Photo: Dawid Adam Iurino/PaleoFactory/Sapienza University of Rome
Scientists at Stanford University have uncovered new details about the largest mass extinction in Earth's history, suggesting that extreme heat and oxygen loss in the oceans played a major role.
The Permian-Triassic extinction, which occurred around 252 million years ago, was triggered by massive volcanic eruptions that released huge amounts of greenhouse gases into the atmosphere. Global temperatures rose dramatically, while ocean oxygen levels declined.
Researchers compared the environmental tolerance of 38 species, including nine representatives of ancient Paleozoic marine fauna and 29 species from groups that dominate modern oceans. They found that Paleozoic species were generally more vulnerable to rising temperatures and declining oxygen levels.
According to the study, many of the organisms that dominated marine ecosystems before the extinction had slow metabolisms, making them particularly susceptible to rapid environmental changes. Modern groups such as mollusks, fish, sea stars and sea urchins proved more resilient.
The researchers also found that some ancient species could tolerate low oxygen levels while inactive, but this advantage disappeared when they became active.
Scientists stress that other factors, including ocean acidification, also contributed to the mass extinction.
The findings have implications for the modern climate crisis. During the Great Permian Extinction, global temperatures increased by an estimated 8–12°C over thousands of years. Today, scientists project warming of roughly 1.5–4°C above pre-industrial levels by 2100, depending on future emissions.
Stanford researchers warn that while the current situation is not identical to the Permian catastrophe, the parallels highlight the risks of rapid climate change. At the same time, they emphasize that reducing greenhouse gas emissions could still prevent the worst-case scenarios.
