Nothing has so dramatically reconfigured the history of life on Earth as the epic mass extinction events that punctuate the fossil record stretching back at least half a billion years. One such episode, known as the end-Devonian mass extinction (or Hangenberg Crisis), occurred 359 million years ago, and as many as 75 per cent of species disappeared during this tumultuous period. During Earth’s last mass extinction event some 55 million years ago, known as the Paleocene-Eocene Thermal Maximum, rates of warming were 100 times slower than today’s human-induced climate shift, he notes. Ozone depletionNow, it seems the spectre of dangerous global ozone depletion may have returned. It is known that stratospheric ozone was also virtually obliterated during the end-Permian mass extinction event (or the Great Dying, as it is known) some 252 million years ago.

Source: The Irish Times January 28, 2021 04:52 UTC