Thanks John Please keep me in the loop on your thoughts on combining biochar and soil mineralisation with rock dust. We need all the sensible ideas we can get.
Regarding the potential benefits of biochar, I tried to include potential benefits for any technique where they were suggested or reported, under the heading of 'side effects'. And in the discussion I suggested that where positive side effects could be demonstrated it might make a technique more attractive. This may well apply to biochar (although the benefits have yet to be consistently demonstrated and quantified - as far as I could tell), and I particularly suggest that biochar might be the optimum route for sustainable biomass where decentralised energy is needed, and where geological stores/ CO2 pipelines are far distant, or exhausted. Given a limit to sustainable biomass production, and competition for theat biomass: I agree we need to use multi-criteria assessment to decide the optimum distribution of use. However given such a limit, then the net carbon benefit might have to be weighted highly in any such assessment. I also broadly agree with you regarding the near term need for NETs, though my estimates would suggest that getting back to 350 anytime before the end of the century will be a push. Best wishes Duncan On Sep 21, 11:53 pm, John Nissen <[email protected]> wrote: > Hi Duncan, > > Thank you for your tremendous effort to describe all the available CDR/NET > technologies together, in a comprehensive way such to allow a comparison. > > I've been discussing biochar and rock crushing with Ron Larson and Oliver > Tickell; we concluded that there was scope for a combined method, which > could be scaled up to remove many gigatonnes of carbon per year at low > cost. (We've used weight of carbon rather than CO2 in our calculations.) > > I think you should have a separate column for benefits, because biochar has > several: it improves soil, reduces need for fertiliser (thus avoids > considerable emissions), reduces water requirements, and is applicable in > poorer countries for improved, productive and profitable farming. > > It is now recognised that ocean acidification could be far more serious and > more urgent than hitherto suggested, such that we'd need CDR to get the > atmospheric level of CO2 below 350 ppm within twenty or thirty years. For > the first ten years, we'd have to build up CDR such as to cancel out global > CO2 emissions. Then we'd have to ramp up CDR a bit further to actually > reduce the CO2 level. I would like to see biochar take a significant role - > but it would require education and infrastructure projects to mobilise > farmers worldwide. > > Cheers, > > John > > -- > > On Wed, Sep 21, 2011 at 12:11 PM, Duncan McLaren <[email protected] > > > > > > > > > wrote: > > Group members may find my assessment of negative emissions > > technologies (NETs) of interest. > > > The full report runs to about 100 pages, and can be found at > > >https://sites.google.com/site/mclarenerc/research/negative-emissions-... > > > A summary version written for Friends of the Earth (England, Wales and > > NI) will be published online later today. > > > The assessment covers a wide range of NETs, but not SRM techniques. It > > considers capacity, cost, side effects, constraints, technical > > readiness, accountability and more for about 30 options. > > > I'd be delighted to get feedback and comments. > > > regards > > Duncan > > > -- > > You received this message because you are subscribed to the Google Groups > > "geoengineering" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group at > >http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
