More than 252 million years ago, 90 percent of marine and terrestrial species, from snails and small crustaceans to early forms of lizards and amphibians, abruptly died out. The end-Permian extinction, also known as the “Great Dying,” was the most severe mass extinction in Earth’s history and probably the closest life has come to being extinguished. Possible causes include immense volcanic eruptions, rapid depletion of oxygen in the oceans, and—though this is unlikely—an asteroid collision.

Although the causes of this global catastrophe are unknown, an MIT-led team of researchers including EAPS professor Sam Bowring has now established that the end-Permian extinction was rapid: mass die-outs both in the oceans and on land took less than 200,000 years—the blink of an eye in geologic time. The researchers also found that this time period coincides with a huge buildup of atmospheric carbon dioxide that probably triggered the collapse.

With further calculations, the group found that the average rate at which carbon dioxide entered the atmosphere during the end-Permian extinction was slightly below today’s rate of carbon dioxide release due to fossil-fuel emissions alone. It is thought that in less than 20,000 years during this period, increases in atmospheric carbon dioxide triggered severe global warming, accelerating species extinction. It probably took five million years for Earth’s ecosystems to recover from the devastation.