Graph of the Day: CO2 and Extinction Events

January 31, 2011

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Peter Ward’s book, “Under a Green Sky”, kept me awake for several hot summer nights a few years ago.  It’s a description of the ancient greenhouse event that kicked off the “Great Dying” – the Permian Extinction, the most catastrophic period in the planet’s history, a near total wipeout of all species.  A large body of evidence has been accumulating that most of the extinction events in the planet’s history have followed greenhouse events.

I wrote to Ward to find out more, and he sent me the graph above, which is eloquent.

You can see Ward interviewed on the NOVA program I posted last week, and his  piece in Scientific American is useful and informative.

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6 Responses to “Graph of the Day: CO2 and Extinction Events”


  1. Unlike previous extinction events, other human influences (mostly pollution, resource restriction and restrictions to species movement with climate zonal shifts) make the problem even worse. Even without climate change, biodiversity loss is terrible already.. I don’t know how we could prevent species loss as climate changes without addressing many other impacts as well.

  2. otter17 Says:

    Wow, the CO2 rate of change during our era seems to be the fastest in the record. Also, our current increase in CO2 over pre-industrial levels seems to be on par with the jump before the Paleocene Thermal Extinction (PTE).

    Have we already committed the planet to an extinction something like the PTE?

    Is there any indication that the CO2 rate of change can affect the severity of an extinction event? It makes sense as a hypothesis.

    What are the red bars supposed to represent? Error bars of some sort, or just markers for each extinction event?

    What is the white box near time zero? Does it imply that we are expected to stabilize at roughly 1000 ppm of CO2?

    So many questions. A thought-provoking Graph of the Day for sure… I’ll be sure to keep this one bookmarked.

  3. greenman3610 Says:

    The cautionary note on the graph is that the time spans are so inconcievably long that it necessarily leaves a lot out.
    The current increase is probably about as rapid as has ever occurred. That’s one of the big question marks – the planet changed 4 to 5 degrees between ice ages, but that transition, relatively rapid geologically, still takes 5 to 10 thousand years.
    We’ll do it in 200 or so, unless we start taking action now.
    Consequences unknown – but the paleo record indicates there are as yet unknown feedbacks at higher temps, so beware.
    Red bars are markers, not error bars, as far as i can tell.
    I think the white box is just an arbitrary terminal point.
    recommend reading “Under a Green Sky”.

  4. otter17 Says:

    Peter Ward seems like a great writer and expert in his field. I’ll have to check my library.

    Thanks so much for the answers.

    This graph runs counter to some of the comments I hear about climate science’s inability to provide past examples or experiments that show CO2’s ability to change the climate with any ill effect.

  5. greenman3610 Says:

    Climate science is based more on the paleo record than almost anything else.
    Nature has run most of these experiments in the past. Unless the laws of physics have changed, the planet will respond to higher GHGs the way it always has.

    see

    and check Andrew Dessler’s opening statement here – uses a little math, but
    makes the point about climate science and the evidence of the past

  6. otter17 Says:

    Sweet. In-depth information beats a one-off denial statement any day. And I say bring on the math.


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