Scientists Think a Mega-El Niño Helped Spark the ‘Great Dying’
While El Niño climate patterns today are responsible for prolonged droughts and high temperatures, during the end-Permian (some 251 million years ago), they contributed to what was nearly the end of all life on Earth.
A new study shows how mega El Niños—sometimes lasting as long as a decade—created prolonged periods of droughts and floods, making it impossible for animals to adapt to changing climactic conditions.
These mega El Niños help explain why the end-Permian mass extinction—largely driven by carbon dioxide pouring out of the Siberian Traps—was so particularly deadly compared to other mass extinction events.
Life—in its myriad forms and billions of years on Earth—hasn’t ever experienced as harrowing an event as the end-Permian mass extinction. Fittingly known as The Great Dying, this period saw the disappearance of an estimated 90 percent of all species on the planet, and caused marine and terrestrial collapse around the world. The driving force behind the disaster: an intense global warming attributed to a massive outpouring of carbon dioxide from the Siberian Traps.
And while this massive volcanic event (the largest in Earth history) was likely the engine behind this extinction, scientists weren’t exactly sure what natural mechanism flipped the ignition switch. Meanwhile, other mysteries remained, such as why usually hearty forms of life (like trees and insects) were affected by the extinction, and why animals didn’t simply migrate to cooler climates.
Now, a new study from the University of Bristol and China University of Geosciences (Wuhan) claims that global warming caused conditions to swing wildly over decade-long intervals, resulting in “mega El Niños” lasting much longer than today’s predictable climate patterns. The results of this study were published last week in the journal Science.
“Climate warming alone cannot drive such devastating extinctions because, as we are seeing today, when the tropics become too hot, species migrate to the cooler, higher latitudes,” Alexander Farnsworth—a co-author of the study from the University of Bristol—said in a press statement. “Our research has revealed that increased greenhouse gasses don’t just make the majority of the planet warmer, they also increase weather and climate variability making it even more ‘wild’ and difficult for life to survive.”
Today, El Niños typically last a year or two, and can bring big changes in rainfall and temperature patterns. In 2024, for example, an El Niño-fueled widespread heatwaves in June and contributed (along with anthropogenic carbon emissions) to the year 2023-2024 being one of the hottest on record. However, around 251 million years ago, these climate patterns instead spanned at least a decade each. The extended phenomena caused prolonged droughts followed by prolonged floods, which would have made it incredibly difficult for species to adapt to changing conditions.
The researchers found evidence of this “wild” climate variability by studying the oxygen isotopes in the fossilized teeth of conodonts—an extinct group of eel-like, jawless vertebrates who were one of the few animals to survive the end-Permian extinction. What they found was a complete collapse of temperature gradients in mid and lower latitudes.
“Essentially, it got too hot everywhere. The changes responsible for the climate patterns identified were profound because there were much more intense and prolonged El Niño events than witnessed today,” Farnsworth said in a press statement. “Species were simply not equipped to adapt or evolve quickly enough.”
Additionally, charcoal found in the rock layers associated with this period also confirms that the world was plagued by immense wildfires caused by prolonged drought. The researchers describe the Earth at this time as “stuck in a crisis state,” with the continents burning and the oceans stagnating. Although nowhere on Earth was safe, land-based animals had it the worst, and nearly no terrestrial animals were able to adapt to the planet’s wild climate.
“Only species that could migrate quickly could survive, and there weren’t many plants or animals that could do that,” Yadong Sun—lead author of the study from China University of Geosciences, Wuhan—said in a press statement. “But thankfully a few things survived, without which we wouldn’t be here today. It was nearly, but not quite, the end of the life on Earth.”
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