With so much uncertainty surrounding this small indirect carbon cycle effects of SRM, I would not bother about monetizing calculations at this time. Bala
On Wed, Apr 29, 2020 at 5:49 PM Andrew Lockley <andrew.lock...@gmail.com> wrote: > That is indeed correct, but there is no accepted approach to financialise > temporary radiative forcing. The effect on the carbon cycle would give a > way to create a business model for SRM operations - as described in the > papers I've sent. > > Andrew > > On Wed, 29 Apr 2020, 12:32 Govindasamy Bala, <bala....@gmail.com> wrote: > >> Andrew, >> Technically, carbon and radiative forcing are equivalent to each other. >> There are standard formulas to go from carbon to radiative forcing. >> Bala >> >> On Wed, Apr 29, 2020 at 4:45 PM Andrew Lockley <andrew.lock...@gmail.com> >> wrote: >> >>> The reason that the CDR aspect is significant is that there is already a >>> way to monetise this, through voluntary carbon offsets. This was first >>> suggested by Sargoni and I >>> https://www.researchgate.net/publication/284534197_Environment_Policy_Solar_Radiation_Management_and_the_voluntary_carbon_market >>> >>> There's no such scheme available to monetise radiative forcing >>> >>> Andrew >>> >>> On Wed, 29 Apr 2020, 11:43 Govindasamy Bala, <bala....@gmail.com> wrote: >>> >>>> Andrew, >>>> >>>> "Are you saying that SRM effect on the carbon cycle still appears to be >>>> the net removal of Atmospheric CO2?" >>>> >>>> Yes, that is what the models say since this first 2008 PNAS paper by >>>> Matthews and Ken on this topic which showed that CO2 levels would be lower >>>> in SRM scenarios. This work finds that CO2 is reduced from 900 ppm to about >>>> 800 ppm in the atmosphere by 2100 in the A2 scenario. Not a lot as CO2 >>>> forcing goes up only logarithmically with CO2 concentration >>>> >>>> https://www.pnas.org/content/104/24/9949 >>>> >>>> There would be of course large uncertainties but I think the >>>> qualitative result would not change across models. I would not go that far >>>> to say it is a CDR technique. I would rather say it is a secondary benefit >>>> or a co-benefit. >>>> >>>> Bala >>>> >>>> On Wed, Apr 29, 2020 at 1:42 PM Andrew Lockley < >>>> andrew.lock...@gmail.com> wrote: >>>> >>>>> So, to confirm: >>>>> Are you saying that SRM effect on the carbon cycle still appears to be >>>>> the net removal of Atmospheric CO2? >>>>> >>>>> If so, SRM can legitimately be used as a CDR technique. It may >>>>> therefore be eligible for Carbon credits, as per this paper. >>>>> https://journals.sagepub.com/doi/abs/10.1177/1461452916630082 >>>>> >>>>> On Wed, 29 Apr 2020, 08:56 Govindasamy Bala, <bala....@gmail.com> >>>>> wrote: >>>>> >>>>>> Andrew, >>>>>> >>>>>> You are absolutely right that "In situations where plants don't >>>>>> remain to decomposition (agro forestry), there will be a loss of NPP" >>>>>> >>>>>> Stock changes between two time periods are basically the integral of >>>>>> the net fluxes between the two time periods. In a warming scenario, there >>>>>> is net outward flux (and stocks decline) because the integrated >>>>>> respiratory >>>>>> fluxes more than the integrated in flux of NPP. In SRM scenario, >>>>>> integrated >>>>>> net flux is positive because the integrated respiratory fluxes are >>>>>> smaller >>>>>> than integrated in flux. >>>>>> >>>>>> Best, >>>>>> Bala >>>>>> >>>>>> On Wed, Apr 29, 2020 at 12:30 PM Andrew Lockley < >>>>>> andrew.lock...@gmail.com> wrote: >>>>>> >>>>>>> If the incoming flux decreases, the stock will reduce. To counter >>>>>>> this, the outgoing flux must decrease by as much, or more. What is this >>>>>>> corresponding decrease in the outward flux? >>>>>>> >>>>>>> Is it that decomposition of leaf litter, etc. is slowed by cooler >>>>>>> and drier conditions? >>>>>>> >>>>>>> In situations where plants don't remain to decomposition (agro >>>>>>> forestry), what will be the effect? Your results imply a loss of NPP. >>>>>>> >>>>>>> Andrew >>>>>>> >>>>>>> On Wed, 29 Apr 2020, 07:11 Govindasamy Bala, <bala....