Around 252 million years ago, the “Great Dying” took out 90% of the world’s species. About 66 million years ago, a meteor caused the extinction of three out of four species, including those known to us as dinosaurs. After 1.8 million years of existence, our own species is triggering yet another mass extinction event, according to a study in the journal Science by Stuart Pimm and Clinton Jenkins. According to Pimm, species are now going extinct at about ten times faster than scientists had thought. Prior to the arrival of homo sapiens (i.e., our species), the extinction rate was about 0.1 out of a million species per year; as of 2014, the rate had climbed to 100 to 1000 species per 1 million. Behind this evolutionarily abrupt bump is not only the complicity of our species, but also unforeseen consequences that could easily take homo sapiens out of the equation.
The full essay is at “Humanity Getting Ahead of Itself”
 Seth Borenstein, “World on Brink of Sixth Great Extinction, Species Disappearing Faster than Ever Before,” The Huffington Post, May 29, 2014.