a patchy but long temperature record spanning scattered years back to around 1100 CE.

Unprecedented El Niño Strength

The reconstructed record shows that El Niño events in the eastern Pacific have never been as violent as they are now. Cole said the recent events "don't look anything like what we see in the pre-industrial era." The last four decades appear unusual when set against the 1,000-year baseline. The study addresses uncertainty about whether global warming is making El Niño swings more dramatic. Instrumental data alone are too short to separate a trend, which motivated the coral reconstruction.