Ancient Corals Indicate Climate Change Intensifies El Niño Events

A new study in Science used fossilized corals from the Galápagos Islands to compare past and present El Niño events. The evidence shows that recent strong El Niños are significantly more intense than those in earlier centuries. This suggests human-caused climate change is amplifying the natural climate cycle.

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The study’s evidence comes from fossilized coral boulders found on Galápagos beaches, where growth bands record seawater temperature much like tree rings record annual climate. When waters cool, corals substitute strontium for calcium in their skeletons, and oxygen isotope ratios shift with temperature—allowing scientists to reconstruct past ocean conditions over decades-long windows. The Galápagos location is crucial because it sits in the eastern tropical Pacific, the region where El Niño’s warming effects are most pronounced.

Climate models have previously given mixed signals on whether rising global temperatures would strengthen El Niño events. This new physical evidence helps resolve that uncertainty. The current El Niño is predicted to reach three degrees Celsius above normal, exceeding the two-degree threshold typical of strong historical events. Combined with earlier coral records from the western and central Pacific, the findings suggest human