The Great Dying Earth's Worst Catastrophe and the Unlikely Survivors

Imagine standing on a beach at the end of the world. Not a metaphorical end — the literal, biological end of nearly everything. The ocean in front of you is warm, thick, and wrong. The water has turned acidic enough to dissolve the shells of the creatures living in it. The sky above is hazy with sulfur dioxide and carbon dioxide pumped out by volcanic eruptions that have been going on for tens of thousands of years. The forests behind you are dying. The insects are gone. The rivers carry the remains of things that have no names because no human has ever seen them, and no human ever will. This is Earth, 252 million years ago, at the peak of the event scientists call the Permian-Triassic extinction — or, more evocatively, the Great Dying.

It is the closest life on this planet has ever come to total annihilation. Up to 96 percent of all marine species vanished. Roughly 70 percent of land vertebrate species were erased. The complex food webs that had taken hundreds of millions of years to assemble collapsed in what amounts, in geological terms, to an eyeblink. The diversity of life on Earth was essentially reset — not to zero, but close enough that the difference might not have mattered. And yet, here we are. Life survived. More than survived — it eventually flourished in ways that would give rise to dinosaurs, mammals, and ultimately us. Today's episode is the story of how that happened. It's a story about catastrophe and tenacity, about the strange logic of survival, and about how the worst day in the history of complex life planted the seeds for everything that came after.