Whimper wants a bang

The interpretation of Earth’s evolutionary history as a five-act play, with a farce tacked on the end as envoi, certainly appeals to my dramatic sense. As gentle reader may know, each grand period or biotic Act ends with a massive extinction event. We have the curtains close on the Ordovician, the Devonian, the Permian, and the Triassic, repectively; then finally on the Cretaceous, with a big dinosaur kill-off, just 66 million years ago — each of these events leaving more bodies on stage than a Jacobean revenge tragedy. The causes were “whatever,” as we say today. Asteroid, maybe; gargantuan volcano; little green men zapping noxious pink rays.

Look at the chart (it’s scattered around the Wicked Paedia) and the drama becomes less clear. It is constructed from current fossil knowledge, at the level of genera. It is founded on a statistical count of when the last species in each known genera disappears, permanently, off stage. We haven’t actually seen him die, but in each case, we never see him again. (Except, sometimes we do find him, swimming unselfconsciously in the Indian Ocean as if nothing had happened, in which case we must remember to adjust our extinction count, and make a poster for another “endangered species.”)

The presumed extinctions tend to bunch here and there, as waves may do at sea. For the play subdivides into scenes as well as acts, and lines within each scene. And even on the great acts, those curtains tend to close in “pulses” — as if the pulleys are jammed, and the stage manager must yank the cords again and again, and they never quite shut completely.

From the pop-science press I gather that “settled science” has moved in on the cause of the Permian/Triassic “boundary event” — the biggest of the big kill-offs. That is just where Shakespeare likes to put his climax: about the end of Act Three. This leaves him two more acts to sort out the mess he has created. In this case, the mess is now attributed to the Siberian Traps.

The Earth scientists now believe this vast region of igneous rock in present-day north-west Siberia (formerly northern Pangea) began tooting the greenhouse gases, big time, around 252 million years ago, and kept it up for over one million years. In addition they spewed more than one million cubic miles of lava — enough to cover the whole planet, more than thirty feet deep.

“Yikes,” will be our first reaction. Pump me full of greenhouse gases, and bury me under three storeys of molten lava, and I would consider going extinct, myself. And I’d be looking suspiciously at anyone who wasn’t. It sounds like a planetary Pompeii.

But note: “over a million years.” That’s less than one three-thousands of an inch per year; about what I expect falls on the cleanest city in the form of dust. Much less, in fact, because the rocks of the Siberian Trap are mostly basalts formed from lava that doesn’t much shoot upward; it just spreads and blobs on location. And note, another little fact I’ve not yet supplied: that the extinctions peak just after all this heaving. Then further note, that all of this depends on dating methods that can of themselves be plus-or-minus a couple million years; and cannot be checked against the actual sequence of events, until time agrees to move backward. (Only in my dreams.)

I can’t help it, gentle reader, I am one of nature’s sceptics. Show me a “theory” and I start feeling for holes. Often enough I find that it is a conjuring trick, some prestidigitation; a little hocus-pocus performed on the gullible, and information-starved. (“Modern science is like magic.”) The audience imagines thirty feet of lava falling all at once. The reality is a few specks of soot.

One might also note that the greatest devastation occurred not on land, but underwater. (The fact that sea levels appear to have been plunging at the time, makes a curious aside.)

I, like any clever scienticist, could fuddle with the data till my eyes crossed, then shrug and postulate various “events within the event” — weaves, turns, sprints, wrinkles, leaps, bobbles — plus an unknown number of additional “whatevers.” But I wouldn’t go on television until I’d found hard evidence of my purely speculative play-by-play. Smoking guns are all very well, but a coroner requires a one-to-one pairing between bullets and wounds.

As the wide-eyed propagators of the BBC put it: “The precise details of how this caused so many life forms to die out remain the subject of scientific discussion.”

Or as I would paraphrase: “They don’t have a chuckling clew.”

This leaves us with my promised farce, or “Act Six” in the programme. This is the one we are watching now. In this one we have, at present, more than seven billion “fully-evolved” humans looking for the next extinction event. Vain little creatures who, tired of waiting, think they can cause it themselves.