The current El Niño could become the strongest ever, according the World Meteorological Organization – but are El Niños in general getting stronger due to climate change? New evidence suggests.. maybe.
The Pacific El Niño–Southern Oscillation (ENSO) generates climate extremes that endanger ecosystems, infrastructure, and human well-being worldwide. The response of this system to climate warming is poorly constrained, due both to data scarcity and uncertainties in climate models. The geochemistry of Galápagos coral skeletons across the past millennium reveals a large recent increase in interannual variability of sea surface temperature in the eastern equatorial Pacific compared to existing paleorecords that exceeds simulated natural variability. This increase parallels rising global temperature and results from stronger El Niño events. Central Pacific coral data also show increased variability, although less distinctly than in the Galápagos. Our results provide long-term context for understanding ENSO variability trends, with troubling implications for climate extremes.
The vibrant biodiversity of the Galápagos Islands has helped biologists from Charles Darwin onward unlock the mysteries of evolution. Now, corals growing around the archipelago in the tropical Pacific Ocean are providing clues to another enduring puzzle: whether global warming is changing El Niño, the recurring Pacific climate cycle that drives extreme weather around the world.
Climate models have offered conflicting answers so far. Historical El Niño records are too short to reveal a clear trend. And El Niño’s own large natural swings have made it difficult to tease out any human influence.
But a 1000-year archive preserved in fossil corals from the Galápagos offers some of the strongest evidence yet that global warming is already making El Niño stronger. Reporting today online in Science, researchers found that temperature swings recorded in Galápagos corals—a place where the El Niño signal is strong—have intensified by 36% over the past 4 decades, far beyond anything seen in previous centuries. Along with other coral results elsewhere in the Pacific, the findings suggest “there’s something about this important source of climate extremes that has already changed in recent decades,” says Kim Cobb, a climate scientist at Brown University who was not part of the study.
Continue reading “Is Giant El Niño Evidence of a Climate Change Trend?”



