http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=table&application=fm08&convert=&converthl=&refinequery=&formintern=&formextern=&transquery=geoengineering&_lines=&multiple=0&descriptor=%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c326%7c3149%7cSulphate%20Geoengineering%20in%20the%20UT%2fLS:%20Some%20Relevant%20Processes%7cHTML%7clocalhost:0%7c%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c54456110%2054459259%20%2fdata2%2fepubs%2fwais%2fdata%2ffm08%2ffm08.txt
U41E-03 INVITED TI: Sulphate Geoengineering in the UT/LS: Some Relevant Processes AU: * Tuck, A F EM: [EMAIL PROTECTED] AF: Visiting Professor, Physics Department, Imperial College London, Exhibition Road, London, SW7 2AZ, United Kingdom AU: Donaldson, D J AF: Department of Chemistry, University of Toronto, 80 St George Street, Toronto, ON M5S 1A1, Canada AU: Hitchman, M H AF: Atmospheric and Oceanic Sciences, 1225 West Dayton Street, Madison, WI 53706, United States AU: Richard, E C AF: Laboratory for Atmospheres and Space Physics, University of Colorado, Innovation Drive, Boulder, CO 80309, United States AU: Tervahattu, H AF: Nordic Envicon Oy, Koetilantie 3, Helsinki, FIN-00790, Finland AU: Vaida, V AF: Department of Chemistry and Biochemistry, University of Colorado, Campus Box 0215, Boulder, CO 80309, United States AU: Wilson, J C AF: Department of Engineering, University of Denver, DU Campus, Denver, CO 80208, United States AB: We consider the potential effects of meteorological dynamics, the physics and chemistry of aerosols and the photodissociation of sulphuric acid upon the posited maintenance of a 'parasol' of geoengineered sulphate aerosol in the lower stratosphere. Specific observational and experimental results include the spread of tungsten-185 from the Hardtack series of nuclear weapon tests in 1958, satellite observations of the spread of volcanic eruptions, tracer and water profiles in the tropical UT/LS, the organic coating of surfactants on aerosols, the observed distributions of aerosols and the overtone driven photodissociation of sulphuric acid in the stratosphere. A few implications for the logistics of any possible future geoengineering injection are considered briefly. The uncertainties arising from the analysis subtract significantly from the predictability of any supposed amelioration of the effects of global warming from continued increases in carbon dioxide from fossil fuel combustion. DE: 1630 Impacts of global change (1225) DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513) DE: 6309 Decision making under uncertainty SC: Union [U] MN: 2008 Fall Meeting [Comments. We discussed this paper last summer. Comments are found in the archives. AG] http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=table&application=fm08&convert=&converthl=&refinequery=&formintern=&formextern=&transquery=geoengineering&_lines=&multiple=0&descriptor=%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c326%7c2855%7cThe%20Practicality%20of%20Geoengineering%7cHTML%7clocalhost:0%7c%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c54471445%2054474300%20%2fdata2%2fepubs%2fwais%2fdata%2ffm08%2ffm08.txt U41E-07 TI: The Practicality of Geoengineering AU: * Robock, A EM: [EMAIL PROTECTED] AF: Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901, United States AU: Marquardt, A EM: [EMAIL PROTECTED] AF: Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901, United States AU: Kravitz, B P EM: [EMAIL PROTECTED] AF: Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901, United States AU: Stenchikov, G L EM: [EMAIL PROTECTED] AF: Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901, United States AB: Injecting sulfate aerosol precursors into the stratosphere to produce an artificial sulfate aerosol cloud has been suggested as a technique to geoengineer the climate to reduce global warming. Advocates have suggested that this would be easy and inexpensive, but to date there has been no detailed estimate of the actual costs or practicality. Here we evaluate several possible means of injecting the equivalent of 3-5 Tg SO2 per year into the lower Arctic or tropical stratosphere. We assess airplanes, balloons, artillery shells, and space elevators from the viewpoint of cost and possible speed of application. No such systems currently exist, and it would take a major manufacturing effort and deployment experiments to develop any of the proposed mechanisms. We estimate the costs of building the systems and of annual operation and maintenance, and evaluate the environmental impacts at the location of deployment and globally. DE: 1600 GLOBAL CHANGE DE: 1694 Instruments and techniques DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513) DE: 3362 Stratosphere/troposphere interactions DE: 3394 Instruments and techniques SC: Union [U] MN: 2008 Fall Meeting [Comments. Just another upbeat offering from the Red Team. Space elevators? How about space aliens? I am interested in the estimates for airplanes and balloons. A recent Military Channel (yes, there is really a Military Channel) program on the history of the F-15 discussed the Valkyrie, a supersonic high altitude long range bomber capable of sustained flight at 70,000 ft and a ceiling of nearly 80,000. http://en.wikipedia.org/wiki/XB-70_Valkyrie The payloads for the Valkyrie were estimated to be in the range of 25,000-50,000 