The Great Dying clears the stage
Earth's largest extinction ends the Permian and opens the age of dinosaurs
Quick facts
- When
- About 252 million years ago
- Scale
- More than 95% of all species eradicated
- Rank
- The largest mass extinction in Earth's history
- Suspected cause
- Massive Siberian volcanism (not fully settled)
What happened
The Mesozoic Era, the age of dinosaurs, began in the aftermath of catastrophe. About 252 million years ago the Permian-Triassic extinction, which the Natural History Museum calls the Great Dying, wiped out more than 95 percent of all species and stands as the largest mass extinction in Earth's history. On land and in the seas, most life was eradicated. The exact trigger is still argued over, with huge volcanic eruptions in what is now Siberia among the leading suspects, and by some estimates the planet took millions of years to recover.
Why it matters
This is the doorway into the whole age of dinosaurs. The Great Dying emptied the world of most of its animals, and the survivors radiated into the empty space over the following period, one lineage of which became the dinosaurs. Without this near-total reset, the reptiles that came to dominate the Mesozoic might never have had the opening.
How we know
The Natural History Museum describes the Permian-Triassic extinction as the Great Dying, dates it to the boundary about 252 million years ago at the start of the Triassic, states that more than 95 percent of species were eradicated, and notes that the precise cause is not fully understood.
Sources
- Natural History Museum, London. What is mass extinction, and are we facing a sixth one? (Natural History Museum) (2024) · Reputable sourcenhm.ac.uk · The domain "nhm.ac.uk" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- Natural History Museum, London. The Triassic Period: the rise of the dinosaurs (Natural History Museum) (2024) · Reputable sourcenhm.ac.uk · The domain "nhm.ac.uk" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- Burgess, Bowring & Shen. High-precision timeline for Earth's most severe extinction (PNAS, 2014, via PubMed Central) (2014) · Peer-reviewed (author-declared)pmc.ncbi.nlm.nih.gov · Cited as a "journal" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
See something wrong? . Corrections with a source get fixed fastest.
Part of a timelineAge of Dinosaurs21 events · The age of the dinosaurs across the Mesozoic Era, from the Great Dying that cleared the way to the asteroid that ended their reign.View all →