evidence: With the climate pattern known as El Niño in full force from mid-2023 to mid-2024, global temperatures broke records for 12 months in a row. As one of the strongest El Niño events on record, it was likely the main culprit of unprecedented heat, floods and droughts worldwide. [...] During an extreme El Niño, the impacts on global weather tend to be more severe. For example, during the winter of 1997-98, El Niño brought record rainfall to California, causing devastating landslides that killed more than a dozen people. Over the same period, the planet lost about 15% of its coral reefs due to prolonged warming. [...] The team validated the model by comparing the simulated data with past ocean temperature data retrieved from fossilized shells of foraminifera, a group of single-celled organisms ubiquitous in the oceans long before human existence. By analyzing the type of oxygen compounds preserved in these fossilized shells, the team reconstructed how El Niño drove ocean temperature fluctuations across the Pacific Ocean for the past 21,000 years. The ancient record aligned with the model’s simulations.