Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

Buy individually or both books together. Delivery is free!


powered by Surfing Waves




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




    •  
      CommentAuthorfostertom
    • CommentTimeJul 8th 2020 edited
     
    •  
      CommentAuthordjh
    • CommentTimeJul 8th 2020
     
    Sounds like it's seen as a good idea. As I understand the chemistry, it essentially transfers CO2 from the atmosphere to dissolved in the oceans, and that's simply speeding up a natural process. But I thought CO2 dissolved in the ocean was the cause of ocean acidification, and therefore something we are seeking to reduce rather than increase. So I'm confused.
    •  
      CommentAuthorfostertom
    • CommentTimeJul 8th 2020 edited
     
    I think the rock carbonises on the land to CaCO3 aka limestone, which is what washes into the sea, not CO2 which first reacts with H20 to produce H2CO3 Carbonic Acid?
    •  
      CommentAuthordjh
    • CommentTimeJul 8th 2020
     
    Posted By: fostertomI think the rock carbonises on the land to CaCO3 aka limestone, which is what washes into the sea

    No, the rock starts out as a carbonate CaCO3 (or a silicate) and that is broken into Ca and HCO3 ions by the addition of rainwater and CO2 from the atmosphere. The ions are washed into the sea where the CaCO3 and CO2 reform, but with the CO2 dissolved in the water.

    See https://en.wikipedia.org/wiki/Enhanced_weathering
  1.  
    You spread magnesium silicate (olivine or similar) on the land where it biologically carbonates with atmospheric CO2 and water, to form bicarbonate HCO3-, which washes down to the sea. The sea beasties turn that into calcium or magnesium carbonate, then its never seen again.

    It's been suggested over many years, the issues include the environmental impact of quarrying the mineral in the limited places where it outcrops and trucking it round the country to farms. And then you are messing with the soil chemistry which will have complex ecological effects, probably some undesirable.

    Plus, as with all geoengineering and sequestration, it's expensive and somebody has to pay for it, and it's not clear who that customer would be.

    Edit to add: it's trying to replicate the carbonate-silicate cycle which is how the Earth naturally regulates atmospheric CO2. You spread silicates rather than carbonates on the land, as that way there's a net removal of CO2. If you spread carbonate on the land there's just a net transfer of carbonate and CO2 into the sea. CO2 dissolved in the sea causes acidification which inhibits the organisms who would otherwise be locking carbon away in carbonate.
    • CommentAuthorEd Davies
    • CommentTimeJul 9th 2020 edited
     
    For context, they say this would remove about 2 Gt/year of CO₂ (i.e, about 0.545 Gt/year of carbon). Humans are currently emitting somewhat north of 40 Gt/year of CO₂ (10.9 Gt/year of carbon).

    https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere#Anthropogenic_CO2_emissions
    •  
      CommentAuthorfostertom
    • CommentTimeJul 9th 2020 edited
     
    Where did you get the 2Gt figure Ed? Not insubstantial at that - gd to have multiple means, not just one big one.
    Posted By: WillInAberdeenas with all geoengineering and sequestration, it's expensive and somebody has to pay for it, and it's not clear who that customer would be
    If it's true about agricultural benefit 'more than paying for it' ...

    Posted By: WillInAberdeenAnd then you are messing with the soil chemistry which will have complex ecological effects, probably some undesirable
    Yes, that's just the kind of subtle downfall that's universally ignored, uninvestigated by sponsors - corporations, policy-making govts - in brave new schemes, but which simply dig the hole deeper.
    • CommentAuthorEd Davies
    • CommentTimeJul 9th 2020
     
    Posted By: fostertomWhere did you get the 2Gt figure Ed?
    From the Guardian article you linked:

    The analysis, published in the journal Nature, estimates that treating about half of farmland could capture 2bn tonnes of CO2 each year, equivalent to the combined emissions of Germany and Japan.
  2.  
    The Nature article mentions 0.5-2 Gt/a at $80-180/tCO2. Would involve 3% of national energy supply to grind up the silicates and 2.5billion subsistence farmers to spread them. There's currently a lack of any long term trials to check for benefits/drawbacks.
Add your comments

    Username Password
  • Format comments as
 
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press