Earth's Most Violent Catastrophe Wasn't an Asteroid

There were no polar ice caps. Forests reached into high latitudes, reefs crowded the warm shallow seas, and the climate had been stable for millions of years. Nothing in that world suggested what was coming. Then the crust split open along thousands of fissures, and up to 90 to 96 percent of all marine species were wiped out, along with roughly 70 percent of land vertebrates. This is the most violent event in the planet's history, and it did not arrive in a single afternoon. Flood basalts poured out for longer than our species has existed. Sulfur aerosols dimmed the sun and chilled the surface; when they washed out, the carbon dioxide left behind drove temperatures hard the other way. The oceans warmed, lost their oxygen and turned acidic, and bacteria in the stagnant depths filled the water with hydrogen sulfide. Then came the long night. Phytoplankton collapsed and took the marine food web down with them. Reefs disappeared. Forests burned and their soils washed into the sea. Trilobites, which had survived everything for hundreds of millions of years, were gone for good, and ferns and mosses inherited the emptied ground. All of it is still readable in the rock: carbon isotope excursions in limestone, black shales laid down in oxygen-free water, mercury spikes from volcanic ash, spore layers where forests failed, and ancient temperatures locked inside fossil shells. So what does it take to nearly sterilise a living planet? And how do you read a catastrophe out of a layer of stone? Settle in for the full story, and subscribe for more feature-length documentaries on Earth's deep past. #MassExtinction #PrehistoricEarth #Documentary