Temperature-dependent hypoxia explains biogeography and severity of end-Permian marine mass extinction

Rapid climate change at the end of the Permian Period (~252 million years ago) is the hypothesized trigger for the largest mass extinction in Earth’s history. We present model simulations of the Permian/Triassic climate transition that reproduce the ocean warming and oxygen (O₂) loss indicated by the geologic record. The effect of these changes on animal survival is evaluated using the Metabolic Index (F), a measure of scope for aerobic activity governed by organismal traits sampled in diverse modern species. Modeled loss of aerobic habitat predicts lower extinction intensity in the tropics, a pattern confirmed with a spatially explicit analysis of the marine fossil record. The combined physiological stresses of ocean warming and O₂ loss can account for more than half the magnitude of the “Great Dying.”