@gmail.com> >>>>>>> wrote: >>>>>>> >>>>>>>> Andrew, >>>>>>>> >>>>>>>> This is no contradiction between the Keith et al's commentary and >>>>>>>> this paper. Keith et al.'s paper is about stocks and this JGR paper is >>>>>>>> about the rate of flow of carbon between the atmosphere and the land >>>>>>>> biosphere (flux). The stocks and fluxes can behave very differently. >>>>>>>> The >>>>>>>> cooling caused by SRM reduces the rate of fluxing of carbon between the >>>>>>>> atmosphere and plants but overall it helps to build the carbon stocks >>>>>>>> in >>>>>>>> biomass and soils and hence reduce the atmospheric CO2. >>>>>>>> >>>>>>>> Another good example for stocks and fluxes behaving very >>>>>>>> differently is the change in precipitation (flux) and atmospheric water >>>>>>>> vapor (stock) under global warming. It is well established now that >>>>>>>> precipitation increases at the rate of 2-3% per deg warming while water >>>>>>>> vapor increases at the rate of about 7% per deg warming. >>>>>>>> >>>>>>>> Best, >>>>>>>> Bala >>>>>>>> >>>>>>>> On Wed, Apr 29, 2020 at 10:18 AM Andrew Lockley < >>>>>>>> andrew.lock...@gmail.com> wrote: >>>>>>>> >>>>>>>>> Poster's note: this has the opposite sign to other work on the >>>>>>>>> subject eg >>>>>>>>> https://keith.seas.harvard.edu/publications/solar-geoengineering-reduces-atmospheric-carbon-burden >>>>>>>>> >>>>>>>>> >>>>>>>>> https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031883 >>>>>>>>> >>>>>>>>> Journal of Geophysical Research: AtmospheresVolume 125, Issue 9 >>>>>>>>> Research Article >>>>>>>>> A Model‐Based Investigation of Terrestrial Plant Carbon Uptake >>>>>>>>> Response to Four Radiation Modification Approaches >>>>>>>>> Lei Duan Long Cao Govindasamy Bala Ken Caldeira >>>>>>>>> First published:04 April 2020 >>>>>>>>> https://doi.org/10.1029/2019JD031883 >>>>>>>>> >>>>>>>>> Abstract >>>>>>>>> A number of radiation modification approaches have been proposed >>>>>>>>> to counteract anthropogenic warming by intentionally altering Earth's >>>>>>>>> shortwave or longwave fluxes. While several previous studies have >>>>>>>>> examined >>>>>>>>> the climate effect of different radiation modification approaches, >>>>>>>>> only a >>>>>>>>> few have investigated the carbon cycle response. Our study examines >>>>>>>>> the >>>>>>>>> response of plant carbon uptake to four radiation modification >>>>>>>>> approaches >>>>>>>>> that are used to offset the global mean warming caused by a doubling >>>>>>>>> of >>>>>>>>> atmospheric CO2. Using the National Center for Atmospheric Research >>>>>>>>> Community Earth System Model, we performed simulations that represent >>>>>>>>> four >>>>>>>>> idealized radiation modification options: solar constant reduction, >>>>>>>>> sulfate >>>>>>>>> aerosol increase (SAI), marine cloud brightening, and cirrus cloud >>>>>>>>> thinning >>>>>>>>> (CCT). Relative to the high CO2 state, all these approaches reduce >>>>>>>>> gross >>>>>>>>> primary production (GPP) and net primary production (NPP). In high >>>>>>>>> latitudes, decrease in GPP is mainly due to the reduced plant growing >>>>>>>>> season length, and in low latitudes, decrease in GPP is mainly caused >>>>>>>>> by >>>>>>>>> the enhanced nitrogen limitation due to surface cooling. The >>>>>>>>> simulated GPP >>>>>>>>> for sunlit leaves decreases for all approaches. Decrease in sunlit >>>>>>>>> GPP is >>>>>>>>> the largest for SAI which substantially decreases direct sunlight, >>>>>>>>> and the >>>>>>>>> smallest for CCT, which increases direct sunlight that reaches the >>>>>>>>> land >>>>>>>>> surface. GPP for shaded leaves increases in SAI associated with a >>>>>>>>> substantial increase in surface diffuse sunlight, and decreases in all >>>>>>>>> other cases. The combined effects of CO2 increase and radiation >>>>>>>>> modification result in increases in primary production, indicating the >>>>>>>>> dominant role of the CO2 fertilization effect on plant carbon uptake. >>>>>>>>> >>>>>>>>> Plain Language Summary >>>>>>>>> A number of radiation modification approaches have been proposed >>>>>>>>> to intentionally alter Earth's radiation balance to counteract >>>>>>>>> anthropogenic warming. However, only a few studies have analyzed the >>>>>>>>> potential impact of these approaches on the terrestrial plant carbon >>>>>>>>> cycle. >>>>>>>>> Here, we simulate four idealized radiation modification approaches, >>>>>>>>> which >>>>>>>>> include direct reduction of incoming solar radiation, increase in >>>>>>>>> stratospheric sulfate aerosols concentration, enhancement of marine >>>>>>>>> low >>>>>>>>> cloud albedo, and decrease in high‐level cirrus cloud cover, and >>>>>>>>> analyze >>>>>>>>> changes in plant photosynthesis and respiration. The first three >>>>>>>>> approaches >>>>>>>>> cool the earth by reducing incoming solar radiation, and the last >>>>>>>>> approach >>>>>>>>> allows more outgoing thermal radiation. These approaches are designed >>>>>>>>> to >>>>>>>>> offset the global mean warming caused by doubled atmospheric CO2. >>>>>>>>> Compared >>>>>>>>> to the high CO2 world, all approaches will limit plant growth due to >>>>>>>>> induced surface cooling in high latitudes and will lead to reduced >>>>>>>>> nitrogen >>>>>>>>> supply in low latitudes, leading to an overall reduction in the plant >>>>>>>>> carbon uptake over land. Different approaches also produce different >>>>>>>>> changes in surface direct and diffuse sunlight, which has important >>>>>>>>> implications for plant photosynthesis. Relative to the unperturbed >>>>>>>>> climate, >>>>>>>>> the combined effects of enhanced CO2 and radiation modifications >>>>>>>>> leads to >>>>>>>>> an increase in plants' primary production. >>>>>>>>> >>>>>>>>> -- >>>>>>>>> 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 view this discussion on the web visit >>>>>>>>> https://groups.google.com/d/msgid/geoengineering/CAJ3C-04U16sw-Z9QCLEVXqs5Z0r0MRzGN0dfr-A8%2By_eaaYiag%40mail.gmail.com >>>>>>>>> <https://groups.google.com/d/msgid/geoengineering/CAJ3C-04U16sw-Z9QCLEVXqs5Z0r0MRzGN0dfr-A8%2By_eaaYiag%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>>> . >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> With Best Wishes, >>>>>>>> >>>>>>>> ------------------------------------------------------------------- >>>>>>>> G. Bala >>>>>>>> Professor >>>>>>>> Center for Atmospheric and Oceanic Sciences >>>>>>>> Indian Institute of Science >>>>>>>> Bangalore - 560 012 >>>>>>>> India >>>>>>>> >>>>>>>> Tel: +91 80 2293 3428; +91 80 2293 2505 >>>>>>>> Fax: +91 80 2360 0865; +91 80 2293 3425 >>>>>>>> Email: gb...@iisc.ac.in; bala....@gmail.com >>>>>>>> Web:http://dccc.iisc.ac.in/dr_govindasamy_bala_profile.html >>>>>>>> ------------------------------------------------------------------- >>>>>>>> >>>>>>>> >>>>>> >>>>>> -- >>>>>> With Best Wishes, >>>>>> >>>>>> ------------------------------------------------------------------- >>>>>> G. Bala >>>>>> Professor >>>>>> Center for Atmospheric and Oceanic Sciences >>>>>> Indian Institute of Science >>>>>> Bangalore - 560 012 >>>>>> India >>>>>> >>>>>> Tel: +91 80 2293 3428; +91 80 2293 2505 >>>>>> Fax: +91 80 2360 0865; +91 80 2293 3425 >>>>>> Email: gb...@iisc.ac.in; bala....@gmail.com >>>>>> Web:http://dccc.iisc.ac.in/dr_govindasamy_bala_profile.html >>>>>> ------------------------------------------------------------------- >>>>>> >>>>>> >>>> >>>> -- >>>> With Best Wishes, >>>> >>>> ------------------------------------------------------------------- >>>> G. Bala >>>> Professor >>>> Center for Atmospheric and Oceanic Sciences >>>> Indian Institute of Science >>>> Bangalore - 560 012 >>>> India >>>> >>>> Tel: +91 80 2293 3428; +91 80 2293 2505 >>>> Fax: +91 80 2360 0865; +91 80 2293 3425 >>>> Email: gb...@iisc.ac.in; bala....@gmail.com >>>> Web:http://dccc.iisc.ac.in/dr_govindasamy_bala_profile.html >>>> ------------------------------------------------------------------- >>>> >>>> >> >> -- >> With Best Wishes, >> >> ------------------------------------------------------------------- >> G. Bala >> Professor >> Center for Atmospheric and Oceanic Sciences >> Indian Institute of Science >> Bangalore - 560 012 >> India >> >> Tel: +91 80 2293 3428; +91 80 2293 2505 >> Fax: +91 80 2360 0865; +91 80 2293 3425 >> Email: gb...@iisc.ac.in; bala....@gmail.com >> Web:http://dccc.iisc.ac.in/dr_govindasamy_bala_profile.html >> ------------------------------------------------------------------- >> >> -- With Best Wishes, ------------------------------------------------------------------- G. Bala Professor Center for Atmospheric and Oceanic Sciences Indian Institute of Science Bangalore - 560 012 India Tel: +91 80 2293 3428; +91 80 2293 2505 Fax: +91 80 2360 0865; +91 80 2293 3425 Email: gb...@iisc.ac.in; bala....@gmail.com Web:http://dccc.iisc.ac.in/dr_govindasamy_bala_profile.html ------------------------------------------------------------------- -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CAD7fhV%3D1qE%2B6AypzzEPdm8MxKzvmM-DAfY_5ayzDdTk06iSZzA%40mail.gmail.com.
