Mike et al., I don't think anyone is asking mineral weathering to singlehandedly solve the problem, though the fact that it can and will naturally solve the problem given enough time means it does have the proven capacity to do so, unlike any other CDR scheme I am aware of. How much accelerated weathering we do does largely come down to extraction, processing, and movement of mineral mass. Yes, Gt's of CO2 mitigation does require Gt's of mineral, but why is this necessarily a showstopper if we fail to stabilize CO2 by other means? We currently extract about 2.5 Gt of minerals/yr. Is it unthinkable that we wouldn't/couldn't double or triple this in the interest of helping to stabilize air CO2, climate and ocean acidity? Or would you prefer to impact vastly larger land areas and potentially disrupt food and fiber production by employing IPCC-endorsed BECCS or afforestation? All methods of air CO2 management have benefits, costs, impacts, and tradeoffs. Let's hope that we invest in the research to well understand these for all of the CO2 management options available, and that we then make rational decisions on their deployment (in time) based on this info. Given the decisions and endorsements made so far, I'm not holding my breath. Hence, looking forward to that private resilience session in Paris. Greg
>________________________________ > From: Mike MacCracken <mmacc...@comcast.net> >To: Geoengineering <Geoengineering@googlegroups.com> >Cc: Andrew Lockley <andrew.lock...@gmail.com>; Bill Stahl <bstah...@gmail.com> >Sent: Monday, January 26, 2015 5:09 PM >Subject: Re: [geo] Re: Energy Planning and Decarbonization Technology | The >Energy Collective > > > Re: [geo] Re: Energy Planning and Decarbonization Technology | The Energy Collective Here is another way to think of the amount of mass being talked about. The global average per capita use of carbon today is of order 9. GtC/yr/7B people, so about 1.3 ton per person of carbon. Multiply by 3.67 to get to CO2, and it is about 5 t CO2 per person. Would olivine be an equal mass (or a bit more to match mole to mole)? That is a lot of olivine—and for every person on Earth to deal with present emissions—even if this is off by a factor of a few!!! Every person on Earth—not just everyone on coastlines in NJ or the US or the world. This is why we have to get global emissions down down, down and then also be doing something like this. Mike On 1/26/15, 5:36 PM, "Andrew Lockley" <andrew.lock...@gmail.com> wrote: Yes, placing olivine accurately is almost the exact equivalent of vacuum dredging, but in reverse. > >You could dump it with a huge Panamax class vessel, but it you'd end up with >the drop too far from the shore, and probably too bunched up, too. > >With a smaller ship, like a dredger, you'd get the distribution you need. >Added to which, the materials handling costs are going to be almost exactly >right, because with dredging you're pulling material out of the sea in an >arbitrary but nearshore location, and moving it to the nearest port with a >rail head where you can get rid of it. > >It's olivine backwards. > >A > >On 26 Jan 2015 22:24, "Bill Stahl" <bstah...@gmail.com> wrote: > >I hesitate to add to what is already a leviathan of a thread... but here goes. >>Assuming a carbon price were in effect, could coastal governments and >>landowners offset the cost of beach enhancement & sand replacement with >>CO2-sequestering sand? It would not have to optimally efficient to be >>substantial. >>On the face of it, getting permitted to use olivine on beaches seems a huge >>hurdle, but there is a already a tremendous amount of stirring-up of shallow >>coastal waters, budgeted and permitted. Transportation has already been >>arranged. Based on my familiarity of the Jersey Shore, coastal towns throw >>enough money at replacing sand that will quickly erode away, so why not put >>it to some long-term use? (Perhaps Atlantic City's unemployed croupiers can >>be sent out stirring the beaches). I have no idea how to calculate the >>potential scale, but perhaps this has already been done. >> >>Convince homeowners' associations to link CDR to property values and you've >>harnessed an unstoppable force... >> >>And is dredging relevant here? Talk about mass-handling. >> >> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to geoengineering+unsubscr...@googlegroups.com. To post to this group, send email to geoengineering@googlegroups.com. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to geoengineering+unsubscr...@googlegroups.com. To post to this group, send email to geoengineering@googlegroups.com. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
