Research could look at that, but the approach I propose would put the SO2 above the boundary layer, which would let it spread more broadly, lead to a longer lifetime, and why limit one¹s coverage so much to shipping lanes? It seems to me that the bunker fuel suggestion is closer to what the cloud brightening approach is attempting.
Mike On 8/5/14 5:06 PM, "Andrew Lockley" <andrew.lock...@gmail.com> wrote: > Better perhaps to adjust bunker fuel sulphur. Jason Blackstock (cc) did some > excellent work on this, which I don't think got published. > > Presently the trend is for desulphurisation of marine bunker fuel, giving > perfectly sensible port air quality improvements. This is, I understand, now > the subject of legislation. > > However, in the deep ocean, these sulphur cuts result in measurable global > warming. Simply replacing the bunker fuel sulphur for open ocean use would > potentially be helpful. > > I hope there's some research on this in the literature, but presently I'm > unaware of any. > > A > > On 5 Aug 2014 20:45, "Alan Robock" <rob...@envsci.rutgers.edu> wrote: >> >> >> Dear Mike, >> >> I don't understand this suggestion. Because of the shorter sulfate lifetime >> than in the stratosphere (even if it is more than the 1 week you get for >> surface injections), you would require a much larger sulfur injection for the >> same radiative forcing as compared to the stratosphere, and a much larger >> resulting acid deposition in remote areas. And how could you be guaranteed >> to maintain the emissions from a lot of stacks from small enterprises that >> would keep changing over time based on business variations and local >> environmental laws? This seems to be a much riskier strategy even than >> stratospheric injections from a centralized operation. >> >> And why would you think most removal would be in the ITCZ? That would >> require the sulfate to enter the ITCZ from the surface in specific tropical >> regions. >> >> Alan >> >> Alan Robock, Distinguished Professor >> Editor, Reviews of Geophysics >> Director, Meteorology Undergraduate Program >> Department of Environmental Sciences Phone: +1-848-932-5751 >> <tel:%2B1-848-932-5751> >> Rutgers University Fax: +1-732-932-8644 >> <tel:%2B1-732-932-8644> >> 14 College Farm Road E-mail: rob...@envsci.rutgers.edu >> New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock >> http://twitter.com/AlanRobock >> Watch my 18 min TEDx talk at http://www.youtube.com/watch?v=qsrEk1oZ-54 >> On 8/5/2014 2:39 PM, Mike MacCracken wrote: >> >> >>> Regarding this proposal for sustaining the sulfate cooling influence, the >>> suggestion on this that I have been making for several years (see refs >>> below, among others) is similar: rather than having a relatively high >>> sulfate loading concentrated over populated areas, inject SO2 above the >>> boundary layer (important to promote a longer lifetime) to create thinner >>> sulfate layers over much larger remote areas of the ocean (e.g., over the >>> Pacific and Indian Oceans), hoping to promote both clear sky and cloudy sky >>> brightness. Doing this over the ocean would take advantage of its low albedo >>> so that the sulfates would not be offsetting reflected solar radiation from >>> the surface. Doing this over larger areas and at lower loadings would tend >>> to moderate the change in energy in a given area, although there would need >>> to be testing of this. Most removal might come in ITCZ rains, mostly over >>> the ocean. >>> >>> Mike MacCracken >>> >>> >>> MacCracken, M. C., 2009: Beyond Mitigation: Potential Options for >>> Counter-Balancing the Climatic and Environmental Consequences of the Rising >>> Concentrations of Greenhouse Gases, Background Paper to the 2010 World >>> Development Report, Policy Research Working Paper (RWP) 4938, The World >>> Bank, Washington, DC, May 2009, 43 pp. >>> >>> MacCracken, M. C., 2009: On the possible use of geoengineering to moderate >>> specific climate change impacts, Environmental Research Letters, 4 >>> (October-December 2009) 045107 doi:10.1088/1748-9326/4/4/045107 >>> [http://www.iop.org/EJ/article/1748-9326/4/4/045107/erl9_4_045107.html]. >>> >>> MacCracken, M. C., 2011: Potential Applications of Climate Engineering >>> Technologies to Moderation of Critical Climate Change Impacts, IPCC Expert >>> Meeting on Geoengineering, 20-22 June 2011, Lima, Peru, pages 55-56 in >>> Meeting Report, edited by O. Edenhofer, R. Pichs-Madruga, Y. Sokona, C. >>> Field, V. Barros, T. F. Stocker, Q. Dahe, J. Minx, K. Mach, G.-K. Plattner, >>> S. Schlömer, G. Hansen, and M. Mastrandrea, Intergovernmental Panel on >>> Climate Change, Geneva, Switzerland. >>> >>> >>> >>> On 8/1/14 8:53 AM, "ecologist" <ecologi...@gmail.com >>> <http://ecologi...