A Few Things Ill Considered

Turn CO2 into Rock

Posted by coby on November 17, 2008
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As the CO2 in the atmosphere continues to climb, already at a dangerous level, and the argument about doing something about it seems to have only just begun in the power circles, I fear that actively removing it is rapidly becoming an imperative.

But is this doable?

I don’t know…I sure hope so. And not just for climate change, but also for ocean acidification. Removing CO2 directly from the atmosphere is really a form of geoengineering and part of a principal that I find extremely worrisome. I would have counted myself deadset against geoengineering of any sort before reading an essay posted here, but written by H.E.Taylor. I guess the boiled-down message there is like it or not, we are already deeply involved in the geoengineering business.

So, coming from that and being an optimist, I read the following with a little hope for what may be possible afterall.

A breaking study indicates that 4 billion tons of carbon dioxide a year could be locked up in rock formations that cover half of Oman–finally putting a dent in global greenhouse gases. And the same principle could be transferred to rock formations in shallow seas.

The article is about work by Columbia University geologist Peter Kelemen who has been studying peridotite:

a highly-reactive rock that covers about half the landscape of Oman, and appears at scattered locations worldwide. The rock naturally reacts with carbon dioxide (CO2), removing it from the air to form limestone and other carbonates.

So after capturing CO2 at sources like coal-fired power plants, rather than pump it into big pools underground and praying it does not ever escape somehow, we could turn it into rock! Of course this is a natural part of the carbon cycle, but what Kelemen is claiming is a way to accelerate this process 100,000 fold. This is a big number but necessarily so considering the time scale of natural conversion of CO2 into things like limestone.

Go have a read for yourself and maybe allow me a few minutes of optimism before using the comments to draw out the myriad devils that must surely be lurking somewhere in those missing details!

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Comments

  1. #1 gborun
    November 17, 2008

    Forever: rig some nanobots to make diamond.
    A years fuel would make a 2 cubic km diamond.
    Or Diamond beach sand – high conductivity might burn your feet on a hot day but.

  2. #2 Hank Roberts
    November 17, 2008

    Er …

    http://www.offshore-mag.com/display_article/23172/120/ARTCL/none/none/2/MIDDLE-EAST-GEOLOGY-Why-the-Middle-East-fields-may-produce-oil-forever/

    The rift zone and magma chamber are magnified. Note the cumulative ultramafic and gabbroic rocks inside the chamber.
    http://images.pennwellnet.com/ogj/images/off/55046001.gif

    “… The location and orientation of hydrocarbon fields appear to be controlled by and related to subduction and rifting activities. The formation of hydrocarbons are due to the chemical processes which take place, even today, within the subduction/rift zones, and deep into the basement.

    The carbon and hydrogen, necessary for the formation of hydrocarbons, can originate from organic compounds, located in subducted sedimentary rocks, and from the dissociation of carbonates (CaCO3 ), and the reduction of carbon dioxide (CO2 ) and water (H2O) that seeps into subduction zones, or deep into rifts and fractures.

    Furthermore, CO2 can be released from cracked olivine and pyroxene in lithospheric and basaltic rocks. The reduction of CO2 to carbon (C), and H20 to hydrogen (H2) is probably catalyzed by oxidizing ferrous iron (Fe+2 ) present in mafic minerals to ferric iron (Fe+3 ). The combination of C and H2, at 300-500°C, has formed paraffinic and naphthenic compounds (both present in the oils of the Middle East)….”

    Pump CO2 into a rift zone, shall we?

    Why not? What could possibly go wrong?

    Or as someone on another blog put it, first we pay them to pump the petroleum out; then we pay them to pump the CO2 in ….

    Then we do it again? Ah, the irony abounds.

  3. #3 Mike Kaulbars
    November 17, 2008

    And of course this would be a short term stop gap to buy us some time … any idea when we hit ‘Peak Peridotite’?

  4. #4 coby
    November 17, 2008

    “peak peridotite” LOL, that had occured to me as well. Also the problem of transporting CO2 from where ever it is produced to where ever the suitable deposits are.

    But don’t we need to think harder and see if these problems can’t be solved before hand waving them away.

    I think these things may become necessary regardless of how fast we can return to collective sanity, but not instead of it. Production needs to drop ASAP, but it is not looking like it will be ASAP enough.

  5. #5 Kiwiiano
    November 18, 2008

    Quoting gborun: “Or Diamond beach sand – high conductivity might burn your feet on a hot day but.”
    Heaven help anyone lighting a driftwood fire on a summer’s evening!
    I still think it will be more productive to bypass the dinojuice entirely, just leave it in the ground, and concentrate on ramping up algae bioreactors. It’s pure liquid solar power, with no damage to the biosphere at all.

  6. #6 paul
    November 18, 2008

    “As the CO2 in the atmosphere continues to climb, already at a dangerous level”…

    “already”?

    Can you tell me what observations back-up your statement that the current levels are “dangerous”, and what danger they pose, please?