On Saturday, in less than 60 minutes, two academics raced through 4 billion years of Earth’s history, with time left over for questions. It was an enlightening and sobering experience for the 20 or so people present (an audience that included MCFly readers old and new). It happened at Blackwell’s bookshop on Oxford Road [the link lists the other five (free!) events over the coming week] one of the venues for this year’s Manchester Science Festival.
The academics in question, Dr Jan Zalasiewicz and Dr Mark Williams, both at University of Leicester, are co-authors of a book called “The Goldilocks Planet: the four billion year story of Earth’s climate.“
They whipped through it all at a cracking pace. Mark Williams started, and an early analogy was compelling; a hundred years ago the state of geological knowledge was like that of a 13th century person using the “mappa mundi”. Now, in 2012, we’ve upped our game to … the 16th century.
There was lots of interesting stuff about the early oxygen releases binding to iron (and laid down, now dug up and used for, well, anything you use iron for). Once the iron was exhausted, the oxygen levels went up (2.5 billion years ago), and you start getting “glacial deposits” (ice, to you and me.)
Apparently there were long periods (a billion years or so?!) where not much was changing – it’s actually called the boring billion!. However, it wasn’t that boring – eukaryotic life kicked in.
There are then a series of “snowball earth” events (readers of James Lovelock’s Gaia got to nod wisely at this point), and that was only broken by lots of big volcanoes, caused by plate tectonics (the continents shimmying and rubbing up against each other).
One of Mr Wiliams points was that life is extremely hard to exterminate once it gets going. He spoke of the “Dry Valleys” in the Antarctic, which are so inhospitable that NASA use them as a proxy for Mars. And yes, there’s life there.
Zalasiewicz and Williams have an interesting concept of “the Calcite Metronome” – a “tick tock” that takes 100s of millions of years, involving plate tectonics and the opening and closing of continents.
Dr Williams got as far as the carboniferous, and then handed over to his colleague, who brought us from then (445 million years ago) to now.
He whizzed through the last big cold snap – 37.5 million years ago, btw – the Pliocene epoch and into the ”modern” world.
This includes the Holocene – the unusually stable last 12,000 years (think of lots of squiggles followed by a plateau. But don’t think of the ECG of someone flat-lining!)
And into the Anthropocene, the last 200 years (well, it’s complicated actually – see the video I made last year. Embedded below.). Our burning of fossil fuels has raised C02 levels to where they were 3 million years ago…
Dr Zalasiewicz closed with the classic understatement “we might expect interesting climatic times ahead,” and in the q and a he quoted Wally Broecker – “unpleasant surprises in the greenhouse.”
The question, of course, is how to communicate that… And then what to do about it.
Things that stood out:
Life is older than I knew. 3.8 billion years, anyone?
There were periods where everything in the oceans died because there was no oxygen, because of a 5 degree temperature rise, due to our old friend carbon dioxide – a “heart attack” he described it as.
10m of sea rise is no biggie, in geological terms (I knew this, but it’s good to be reminded).
The pre-Holocene to Holocene was accomplished in three years because of a “change in the plumbing” (I’ll try to track down the paper they mentioned)
How it could have been better?
Well, we came for a “sage on the stage” presentation, and they were certainly sagacious. Not every event needs to be radically participatory or “democratic” – that said, an invitation to talk to the person next to you before it kicked off, or to devise questions in pairs before the Q and A kicked off would have helped. This is quibbling, however, about a well-done event. Did these geologists rock? Yes they did.
Disclaimer: MCFly has accepted a kind (and unsolicited) offer from Oxford University Press for copies of both The Goldilocks Planet and Professor Bill McGuire‘s “Waking the Giant” (Prof McGuire gave an earlier talk which, by all accounts, was even more depressing than the geologist/paleobiologist one described here).
These two books will need to be reviewed. Any volunteers?