Or simply CRS (Carbon Removal and Storage). A few years back when this group came up with the names SRM and CDR, I argued for CRS, reasoning that any CO2 removal method has to be accompanied by storage as a truly workable carbon sequestration strategy. many cheers, -Ning
On Monday, November 18, 2013 5:59:10 PM UTC-5, kcaldeira wrote: > > Folks, > > The question about whether biochar is a CDR technique and therefore > "geoengineering" raises some interesting issues. > > Carbon Dioxide Removal (CDR) techniques involves to processes that are in > principle separable: > > 1. Carbon dioxide removal from the atmosphere (or oceans) > 2. Storage of that carbon in a long-lived pool. > > Carbon can be removed from the atmosphere using biological strategies > (e.g., land plants, phytoplankton) or chemical strategies (e.g., direct air > capture, accelerated chemical weathering). > > Carbon so removed must then be stored in a long-lived reservoir. Carbon > can be stored in a reduced form (e.g., biochar, living forests) or in an > oxidized form (e.g., CO2 injected in geologic reservoirs, Fe-fertilized > biomass that has oxided into dissolved inorganic carbon in the deep ocean). > > Carbon stored in an oxidized form can be largely in the form of molecular > CO2 (perhaps dissolved) or can be part of another compound such as CaCO3 > (perhaps dissolved). > > What makes something CDR approach is a system property (i.e., air capture > that vents back to the atmosphere is not a CDR approach; geologic CO2 > storage without air capture is not a CDR approach; but put the two together > and you have a CDR approach). > > On this taxonomy, I would consider biochar as a way of storing reduced > carbon for long periods of time. Under this interpretation, biochar could > be part of a CDR system, but as a process in-and-of-itself, biochar is an > approach for carbon storage. Biochar does no carbon dioxide removal, so > cannot itseld be a CDR technique. > > Therefore, it may make sense to talk about biochar as a carbon dioxide > storage approach. As part of a system of biological carbon capture by land > plants and storage using biochar, biochar can be part of a CDR system, but > biochar itself is not a CDR system. > > Maybe we should be talking about CDRS (Carbon Dioxide Removal and Storage) > instead of CDR. We should then specifiy both the Carbon Dioxide Removal > (CDR) approach and the Storage (S) approach. > > Biochar is an S approach, not a CDR approach. > > Best, > > Ken > > _______________ > Ken Caldeira > > Carnegie Institution for Science > Dept of Global Ecology > 260 Panama Street, Stanford, CA 94305 USA > +1 650 704 7212 [email protected] <javascript:> > http://dge.stanford.edu/labs/caldeiralab > https://twitter.com/KenCaldeira > > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/groups/opt_out.
