The largest extinction event in Earth’s history, which occurred 252 million years ago during the Permian-Triassic warming, has been linked to mega ocean warming El Niño events, according to new research published in Science. Scientists have previously connected this mass extinction to massive volcanic eruptions in Siberia that released large amounts of carbon dioxide, leading to rapid climate warming. However, the extent of the devastation on both land and in the sea has remained a mystery until now. The study reveals that increased greenhouse gases not only make the planet warmer but also increase weather and climate variability, making it difficult for life to survive.
The research, led by the University of Bristol and China University of Geosciences (Wuhan), shows that the Permian-Triassic catastrophe was not just a matter of becoming unbearably hot but also involved wild swings in climate conditions over decades. The study of oxygen isotopes in fossilized tooth material of extinct swimming organisms called conodonts revealed a collapse of temperature gradients in low and mid latitudes. Climate modeling conducted by Dr. Farnsworth demonstrated that the intense and prolonged El Niño events during this period made it too hot for many species to adapt or evolve quickly enough, resulting in widespread extinctions.
The study also sheds light on the impact of El Niño events on recent climate patterns, such as the extreme weather conditions that led to the North American heatwave in June 2024 and one of the hottest years on record in 2023-2024. The researchers note that while recent El Niño events have lasted one to two years, during the Permian-Triassic crisis, El Niño persisted for a decade, resulting in widespread drought followed by flooding. This erratic climate made it extremely challenging for species to adapt and survive, leading to a crisis state where wildfires were common on land, and the oceans were stagnating.
The abundance of charcoal found in rock layers from the Permian-Triassic age can be attributed to the frequent wildfires caused by the drought-prone climate during this period. The researchers observed that while volcanic events similar to those in Siberia have caused extinctions throughout Earth’s history, none have led to a crisis of the scale seen during the Permian-Triassic event. Mega-El Niños during this time created positive feedback on the climate, leading to incredibly warm conditions that caused vegetation dieback, disrupting the Earth’s mechanisms for removing CO2 from the atmosphere.
The study also addresses the conundrum of the Permian-Triassic mass extinction, where land extinctions occurred tens of thousands of years before extinctions in the oceans. The researchers explain that while the oceans were initially shielded from temperature rises, the mega-El Niños caused temperatures on land to exceed most species’ thermal tolerances at rapid rates, preventing many plants and animals from adapting in time. Mass extinctions, although devastating, are part of Earth’s natural system that allows for the reset of life and evolution along different paths. The researchers conclude that the Permo-Triassic mass extinction ultimately led to the rise of dinosaurs as the dominant species, demonstrating the significant impact of these events on Earth’s history and evolution.