The Great Dying: Earth’s Most Severe Extinction Event

Approximately 252 million years ago, Earth experienced its most catastrophic loss of life in history – a mass extinction event known as the “Great Dying.” This devastating period wiped out an estimated 90% of all species, fundamentally reshaping life on our planet.

What Was the Permian-Triassic Extinction Event?

The Permian-Triassic extinction event, occurring at the boundary between the Permian and Triassic geological periods, marks the end of the Paleozoic Era and the beginning of the Mesozoic Era.¹ It is considered the most severe known extinction event in Earth’s history.¹

The Scale of the Extinction

The scale of the Great Dying is staggering. Estimates suggest the extinction of:

• 57% of biological families
• 62% of genera
• 81% of marine species¹
• 70% of terrestrial vertebrate species¹
• The greatest known mass extinction of insects¹

This event surpasses even the extinction of the dinosaurs in terms of the sheer number of species lost.³

What Caused the Great Dying?

The primary driver of the Permian-Triassic extinction is believed to be massive volcanic activity in the Siberian Traps, a vast volcanic rock region in north-central Russia.² This volcanic activity released enormous quantities of carbon dioxide and sulfur dioxide into the atmosphere, leading to:

• Intense global warming²
• Ocean acidification
• Widespread oceanic anoxia (reduced oxygen levels)²

These environmental shifts caused ecosystems to collapse and food chains to be disrupted, leading to widespread extinctions.

The Prolonged “Super Greenhouse” Effect

Scientists have long puzzled over why the Earth remained exceptionally hot for approximately 5 million years after the initial volcanic activity ceased. Recent research suggests the collapse of tropical rainforests played a crucial role.³ The loss of these forests reduced the planet’s capacity to absorb carbon dioxide, exacerbating the greenhouse effect and prolonging the period of extreme heat.

Recovery and the Rise of New Life

The recovery of life following the Great Dying was a lengthy process, taking approximately 10 million years.² During this time, ecosystems were gradually re-established and diversified, paving the way for the emergence of new life forms, including early ancestors of dinosaurs and various marine species like crabs and lobsters.²

Lessons for Today

The Permian-Triassic extinction event serves as a stark reminder of the profound impact that large-scale environmental changes can have on life on Earth. Understanding the causes and consequences of this event is crucial as we face our own period of rapid climate change and biodiversity loss.³