El Niño Events Now Strongest in 1,000 Years as Climate Change Supercharges the Pacific Ocean Pattern

A study published in the journal Science has found that El Niño events over the last 40 years have been substantially more intense than any recorded in the previous 1,000 years, providing strong evidence that human-caused climate change is supercharging the natural Pacific Ocean climate pattern. Researchers from the University of Michigan reconstructed a millennium of El Niño activity by analyzing chemical signatures in coral cores taken from the Galápagos Islands.

Corals grow one to two centimeters per year by secreting layers of calcium carbonate, and the chemical composition of those layers preserves a record of the sea surface temperature at the time each layer formed. By sampling 13 corals, both living and long-dead, researchers were able to piece together a continuous record of El Niño intensity stretching back roughly 1,000 years, well before humans began significantly altering the climate with greenhouse gas emissions around 1850.

The analysis found that El Niño events over the past four decades have been nearly 40% stronger than the average of the preceding centuries. Critically, climate simulations that accounted only for natural drivers like volcanic eruptions and solar variability failed to reproduce this intensification, while simulations that included human-caused warming did - a pattern researchers describe as compelling evidence that greenhouse gas emissions, not natural variability, are behind the trend.