Re: [geo] Michigan Scientists See Urgency for Negative Emissions | Climate Central

[Ronal W . Larson]

John, list  et al: Your diagram is helpful.   -- 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 https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.

Earth system restoration v2.xls
Description: MS-Excel spreadsheet

But I hope we can have further discussion on the time relationships between your 3 parts of carbon exchange (positive, neutral and negative).  I can almost believe the 2030 date in column M for 70% reduction in fossil emissions (combination of renewables and efficiency growing by about that much ).  That, assuming we are now emitting about 10 Gt C/yr,  would leave about 3 Gt C/yr emitted and about 1.5 Gt C/yr staying in the atmosphere (the remainder going mostly to the oceans).  The needed separate renewables and efficiency (carbon neutral) portions can be guesstimated now - and I will try to look that up.  Maybe a large carbon fee (don’t use the word  ”tax” in the USA) could pull off your 2030 date - but we certainly aren’t heading that way now. In columns I and J, you ask for removal “twice as fast as emitted”  in 2030 - or removal of about 2*3 = 6 Gt C/yr.    I will assume you meant twice initial (not final, after including oceans) removal, which would get us down to a needed carbon negativity of 2*1.5 = 3 Gt C/yr.  This to be done via the range of CDR options near the bottom rows - where the present removal is only a relatively small amount via afforestation and perhaps REDD+. For the latter two sinks, maybe 10’s or hundreds of Mt C/yr - but certainly not yet 1 Gt C/yr.   I think biochar is moving faster than any of the other main CDR approaches, but probably not yet even at 1 Mt C/yr. One beauty of the Oceans approach emphasized by Bhaskar is that the biomass growth can be much faster than on land - and there are enormous areas available.  But one needs to do something with that (temporarily) removed ocean carbon; transferring to land as biochar makes sense.  Afforestry takes much longer, because of lower photosynthesis conversion efficiency.  Biochar could rely mostly on annual or short rotation crops, but it will take considerable time to build up both the conversion complexes and the base of eventual soil depositories.    All this to urge reconsidering the column I-J entry.  Additionally, I think it would be easier to equate the two directions of carbon movement - rather than your present doubling.  So assuming only equality of positive and negative carbon annual flows, we can remove another factor of two and hope for a carbon negative flow of 1.5 Gt C/yr by 2030.  This I believe might be possible with afforestation - since Dr. Hansen has assumed something even larger (I recollect maybe 4 Gt C/yr?) before Hansen’s annual sequestration plateaus.  At 10 t C/ha-yr in 2030, one would need (1500 Mt C/yr)/(10 t C/ha-yr) = 150 Mha under active new forest management  (and much less if the “Bhaskar-oceans” are contributing in 2030).   This land area is not an outrageous number (although very large - and can grow) So far, I have modified John’s scenario two ways - so with his scenario,  the land area could be 2 or 4 times larger (I am trying for the smallest possible number in 2030.  Could John explain why he chose the word “double” in 2030?  I think it much easier to visualize that year when the positive and negative annual curves cross.  I am advocating that the choice for 2030 be based (for simplicity) on terms that leave the (huge) ocean influence out of the numerical aspirations.  To repeat - the computations should emphasize (as John’s do) what society does in Gt C/yr, not what is happening in the atmosphere (Gt C or ppm CO2), which is slower (because of ocean capture).   I started this small exercise thinking only about it having little chance - but have changed my mind based on the afforestation and ocean options John has postulated.  No existing biochar model comes close to doing this much by 2030.  Biochar will be an added “wrinkle” that assures use of the needed biomass also for energy - to be back-up for the aggressive non-dispatchable wind and solar carbon neutral options John is assuming.  Managing above ground biomass should not cause any loss of annual carbon negativity - since that can be balanced by biochar-caused out-year increased NPP. I wonder if anyone knows of a simple model that could further justify John’s numbers.  I have one in mind, but only know its outputs, not yet its inner workings.   It is important that we interested in both halves of geoengineering fill in more of the time history that John has (helpfully) hinted at above - especially emphasizing his key year 2030. Ron ps  -  just received today this site on forestry:  https://thinkprogress.org/planting-trees-climate-change-solution-3e5b6979561f#.kmnmhx7zd  and http://www.theenergycollective.com/edfenergyex/2386927/in-win-for-environment-court-recognizes-social-cost-of-carbon?utm_source=feedburner&utm_medium=email&utm_campaign=The+Energy+Collective+%28all+posts%29   On Aug 30, 2016, at 3:33 PM, John Nissen <johnnissen2...@gmail.com> wrote: Hi Bhaskar and everyone, I have drawn the attached diagram to include all the major interventions I think are required for climate restoration.  I have put a target of 2050, which I think could be achieved with a determined international collaboration, especially to save the sea ice.  (If the Arctic Ocean gets locked into a seasonally ice-free state, then severe climate change becomes inevitable and irreversible.) In order to actually halt anthropogenic global warming well below 2C by 2050, climate forcing has to be quickly reduced.  My rough calculations suggest that it needs to be halved by 2030 if it is to be near zero by 2050.  I assume that emissions can be reduced 70% by 2030 and that CDR will have grown such as to remove twice as much CO2 as being emitted by 2030.  Thus by 2030 the level of CO2 in the atmosphere should already be falling. I have put three basic means of CDR: increasing biomass as wood, putting carbon in the soil, and increasing biomass in the oceans: (i) Increasing biomass as wood requires afforestation and improved forest management (as Alan Page points out).  (ii) Putting carbon in the soil can be done with biochar or by growing plants with long or longer roots.  Food productivity can be increased at the same time.  (iii) Increasing biomass in the oceans can be done by ocean fertilisation to promote photosynthesing algae, such as diatoms, which then promote the whole food chain while removing CO2 from the water and oxygenating it.  This has the potential to at least double food from the sea for human consumption.  CO2 can also be drawn down in large quantities with kelp farming.   Reductions in methane, black carbon and other climate forcing agents are also required, to achieve near zero climate forcing by 2050.  Diatoms with nutrients can be spread over areas of methane emissions to promote methanogens.  Much black carbon is coming from tundra fires which can be suppressed. Restoring the Arctic involves increasing the albedo, and the target might be, by 2050, to return the snow and ice to the levels they were in the 1980s before both started retreating exponentially.  BTW, Sev Clarke has mentioned to me several other interventions, but the diagram is not intended to cover all possibilities and I didn't want it to become too complex. Cheers, John On Fri, Aug 26, 2016 at 1:46 PM, M V Bhaskar <bhaskarmv...@gmail.com> wrote: Ron     <snip> -- 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 https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.