Climate modeling links volcanoes and mass extinctions

Ars Technica : To study the effects of large volcanic eruptions on Earth’s life forms, researchers led by Benjamin Black of MIT used a global climate model based on a historically catastrophic event—the Siberian Traps eruptions that occurred during the Permian period almost 300 million years ago. That event resulted in the most devastating mass extinction on record. To understand why, the researchers looked at the atmospheric chemistry that evolves during such an eruption. Emission of carbon dioxide and sulfur dioxide into the atmosphere can cause acid rain, and the heat from magma can metamorphose surrounding rock and cause chloride-containing gas and methane to be released, which depletes Earth’s ozone layer. The group found that the combination of the two—strongly acidic rain and global ozone collapse—in conjunction with atmospheric warming from greenhouse gas emissions, ultimately proved fatal for many of Earth’s land-dwelling organisms.