Update: I posed some questions related to this story to Jason Furtado, a meteorologist at the University of Oklahoma. I've added them and Furtado's responses to the end of the post.
In a first, researchers have used chemical fingerprints locked within coral skeletons to build a season-by-season record of El Niño episodes dating back 400 years — a feat many experts regarded as impossible. That record, presented in a new study appearing in the scientific journal Nature Geoscience, reveals an "extraordinary change" in the behavior of El Niño, according to the researchers. That shift "has serious implications for societies and ecosystems around the world."
To conduct their study, lead author Mandy Freund and her colleagues relied on coral records collected by many scientists around the tropical Pacific over the course of decades. The records consists of cores drilled from coral skeletons. As living corals grow, they build their skeletons from compounds drawn from the water, building up bands on a seasonal and even biweekly timescale, much as trees add growth rings every year.
