THE SIXTH EXTINCTION
Elizabeth Kolbert, who did all the hard work on THE SIXTH EXTINCTION, (writing is, indeed, hard work) creates a non-fiction account of the history of five previous mass extinctions recognized by science while laying the groundwork for labeling many currently endangered species headed for extinction.
Science recognizes five previous mass extinctions each occurring at the very end of one historical epoch or as a significant element at the start of a new epoch.
We are currently at the beginning of the Anthropocene Epoch with its own mass extinction going on. Mass extinctions are pretty much just that: PeriodS when there is a significant reduction in the number of species living on Earth.
That includes homo sapiens. As one commentator put it, "man is very busy sawing off the very limb he is perched on." It has generally been recognized that Man has caused ocean acidification, global warming, and vast changes to the ecosystem that resulted in habitat loss for many species pushing many of those species to the edge of their ability to survive.