Our Very Own Mass Extinction

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.

12 thoughts on “Our Very Own Mass Extinction

  1. Yup, humans are going to suffer horribly and maybe go extinct by their own hand.

    But it won’t be tomorrow so who cares!!

  2. Well, at least we’ll provide the first evidence of not-so-intelligent intelligent beings mucking everything up, for the next incarnation of intelligent beings to refer to.

    Well, except for the seaside residents…they’ll be the first to go I guess,
    Melting of Arctic ice sheet and 3 meters sea level rise inevitable – study

    • There’s also the grim possibility that there might never be a “next incarnation” of intelligent life on this planet, if we humans manage to wipe ourselves out. It took 4.5 billion years for the first one to emerge, after all. Post-human life will have a head start, especially if some apes and monkeys are still around, but I wouldn’t call the re-evolution of intelligence a foregone conclusion.

      As for sea level changes, an important consideration is how fast they happen. One of the papers mentioned in that Russia Today article says that sea levels will rise by less than 0.25 mm per year for the rest of this century. Even if that’s just the contribution of this collapsing Antarctic ice sheet, rather than the total predicted sea level rise (I can’t tell, from the abstract, which claim is being made), it’s still not much to worry about.

      • This article is slightly better

        The .25mm per year is just for the Thwaites Glacier, which acts as more of an “ice dam for the massive West Antarctic Ice Sheet” which would add another “3 to 4 meters” to sea level.

        All in all, they say somewhere between 200-1000 years timescale with 200-500 their bet. They said the faster timescale was too “chaotic” for them to model, and so they didn’t model it I guess.

        The way things have been going, I’d go with the shorter timescale at this point too.

        • Yes, that article is much clearer – thanks for digging it up. If we’ve got at least a couple of centuries before the West Antarctic Ice Sheet is likely to start making a large contribution to rising sea levels, then we’ve got time to figure out how best to deal with the problem. On the other hand, we’ll need to think about it before the last minute, something that doesn’t seem to be a particular talent of Canadian governments.

      • “Between 1870 and 2004, global average sea levels rose a total of 195 mm (7.7 in), and 1.46 mm (0.057 in) per year.[5] From 1950 to 2009, measurements show an average annual rise in sea level of 1.7 ± 0.3 mm per year, with satellite data showing a rise of 3.3 ± 0.4 mm per year from 1993 to 2009,[6] a faster rate of increase than previously estimated.[7] It is unclear whether the increased rate reflects an increase in the underlying long-term trend.[8]”

        From Wikipedia.

        • It is unclear whether the increased rate reflects an increase in the underlying long-term trend.

          I think we can safely say that it will always, forever and ever, be unclear whether a (non-annihilating) change today, reflects a change in the underlying long-term trend.

  3. People sometimes don’t understand that extinction events were drawn out so we are most likely living though one that probably rivals that of the great Permian extinction.

    • I hope you’re wrong about that – the Permian extinction wiped out more than 90% of marine species, supposedly, and I like to think that we might avoid doing quite that much damage. I agree, though, that the difference between human time scales and geological ones makes the current extinction seem a lot less drastic than it’s going to look to little green palaeontologists a few dozen million years from now.

      • This is one of the few things I would like to be wrong about but I don’t know – it seems pretty dire. Permian dire (oh, I think I’ve just made a new category of dire).

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