The Permian extinction

The ancient mass extinction of the Permian geological period happened 250 million years ago. 95% of the species went extinct! Scientists have found evidence that volcanoes spilled out large amounts of CO2 which led to global warming and heated up the Permian ocean. Warm water cannot retain much oxygen and Hydrogen sulphide then starts to produce from the bacteria thriving in such waters. Hydrogen sulphide permeated the late Permian ocean and bubbled out of the oceans and killed life in the oceans and then on land too.