According to these scientists' estimates, this mass extinction is the fastest in Earth's 4.5-billion-year history. Unlike prior extinctions, this so-called "sixth extinction" is mainly the result of human activity and not natural phenomena.
Among the findings revealed by the survey, scientists identified the maintenance of biodiversity — the variety of plant and animal species and their habitats — as critical to human well-being; they rate biodiversity loss as a more serious environmental problem than the depletion of the ozone layer, global warming, or pollution and contamination. The majority (70%) polled think that during the next thirty years as many as one-fifth of all species alive today will become extinct, and one third think that as many as half of all species on the Earth will die out in that time.
—American Museum of Natural History press release, 20 April 1998
And, in case you're wondering about the other five extinctions, they are as follows: the Ordovician-Silurian event (about 439 million years ago; extinction of 25% of marine families and 60% of marine genera); Late Devonian event (about 364 mya; extinction of 22% of marine families and 57% of marine genera); Permian-Triassic event (about 251 mya; extinction of 95% of all species, 53% of marine families, 84% of marine genera and an estimated 70% of terrestrial species); terminal Triassic event (199-214 mya; extinction of 22% of marine families, 52% of marine genera, impact on terrestrial organisms unclear); Cretaceous-Tertiary event (65 mya; 16% of marine families, 47% of marine genera; and 18% of land vertebrate families — this is the one that got the dinosaurs). Of course, as the AMNH press release pointed out, there's one way that the present event is very different from these earlier extinction events. They were brought about by asteroid impacts, the rising and lowering of sea levels, the drifting of continents, mass vulcanism, and so forth. Never before in the 3.5-billion-year history of our biosphere has a single species triggered a major extinction event.
On our present course, this may eventually stand as the ultimate achievement of Homo sapiens sapiens. We should take a bow. We are obviously planet killers. The question is, can we also be planet saviors? I'd say that seems unlikely.
Happy Earth Day.
Meanwhile, I spent most of yesterday preparing to write my next short story (and trying not to be anxious about the proposal for my next novel). Mostly, I spent the time reading articles on transhumanism, posthumanism, body modification, bioengineering, cloning, and so forth. I'll probably spend much of the weekend reading. I'd wanted to begin writing the story today, but I have to leave for Birmingham, either tonight or tomorrow, for the Alabama Bound book fair beginning Friday night, and I'd hate to get something started and then have to stop working on it for a couple of days. Better, instead, to begin on Sunday. It'll give me more time to research and ponder, anyway.
Last night we played War of the Monsters and I finally kicked Spooky's ass.