End-Permian Mass Extinction: Patterns, Processes, and Lessons for the 21st Century

The end-Permian mass extinction, which occurred approximately 252 million years ago, was the most severe biodiversity crisis in the history of animal life. In the marine fossil record, about half of known animal families and 80% of genera were lost. Heavily calcified taxa with limited development of respiratory and circulatory systems are disproportionately represented among the victims. The geological record of the extinction interval contains chemical evidence, some based on newly developed proxies, of rapid global warming, ocean acidification, and ocean deoxygenation. High-precision age dating shows that eruption of the Siberian Traps large igneous province occurred during the extinction interval, providing a plausible mechanism for rapid and extreme environmental change. Earth system models can now replicate the environmental changes indicated by chemical proxies and the habitat space available to marine animals can be represented in these models based on a ratio of oxygen supply to metabolic demand. The model representation of biological response to global change predicts the observed gradient in extinction intensity from equator to pole, suggesting that temperature-induced hypoxia was a major direct cause of population collapse. Parallels between end-Permian and Anthropocene environmental changes can enable calibration of models designed to predict responses of the marine biosphere to environmental change anticipated over the next few centuries.