There have been five truly enormous mass extinctions in Earth’s geological history, events in which (as the BBC puts it) “abnormally large numbers of species die out simultaneously or within a limited time frame”. The one that wiped out the (non-avian) dinosaurs and many other creatures at the end of the Cretaceous Period tends to soak up much of the public interest in the subject, but the extinction at the end of the Permian seems to have been more devastating in terms of the proportion of species that went on a sudden date with the Grim Reaper. The Ordovician and Triassic Periods also ended with mass extinctions, and there was another in the Late Devonian. If a unique, omnipotent deity has been overseeing Earth’s progress towards its present state, she’s clearly in the habit of frequently reaching for her eraser, rubbing out the vast majority of her creations, and then using the few survivors as a basis for subsequent fits of innovation. Just the artistic temperament, I suppose.
The idea that we are now in the midst of a sixth mass extinction is now commonplace, and probably correct. Humans have arguably been wiping out species through overhunting for tens of thousands of years. In the past few hundred, we’ve been causing enormous devastation not only through old-fashioned hunting but also through habitat destruction, introduction of invasive species to various parts of the world, and even anthropogenic global warming. Species are dropping like flies, especially when the rate of extinction is considered on a geological time scale, and some of the survivors continue to exist only because of Herculean efforts to protect them.
I think our planet’s recent biological losses are deplorable, and I hope it will be possible to stem the tide of destruction. I would hate to see the black rhino or the kakapo go the way of the dodo, the moa and the passenger pigeon. Apart from wanting to ensure that future generations of humans have the opportunity to observe these animals, and indeed to stalk and kill them at sustainable rates if that’s how they prefer to spend their vacations, I can’t quite shake the arguably irrational feeling that biodiversity makes the world more beautiful and interesting in some deep sense that even alien spacefarers would be likely to appreciate. The great Canadian writer, naturalist and soldier Farley Mowat, who died just a few days ago at the ripe old age of 92, might well have agreed.
However, there’s another side to the story, or at least another way to look at it. Previous extinctions have been caused by major perturbations like asteroid impacts and periods of heightened volcanic activity, and the current biotic crisis is the only one that seems at all likely to have been precipitated by the environmental impact of a single species. We humans have had astonishingly wide-ranging effects on the rest of the biosphere, as hunters, farmers and industrialists. We haven’t needed any divine imprimatur to achieve, in an imperfect but very real sense, “dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth” (Genesis 1:28). Unfortunately, power doesn’t necessarily come with wisdom and restraint, and we seem to be wielding ours in ways that are wondrous but also destructive. Perhaps the name of our species should be changed from Homo sapiens, “wise man”, to Dinopithecus dynatus – which, if I’m getting the Latinized Greek right, should mean something like “mighty, terrible ape”. We’re one hell of a primate, the closest thing to a race of gods that the Earth has ever produced, but there are good reasons to relegate gods to a safely distant place like Olympus or Asgard. When they’re allowed to run riot here on delicate Midgard, their powers and caprices are too dangerous.