New Evidence Reveals There was a Sixth Mass Extinction in Earth's History

Since the Cambrian Explosion, ecosystems have suffered repeated mass extinctions: five in total. Now, scientists have identified a sixth major extinction that occurred 262 million years ago in China.

The "Big 5" crises are the most prominent mass extinctions in our history. The sixth one, though, has long been controversial. About twenty years ago, scientists recognized this extinction as occurring in the Middle Permian of China, when paleontologists teased apart losses from the "Great Dying" at the end of the period. While the extinction was recognized, though, researchers were unsure whether or not it was a global event.

Until now, this Captanian extinction was known only from equatorial settings. In other words, it seemed to be localized rather than global. Now, though, researchers may have found evidence to suggest otherwise and to name it as one of the mass extinctions that impacted our planet.

The scientists discovered evidence for severe Middle Permian losses among brachiopods in northern paleolatitudes. More specifically, they found that the Boreal crisis coincided with an intensificatiiion of marine oxygen depletion, implicating this killer in the extinction scenario.

The widespread loss of carbonates across the Boreal Realm also suggests a role for acidification. The new data cements the Middle Permian crisis's status as a true "mass extinction." Thus, the "Big 5" extinctions should now be considered the "Big 6."

The findings are published in the journal Geological Society of America Bulletin.

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