‘Impossible’ research produces 400-year El Niño record, revealing startling changes: Centuries long seasonal record of El Niños from coral cores 

Coral experts around the world said it was impossible to extract a multi-century record of El Niño events. But now a persistent effort has produced the world’s first 400-year long record of El Niño events. And the changes researchers have found to El Niños in recent decades are startling.

Source: ‘Impossible’ research produces 400-year El Niño record, revealing startling changes: Centuries long seasonal record of El Niños from coral cores — ScienceDaily