lbs, although the only planes built were for research purposes before the project was canceled due the development of surface to air missiles that rendered it vulnerable. Work on the prototypes was used in developing the SST and the Concorde. The comment that "No such systems currently exist, and it would take a major manufacturing effort and deployment experiments to develop any of the proposed mechanisms." is a typical Red Team response, equating space elevators with airplanes and balloons in order to dismiss their possible efficacy. I agree that it would take a considerable effort to convert F-15s to delivery platforms for aerosol precursors, but it wouldn't be impossible. Did you also know that there are no CCS systems currently in operation at power plants and it would take a major manufacturing effort and deployment experiments to develop them on a meaningful scale? Same for redoing the electrical grid to accmdate wind turbines and solar concentrators. I also think that artillery shells are out. AG] http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=table&application=fm08&convert=&converthl=&refinequery=&formintern=&formextern=&transquery=geoengineering&_lines=&multiple=0&descriptor=%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c247%7c3477%7cStratospheric%20Aerosol%20Injection%20for%20Geoengineering%20Purposes%7cHTML%7clocalhost:0%7c%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c54463175%2054466652%20%2fdata2%2fepubs%2fwais%2fdata%2ffm08%2ffm08.txt U41E-05 TI: Stratospheric Aerosol Injection for Geoengineering Purposes AU: * Turco, R P EM: [EMAIL PROTECTED] AF: University of California, Los Angeles, Atmospheric and Oceanic Sciences 405 Hilgard Avenue, Los Angeles, CA 90095-1565, United States AU: Yu, F EM: [EMAIL PROTECTED] AF: State University of New York, Albany, Atmospheric Sciences Research Center 251 Fuller Road, Albany, NY 12203, United States AB: A number of studies have focused on the large-scale aspects of massive stratospheric aerosol injections for the purpose of modifying global climate to counterbalance current and future greenhouse warming effects. However, no descriptions of actual injection schemes have been presented at any level of detail; it is generally assumed that the procedure would be straightforward. Approaches mentioned include direct injection of dispersed microparticles of sulfates or other mineral particles, or the emission of precursor vapors, such as sulfur dioxide or hydrogen sulfide, that lead to particle formation. Using earlier aircraft plume research as a guide, we investigate the fate of injected aerosols/precursors from a stratospheric platform in terms of the chemical and microphysical evolution occurring in a mixing plume. We utilize an advanced microphysics model that treats nucleation, coagulation, condensation and other processes relevant to the injection of particulates at high altitudes, as well as the influence of plume dilution. The requirements of particle size and concentration for producing the desired engineered radiative forcing place significant constraints on the injection system. Here, we focus on the effects of early microphysical processing on the formation of a suitable aerosol layer, and consider strategies to overcome potential hurdles. Among the problems explicitly addressed are: the propensity for emitted particles to coagulate to sizes that are optically inefficient at solar wavelengths, accelerated scavenging by an enhanced background aerosol layer, the evolution of size dispersion leading to significant infrared effects, and total mass injection rates implied by stratospheric residence times. We also investigate variability in aerosol properties owing to uncertain nucleation rates in evolving plumes. In the context of the microphysical simulations, we discuss infrastructure requirements in terms of the scale of the intervention and, hence, the overall feasibility of such an approach to climate change mitigation. DE: 0305 Aerosols and particles (0345, 4801, 4906) DE: 0340 Middle atmosphere: composition and chemistry DE: 1605 Abrupt/rapid climate change (4901, 8408) DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513) SC: Union [U] MN: 2008 Fall Meeting [Comments. This is either the same work reported in the Royal Society paper or a follow on. I am guessing that the conclusion is the same as in that paper, that an order of magnitude more precursor is required than based on a 100% conversion to the optimal sized droplets (particles are solids, these aerosols are made up of two liquids--water and sulfuric acid--researchers need to keep the dust and the liquid straight if for no other reason so as not to confuse the already confused media.) Without doing actual field tests, the true composition of the aerosol produced is unknown. However, because some modeling suggests that the process won't be effective is not reason enough to preclude doing any field studies or further modeling. I get the feeling that some of the work being done in this area is not just being done to elucidate the mechanisms and processes that occur, but to attempt to damp down any enthusiasm for funding of research beyond that done by the handful of modelers now at work. After all, isn't the goal of the Red Team to defeat the Blue Team? AG] --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
