Ancient coral records reveal an unusual shift in Pacific climate behavior. The consequences could reach far beyond the ocean, affecting weather and ecosystems worldwide.
The El Niño phenomenon in the tropical Pacific is becoming noticeably stronger amid global warming. This is the conclusion reached by the authors of a study published in the journal “Science.”
As mentioned by CNN
Scientists found that over the past 40 years, El Niño intensity has been, on average, 36% higher than during the preindustrial period. Compared with events in the 20th century, modern manifestations of this climate phenomenon have intensified by approximately 16%.
For the study, the team analyzed modern and fossil corals from the Galápagos Islands. This region lies in the eastern tropical Pacific, where El Niño forms and gains strength. Chemical traces in coral skeletons made it possible to reconstruct seawater temperatures over past centuries.
Corals preserve in the chemical composition of their skeletons a history of the conditions in which they grew, and we can recover that history by measuring this composition.
– Julia Cole
Why stronger El Niño is linked to global warming
Researchers compared a coral record spanning thousands of years with projections from 12 modern climate models. This approach helped distinguish natural climate variability from the unusual changes observed in recent decades.
The study’s authors do not claim that human influence on the climate has already been conclusively proven as the direct cause of stronger El Niño events. However, the findings indicate that the most likely explanation for the current trend is global warming caused by human activity.
Something extraordinarily unusual is happening now, and it is likely linked to human-caused climate change.
– Jonathan Overpeck, dean of the University of Michigan’s School for Environment and Sustainability
How El Niño affects weather around the world
El Niño occurs when sea surface temperatures in the equatorial Pacific rise above normal and atmospheric circulation changes. The phenomenon can affect average global temperatures and cause major weather anomalies in different regions of the planet.
Strong El Niño phases are associated with higher risks of droughts, floods, heat waves, and other extreme weather events. They can harm communities, agriculture, and natural ecosystems.
The study also showed that the amplitude of transitions between the warm El Niño phase and the cooler La Niña phase is increasing. The main driver is the strengthening of the cycle’s warm phases, which could make climate risks even more severe.
Ocean warming threatens coral reefs
At the same time, warming seawater poses a danger to the very corals that enabled scientists to study ancient climate history. Excessively warm water causes coral bleaching, while prolonged temperatures above their limits can lead to coral death.
Thus, stronger El Niño is not only a sign of changes in the global climate system, but also an additional threat to marine ecosystems that help humanity better understand the consequences of planetary warming.