Top 10 Worst Extinction Events in History

The Ordovician-Silurian Extinction, driven by rapid glaciation, caused sea levels to plummet by 80 meters, destroying shallow marine habitats and killing 85% of marine species. As the first of the 'Big Five' mass extinctions, it was 5% more effective than the Late Devonian Extinction in marine species loss, though 11% slower than the Permian-Triassic Extinction in total extinction rate. Its glacial trigger made it a unique 80-meter sea-level drop event.

The Triassic-Jurassic Extinction ranks among the 'Big Five' mass extinctions in Earth's history, wiping out roughly 70 to 75% of species. Massive volcanic eruptions from the Central Atlantic Magmatic Province pumped enormous volumes of CO2 and sulphur dioxide into the atmosphere in pulses over some 600,000 years, triggering catastrophic global warming and ocean acidification. The extinction eliminated many large terrestrial amphibians and reptiles, while life in the seas suffered heavy losses.

The Holocene Extinction is the only ongoing event on this list, with modern extinction rates running 100 to 1,000 times higher than the natural background rate. Since 1500, at least 875 species have been officially declared extinct, but the true figure is likely many times higher.

The Quaternary Megafauna Extinction claimed over 90 genera of large mammals worldwide, including woolly mammoths, sabre-toothed cats, and giant ground sloths, between 50,000 and 10,000 years ago. The primary driver remains debated: human hunting or climate change at the end of the last ice age.

The Capitanian Extinction, often overshadowed by the later Permian-Triassic mass die-off, devastated tropical marine communities with an estimated 35 to 47 percent species loss. Triggered by the Emeishan volcanic eruptions in present-day China—which covered over 250,000 square kilometers in lava—the event was slower than the average Permian crisis, but its impact on reef ecosystems was even more severe. This extinction is narrower in scope than (the Holocene Extinction) but still ranks as one of the most significant marine biodiversity collapses of the Paleozoic, preceding the planet's worst extinction by just 8 million years.

The Great Oxygenation Event is the single deadliest proportional extinction in Earth’s history, wiping out over 99% of anaerobic life—a kill rate 10x higher than the average extinction event. When cyanobacteria began mass-producing oxygen 2.4 billion years ago, they poisoned the dominant methane-producing archaea, triggering what scientists call the "Oxygen Catastrophe." This waste product reshaped the planet’s atmosphere, leaving only 0.1% of existing species able to survive. As a result, this event outkills #10 by eliminating nearly 100% of the anaerobic biosphere, making it far more devastating than the Eocene-Oligocene transition.

This mass die-off eliminated 50% of tropical marine mollusks and numerous terrestrial species, but simultaneously gave rise to modern fauna like horses, dogs, and grasses. The rapid turnover outpaced the Great Oxygenation Event’s environmental change by a factor of 4, making it the swiftest climatic upheaval since that catastrophic oxygen surge.