Approximately 252 million years ago, extreme ocean warming caused by El Niño was the primary cause of the largest mass extinction event in Earth’s history. The Permian-Triassic warming event wiped out 80-90% of Earth’s species, sending out a stark warning as the planet continues to warm. The new view that ocean warming played a major role in this volatile period in Earth’s history suggests that The study was published in the journal Neurology on September 12th. Science.
The Great Extinction
of Permian-Triassic mass extinctionAlso known as the Great Dying, this event was caused by a massive volcanic eruption in what is now Siberia. The volcano spewed toxic gases into the atmosphere, and rising carbon dioxide emissions caused temperatures across the globe to rise sharply. The Great Dying paved the way for the dinosaurs to eventually dominate the Earth, but it was even worse than the Cretaceous-Paleogene extinction that wiped out most of the dinosaurs about 66 million years ago.
Increased carbon dioxide and ultraviolet radiation from volcanoes caused both marine and terrestrial ecosystems to collapse, but why land plants and notoriously hardy insects suffered as much as plants in the world’s oceans remains a scientific mystery.
[Related: This tiger-sized, saber-toothed, rhino-skinned predator thrived before the ‘Great Dying.’]
“Climate warming alone cannot cause such catastrophic extinctions because, as we see today, when the tropics get too hot, species migrate to cooler, higher latitudes,” says study co-author Alexander Farnsworth, a meteorologist and climatologist at the University of Bristol in the UK. It said in a statement“Our research shows that increasing greenhouse gases will not only warm much of the planet, but will also make weather and climate more variable and more ‘wild’, making it more difficult for life to survive.”
According to the teamThis disaster shows that global warming is not just a matter of the Earth becoming unbearably hot, but that it can also cause conditions to fluctuate wildly over decades.
“Most life could not adapt to these conditions, but thankfully some organisms survived, without which we would not be here today,” said study co-author Yadong Sun, a paleoclimatologist at the China University of Geosciences. It said in a statement“It was close to the end of life on Earth, but not quite the end.”
Temperature measuring teeth
So study, To get a complete picture of global warming from the Permian to the Triassic, the research team Oxygen Isotopes Among the fossilized teeth of extinct swimming creatures, ConodontsThese tiny marine invertebrates Less than 1 inch long It may be distantly related to modern hagfish.
The team used oxygen isotopes to understand the temperature changes experienced by conodont specimens around the world and constructed various climate models, which suggest that the temperature gradient decreased significantly at both low and mid-latitudes.
Animation of monthly average surface temperatures (Celsius) during the peak of the crisis caused by very high volcanic carbon dioxide emissions. Credit: Alex Farnsworth, University of Bristol
“Basically, it got too hot everywhere,” Farnsworth says. “The changes that caused the identified weather patterns were severe because El Niño events were much more intense and lasted longer than those we see today. Species simply weren’t ready to adapt or evolve quickly enough.”
Recently, the El Niño phenomenon has caused major changes in precipitation patterns and global temperatures. Record heatwave in June In some parts of the US, as late as 2023 The hottest year in world history One factor is a strong El Niño phenomenon in the Pacific Ocean, which is exacerbated by man-made increases in carbon dioxide in the atmosphere and is causing wildfires and droughts around the world.
[Related: The ‘living fossil’ that thrived during a mass extinction.]
“Fortunately, so far these events have only lasted for a year or two at a time,” said study co-author Paul Wignall, a paleontologist at the University of Leeds in the UK. It said in a statement“During the Permian-Triassic Crisis, El Niño events lasted much longer, which caused widespread decade-long droughts followed by years of flooding. Basically, the climate changed everywhere, which made it very difficult for any species to adapt.”
The climate model in this study also helps explain why so much charcoal was found in rock layers that are 250 million years old.
“Wildfires are so common in drought-prone climates that the Earth is in a state of crisis with land burning and oceans stagnating,” said study co-author David Bond, a paleontologist at the University of Hull in the UK. It said in a statement“There was nowhere to hide.”
Migrate to survive
of The team also observed There were many volcanic events like the one that occurred in Siberia millions of years ago, many of which led to extinction events, but none on the same scale as the Permian-Triassic event.
These giant El Niño events likely made the Permian-Triassic mass extinction so devastating. Positive feedback loop The climate changed, with extremely warm weather starting in the tropics and working outwards. This heat killed most of the Earth’s plant life. Plants are essential for removing carbon dioxide from the atmosphere and are the basis of the Earth’s food chain. When too many plants died, they were lost along with the Earth’s mechanism for preventing carbon dioxide from building up in the atmosphere through continued volcanic activity.
This feedback loop also helps explain how the Permian-Triassic mass extinction on land occurred tens of thousands of years before the marine extinction.
“At first, the oceans were not affected by the rising temperatures, but the mega El Niño event caused temperatures on land to rise so quickly that most species could not adapt in time,” Sun said. “Only those that could move quickly could survive, and not many plants and animals could do that.”
[Related: A boiling hot supercontinent could kill all mammals in 250 million years.]
Mass extinctions, although rare, have proven central to natural systems resetting life and also driving evolution.
“The Permian-Triassic extinction was devastating, but it ultimately led to the rise of the dinosaurs, who went on to become the dominant species,” Farnsworth said, “just as the Cretaceous extinction led to the rise of mammals and humans.”
