Ken (with ccs) : Thanks for attaching the Archer paper for which you were a co-author. The paper looks well done - and I think it great that the team was able to get nine models working on the same scenarios - especially on a voluntary, unfunded basis. We will all look at such a paper for our own perspectives - the following is only from a biochar proponent's perspective. I understand that this paper had no intention of addressing this list's topics - either Geoengineering or Biochar; I am simply trying to draw as much out of the paper as I can in hopes there is information here to help with better modeling of Biochar. Apologies if I am missing a connection in this paper to other types of Geoengineering - and apologies for writing so much - this has admittedly little connection to Geoengineering (but I am trying to see if there aren't some.
1. The main relationship of the paper to the topic of Geoengineering is through the fourth variable - vegetation, featured in the sequentially last addition in both the 1000 and 5000 Gt scenarios by three teams (UVIC , MPI-UW, and Climber). As I want to alert people in the Biochar community , I quote from the paper just on the biomass/vegetation portions with the _*bold underlining*_ showing the reasons. a. UVIC2.8 is the University of Victoria Earth System Climate Model,........ The _*terrestrial*_ carbon model is a modified version of the MOSES2 land surface model and the TRIFFID dynamic *_vegetation_* model (Meissner et al. 2003)." [Meissner KJ,Weaver AJ, Matthews HD, Cox PM. 2003. The role of land surface dynamics in glacial inception: a study with the UVic Earth System Model. Clim. Dyn. 21:515–37 ] _*Ocean*_ carbon is simulated by means of ....... a marine ecosystem model solving prognostic equations for nutrients, phytoplankton, zooplankton, and detritus (Schmittner et al. 2008). [Schmittner A, Oschlies A, Matthews HD, Galbraith ED. 2008. Future changes in climate, ocean circulation, ecosystems, and biogeochemical cycling simulated for a business-as-usual CO2 emission scenario until year 4000 AD. Glob. Biogeochem. Cycles 22:GB1013] *[RWL: The best contacts seem to be co-authors Eby and Matsumoto at Univ. Victoria * b. _*MPI-UW*_ (Mikolajewicz et al. 2007) ........ "HAMOCC3 *_ocean_* biogeochemistry (Winguth et al. 1994) " [Winguth AME, Heimann M, Kurz KD, Maier-Reimer E, Mikolajewicz U, Segschneider J. 1994. El Nino- Southern Oscillation related fluctuations of the marine carbon cycle. Glob. Biogeochem. Cycles 8:39–65]. "The *_land biosphere_* is simulated using the dynamic _*vegetation*_ model LPJ (Sitch et al. 2003). ..".. [Sitch S, Smith B, Prentice IC, Arneth A, Bondeau A, et al. 2003. Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model. Glob. Change Biol. 9:161–85] *[RWL: A cooperative effort between Max Plank and Univ. of Wisconsin - apparently co-author Brovkin is key person.]* c. " *_CLIMBER-2_* consists of ..........a *_terrestrial biosphere _*model (VECODE), an oceanic biogeochemistry model, and a phosphate-limited model for marine biota (Ganopolski et al. 1998; Brovkin et al. 2002, 2007)." ..... [Ganopolski A, Rahmstorf S, Petoukhov V, Claussen M. 1998. Simulation of modern and glacial climates with a coupled global model of intermediate complexity. Nature 371:323–26] [Brovkin V, Bendtsen J, Claussen M, Ganopolski A, Kubatzki C, Petoukhov V. 2002. Carbon cycle, *_vegetation_* and climate dynamics in the Holocene: Experiments with the CLIMBER-2 model. Glob. Biogeochem. Cycles 16:1139 [Brovkin V, Ganopolski A, Archer D, Rahmstorf S. 2007. Lowering of glacial atmospheric CO2 in response to changes in oceanic circulation and marine biogeochemistry. Paleoceanography 22:PA4202] *[RWL: Archer and Brovkin seem active with this model. **See an open-access article from 2008: http://geosci.uchicago.edu/~archer/reprints/archer.2008.tail_implications.pdf] * * **RWLQ1s: Three is correct (other 6 models never included vegetation? Any other recommended references for biomass modeling of this type? (see more references below also) * 2. The following quotes are what was said about the vegetation results seen in Figures 3d, and 4d (with interspersed comments by RWL): "The vegetation feedback operates on annual to century timescales, which is substantially faster than the ocean feedbacks. The productivity of terrestrial plants increases instantaneously *[RWL2a: the graphs don't seem instantaneous; explanation? what was time step for each team?]* with elevated atmospheric CO2 concentration because a physiological response of the plant stomata leads to higher water-use efficiency and a consequent increase in plant biomass (Denman et al. 2007). [Denman KL, Brasseur G, Chidthaisong A, Ciais P, Cox PM, et al. 2007. Couplings between changes in the climate system and biogeochemistry. In Climate Change 2007: The Physical Science Basis, ed. S Solomon, D Qin, M Manning, Z Chen, M Marquis, et al., pp. 499–587. Cambridge, UK: Cambridge Univ. Press] "Enhanced respiration of plant tissues and accelerated decomposition of soil organic matter owing to elevated temperatures counteract this effect, but a net result of projected changes in CO2 and climate is an increase of the land carbon storage in *_most_* vegetation models (Cramer et al. 2001, Friedlingstein et al. 2006). [Cramer W, Bondeau A, Woodward FI, Prentice IC, Betts RA, et al. 2001. Dynamic responses of global terrestrial ecosystems to changes in CO2 and climate. Glob. Change Biol. 7:357–73] [Friedlingstein P, Cox P, Betts R, Bopp L, von Bloh W, et al. 2006. Climate-carbon cycle feedback analysis: Results from C4MPI model intercomparison. J. Clim. 19:3337–53] *[RWLQ2b: Increase in "most" but not in all vegetation models? These three all quite close for the 1000 GT case - but quite varied for 5000 GT case.] * "This is reflected in Figures 3 and 4. A presence of vegetation feedback in the simulations substantially