For many years, scientists have believed Earth is in the midst of the Sixth Mass Extinction. The disappearance of populations within a species, an event called extirpation, is occurring several orders of magnitude more frequently than species extinctions. Extirpation is a prelude to extinctions, which indicates that Earth’s ongoing Mass Extinction Event is proceeding faster than most people assume. Indeed, the conservative peer-reviewed literature indicated we were well into this event in 2017. The Mass Extinction Event was not far in the future in 2017. It was not beginning in the 2017. Earth was already well into this Mass Extinction Event in 2017.
However, the ongoing Mass Extinction Event is not the Sixth. Earth is in the midst of at least the Seventh Mass Extinction.
A peer-reviewed paper by Michael R. Rampino and Shu-Zhong Shen, published 5 September 2019 in Historical Biology: An International Journal of Paleobiology, indicates a Mass Extinction Event occurred about 259.8 million years ago. The paper identifies “the end-Ordovician (443.8 Ma), the Late Devonian (372.2 Ma), end-Permian (251.9 Ma), end-Triassic (201.4 Ma) and end-Cretaceous (66 Ma) events.” It reports the discovery of the “end-Guadalupian (end-Capitanian) (259.8 Ma)” Mass Extinction Event, squeezed between the Second and (previously) Third Mass Extinction Events. The authors conclude that “there were apparently six major Phanerozoic mass extinctions, and the current loss of species should perhaps be called the ‘seventh extinction.’”
Scientific discovery adds reliable knowledge. In this case, scientific discovery added a previously unknown Mass Extinction Event. There could be more. We know relatively little about the planet we call home.
Because the phrase has become reasonably well known, I will sometimes refer to the ongoing Mass Extinction Event as the Sixth. I appreciate your patience. At this point, calling the event the “Seventh Mass Extinction,” or more accurately, “At Least the Seventh Mass Extinction,” will only engender more confusion from the already confused populace.