@gmail.com> > wrote: >>> >>> >>>> Currently, anthropogenic tropospheric aerosols present both Dr Jekyll and >>>> Mr Hyde faces. >>>> >>>> On the one hand, tropospheric aerosols play an important role on climate, >>>> with a net cooling radiative forcing effect. >>>> On the other hand, tropospheric aerosols affect terrestrial ecosystems and >>>> human health and are associated with increased heart, lung and respiratory >>>> diseases, which lead to disablement and numerous premature human deaths >>>> (Shindell et al, 2012). >>>> >>>> Consequently, reducing anthropogenic tropospheric aerosols emissions, on >>>> the one hand will lead to a positive forcing (warming) at local and >>>> regional scale, and on the other hand will save numerous lives and >>>> significantly reduce health costs. >>>> >>>> What is proposed is to investigate means whereby the cooling effect of >>>> current emissions is kept unchanged and their deleterious effects are >>>> reduced, using only modifications of existing industrial aerosols emitters. >>>> Key advantages of such investigations are that they avoid most of the >>>> roadblocks associated with SRM. >>>> So, what is proposed is a Win-Win research program that will at the same >>>> time allow indirect geoengineering research, and reduce tropospheric >>>> pollution. >>>> (Important remark: it is not proposed to perform CCS, or CDR). >>>> >>>> This is so, because the current anthropogenic tropospheric sulphate >>>> aerosol emissions are estimated to be almost two orders of magnitude larger >>>> than requested by Stratospheric Particle Injection geoengineering schemes >>>> to offset the effects of a 2 X CO2 (carbon dioxide concentration doubling >>>> in the atmosphere). >>>> Thus the strategy to reduce current sulphate tropospheric emissions and at >>>> the same time to keep their current cooling effects will be like performing >>>> indirect climate engineering without the need to artificially inject >>>> sulphates in the stratosphere. >>>> >>>> Now, the radiative forcing due to sulphate aerosols is estimated to be >>>> -0.4 W/m2 with a range of -0.2 to -0.8 W/m2. >>>> On a global average basis, the sum of direct and indirect radiative >>>> forcing at the top of atmosphere by anthropogenic aerosols is estimated to >>>> be -1.2 W/m2 [-2.4 to -0.6 W/m2] (cooling) over the period of 1750 - 2000. >>>> This is significant when compared to the positive (warming) forcing of >>>> +2.63 [±0.26] W/m2 by anthropogenic long-lived greenhouse gases over the >>>> same period [Forster et al., 2007]. >>>> In heavily polluted regions, aerosol cooling overwhelms greenhouse warming >>>> [Ramanathan et al., 2001; Li et al., 2010]. >>>> >>>> The tropospheric aerosol lifetimes are approximately 1 to 2 weeks, which >>>> is quite shorter. Therefore, these current human made aerosols have an >>>> uneven distribution, both horizontally and vertically, and are more >>>> concentrated near their source regions over continents and in the boundary >>>> layer. >>>> Emission reductions of aerosols in the troposphere will lead to a positive >>>> forcing (warming), unless the sulphates lifetimes are increased and their >>>> horizontal and vertical distribution are improved. Whilst the particulates >>>> are removed, some part of the sulphates can be lofted higher to where they >>>> can act as a solar-reflective shield to cool larger regions. >>>> >>>> To do so, what is proposed is to model the effects of a theoretical >>>> fivefold aerosols emission reduction (80% removal of sulphates, NOx, and > >>>> 95% removal of soot, black carbon, ashŠ) by adding filters or electrostatic >>>> precipitators to the flue stack of a majority of fossil fuel fired power >>>> plants, for adequate particulate filtering and scrubbing, and at the same >>>> time increasing the height release of sulphates for a reduced number of >>>> other power plant stacks in order to allow these (20% SOx) emissions to >>>> over pass the boundary layer and stay longer in the atmosphere. >>>> >>>> This can be performed by the use of taller chimneys allowing the flue >>>> gases to pass the boundary layer, so that the impact of a regional emission >>>> reduction is not confined to the region itself, by allows intercontinental >>>> transport (long-range transport) of these sulphates produced by existing >>>> anthropogenic aerosols. >>>> Several other possibilities exist to increase the height release and >>>> dilution of gas emissions from flue stacks. >>>> >>>> This strategy was proposed in page 818-819 of an open access article >>>> http://www.sciencedirect.com/science/article/pii/S1364032113008460 Fighting >>>> global warming by climate engineering. >>>> >>>> Two figures are attached to summarize this research proposal >>>> >>>> >>>> Public perception of SRM climate engineering is often presented as Ulysses >>>> choices between the perils of Scylla and Charybdis, despite the very good >>>> cooling potential to mitigate global warming, and the high effectiveness >>>> and accessibility of geoengineering schemes consisting of the stratospheric >>>> injection of sulphate aerosols. >>>> The Win-Win strategy proposed here may change this perception at the same >>>> time as helping to advance CE research... >>>> >>>> >>>> Renaud de_Richter, PhD >>>> http://www.solar-tower.org.uk/ >>>> >>> -- >>> 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 http://groups.google.com/group/geoengineering. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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