reduces an airborne CO2 fraction, especially during the first hundred years. After this period, the ocean carbon uptake gains control over the atmospheric CO2 concentration because of the much larger buffering capacity of the ocean in comparison with the land. Although these results are in line with expected long-term vegetation feedback (Bala et al. 2005, Plattner et al. 2008), many *_uncertainties_* in the representation of long-term land biogeochemistry make the land feedback story more *_comprehensive_*. [Bala G, Caldeira K, Mirin A, Wickett M, Delira C. 2005. Multicentury changes to the global climate and carbon cycle: Results from a coupled climate and carbon cycle model. J. Clim. 18:4531–44] [Plattner G-K, Knutti R, Joos F, Stocker TF, von Bloh W, et al. 2008. Long-term climate commitments projected with climate-carbon cycle models. J. Clim. 21:2697–710] *[RWLQ2c: I'd like to hear more on the last clause:"...uncertainties....make.....more comprehensive."]* "Modeling of soil carbon dynamics is still in its infancy; *_many important_* mechanisms, the priming effect of the addition of fresh organic material to the soils (Fontaine et al. 2003) and processes of anaerobic decomposition of organic matter, for example (Frolking et al. 2001), are_* not yet accounted*_ for in the coupled global models." [Fontaine S, Mariotti A, Abbadie L. 2003. The priming effect of organic matter: a question of microbial competition? Soil Biol. Biochem. 35:837–43] [Frolking S, Roulet NT, Moore TR, Richard JPH, Lavoie M, Muller SD. 2001. Modeling northern peatland decomposition and peat accumulation. Ecosystems 4:479–98] *[RWLQ2d: And similarly not yet Biochar, presumably. I wonder about the term "many important".* *It appears that the impact of added charcoal is to quite greatly add to root, microbe and fungal mass. Maybe a missing equal biomass below ground not being counted?]* "Nitrogen and phosphorus balance is ignored in most of the models (Reich et al. 2006), and changes in carbonate storages in dryland soils are neglected (Lal et al. 2000). Models of vegetation (forest) dynamics on a global scale are extremely simplified and difficult to validate because of the long timescales involved (Purves & Pacala 2008). " [Reich PB, Hobbie SE, Lee T, Ellsworth DS,West JB, et al. 2006. Nitrogen limitation constrains sustainability of ecosystem response to CO2. Nature 440:922–25] [Lal R, Kimble JMH, Eswaran H, Stewart BA, eds. 2000. Global Climate Change and Pedogenic Carbonates. Boca Raton, FL: CRC Press] [Purves D, Pacala SW. 2008. Predictive models of forest dynamics. Science 320:1452–53] *[RWLQ2e: No specific comment -but can add that Biochar is reported to reduce N2O and phosphorous releases.]* "Finally, changes in the land carbon uptake due to future alteration of land use by humans are almost impossible to foresee. All these limitations of the land model assumptions make the simulations of the land carbon response to the CO2 pulse presented here illustrative rather than predictive." *[RWLQ2f: Per Peter Read - Biochar (an intentional anthropogenic variation in the carbon cycle) can probably be a bigger change than anything else listed.] 3. Notes about the figures: *a. The three"instantaneous" draw-down values for the 1000 Gt case are between 100 and 120 ppmv (around 250 Gt?) - before year 50. It is not clear the breakdown between plant, soil, and ocean contributions. Hopefully the detailed data behind these graphs are available somewhere. b. The biggest change I see is that the 3 models are much more similar for the 1000 Gt vegetation case than the 5000 Gt vegetation case. Understanding these differences looks important c. It appears that one of the three case graphs are missing in Fig 1 for each of the three vegetation cases. Only two curves are shown, so it is not possible to generate Figs 3 and 4 from Fig 1. Hopefully it will b possible to obtain the raw data. d.. I think that the upper right part of Fig 1 has an incorrect labeling of the three cases (solid and dotted not consistently labeled between the 1000 and 5000 cases (should be a reversal, I believe.) *4. Summary:* I doubt that the ongoing Biomass discussion between Peter Read and Mike McCormick will be illuminated at all by this paper. But 3 of the 9 models in this paper have apparently made very different but probably useful assumptions about the impact of excess carbon dioxide on Biomass' (and therefore Biochar's) ability to withdraw CO2 from the atmosphere. There seem to be a multitude of good papers to now review. I thank Ken for bringing this paper to our attention. If anyone has comments to make on any of the paper's Biomass citations (or good missing ones - for modeling purposes), they would be appreciated.] Ron Ken Caldeira wrote (yesterday, giving the paperI am commenting on, that can also be found at http://geosci.uchicago.edu/~archer/reprints/archer.2009.ann_rev_tail.pdf): > Be aware that that formulation of Vaughn and Lenton is a > simplification and that 20% asymptotic value and 40% is probably a > better estimate for cumulative releases on the scale of conventional > fossil fuel resources. > > See attached paper for discussion. > > ___________________________________________________ > Ken Caldeira > > Carnegie Institution Dept of Global Ecology > 260 Panama Street, Stanford, CA 94305 USA > > [email protected] <mailto:[email protected]>; [email protected] > <mailto:[email protected]> > http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab > +1 650 704 7212; fax: +1 650 462 5968 > > > > On Sat, Nov 21, 2009 at 10:40 AM, Alvia Gaskill <[email protected] > <mailto:[email protected]>> wrote: > > From Lenton and Vaughn (2009): > <snip rest as not being pertinent to either modeling or early vegetation carbon sequestration issues> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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