By the way, as a follow up to that, has anyone proposed using this very same material as the source of an Arctic geoengineering idea - that is, has anyone proposed something like "cirrus stripping" but for polar stratospheric clouds instead, as a way of helping to cool the Arctic? Might there be a feasible way of doing this?
Cheers, Nathan On Wed, Feb 4, 2015 at 8:25 PM, nathan currier <[email protected]> wrote: > Hi, Michael & Adrian - > > Thanks so much for all of this, which I personally think is very important > material. I found the Sloan-Pollard paper fascinating, in spite of, and > maybe partly also because of, the fact that it isn't a new paper, yet seems > to inject a fresh and tantalizingly relevant paleoclimate perspective into > this discussion of the role of Arctic stratospheric clouds in Arctic > climate - and thus by inference how Arctic stratospheric sulfur injection > could get entangled in all of that in a pretty nasty way. > > Some months ago now, when Ken was asking about "bad memes of > geoengineering", and I mentioned what I saw as the "Pinatubo meme" and the > vague thoughts I had been having about stratospheric H2O, its role in > warming, and various potential interconnections with both methane and > sulfur, and thus more "hidden" positive forcings from it that went along > with the often discussed and more obvious negative ones, I didn't imagine > that what I was thinking of as the worst possible kinds of direct > connections would be so likely as it seems from what you have just sent. > > Right off the bat, one thing it suggests to me is that Arctic-only sulfur > SRM in the stratosphere, which I too had thought was a good idea when I > first had heard of it, might turn out to have been one of the worst > geoengineering ideas proposed, potentially causing more harm than good. Add > to that that Adrian had written then about how the lofting will work quite > poorly in the Arctic, as discussed in his paper. > > To be fair, it is still the net effect that matters, and when I first > wrote about this to the group, I did my own little entirely unprofessional > back-of-the- envelope calculation, in terms of global sulfur SRM issues and > Pinatubo, using the Solomon et al paper on the contribution of > stratospheric H2O to warming in the 90s, and hypothesized, based on some > other papers describing how volcanic injection of H2O can play out in the > stratosphere for ~5-10 years, a "what if" in which a large % of that 90s > H2O perturbation had come directly from Pinatubo itself, how bad would that > be for its overall forcing profile, and yet I found that even then (not so > likely) it would it reduce the cooling efficacy by something like 50% I > think it was, at most....and the amount of that positive forcing tied > directly to the sulfur would be far smaller, too, since H2O is directly > injected in the process............. > > But in the Arctic-only stratospheric sulfur SRM case, on the other hand, > it sounds as though there might be the potential for the whole idea to > actually be close to being outright pernicious and entirely > useless!.....very interesting......thanks again..... > > Cheers, > > Nathan > > On Wed, Feb 4, 2015 at 5:52 PM, Michael Hayes <[email protected]> > wrote: > >> Oliver and List, >> >> The primary cloud condensate nuclei for type one polar stratospheric >> clouds is sulfuric acid. This is a well known and established fact found in >> atmospheric physics. >> >> Here I offer a few reference among the many available: >> >> 1) Theoretical and Modeling Studies of the Atmospheric Chemistry of >> Sulfur: Hazem S. El-Zanan >> >> The relevance of the above book, to this topic, is found within the >> introduction. >> >> 2) A 2D microphysical model of the polar stratospheric CN layer >> <http://onlinelibrary.wiley.com/doi/10.1029/1999GL900187/abstract> >> >> >> 1. Michael J. Mills1, >> 2. Owen B. Toon1and >> 3. Susan Solomon2 >> >> *"Each spring a layer of small particles forms between 20 and 30 km >> altitude in the polar regions. We present the first self-consistent >> explanation of the observed “CN layer” from a 2D microphysical model of >> sulfate aerosol. Our theory relies on photolysis of H2SO4 and SO3, >> consistent with recent laboratory measurements, to produce SO2 in the upper >> stratosphere and mesosphere. An additional source of SO2may be required. >> Nucleation throughout the polar winter extends the top of the aerosol layer >> to higher altitudes, despite strong downward transport of ambient air. This >> may affect heterogeneous chemistry at the top of the aerosol layer in polar >> winter and spring.".* >> >> Please pay close attention to the '*Particle Microphysics*' section and >> the conclusion in the above paper. >> >> Further, if we take a close look at the '*Pinatubo Effect*', in >> relationship to ozone production with elevated SO2 levels, we find a >> significant downward trend in the "*global mean column ozone*". This >> scenario is explained in the following paper. Please see pg. 403, 2nd >> column, 4th-5th para.: >> >> 3) Atmospheric effects of the Mt. Pinatubo eruption >> <http://www.nuclear.lu.se/fileadmin/nuclear/Undervisning/Atmosfaerskurs/P04.pdf> >> : MP McCormick, LW Thomason, CR Trepte - Nature, 1995 >> >> However, we can find reference to the apparent contradictions found in >> the premise that SAI offers no threat to polar stability while lowering the >> 'global average temperature' in a far more topical references...such as: >> >> 4) Polar stratospheric cloud >> <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#Types> (Wiki) >> PSCs are classified into three types Ia, Ib and II according to their >> chemical >> composition <http://en.wikipedia.org/wiki/Chemical_composition> which >> can be measured using LIDAR <http://en.wikipedia.org/wiki/LIDAR>. The >> technique also determines the height and ambient temperature of the >> cloud.[4] >> <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-wegener-4> >> >> - Type I clouds contain water, nitric acid >> <http://en.wikipedia.org/wiki/Nitric_acid> and/or sulfuric acid >> <http://en.wikipedia.org/wiki/Sulfuric_acid> and they are a source of >> polar ozone depletion <http://en.wikipedia.org/wiki/Ozone_depletion>. >> [5] >> <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-5> >> - Type Ia clouds consist of large, aspherical particles, >> consisting of nitric acid trihydrate (NAT).[4] >> >> <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-wegener-4> >> - Type Ib clouds contain small, spherical particles >> (non-depolarising), of a liquid supercooled >> <http://en.wikipedia.org/wiki/Supercooled> ternary solution (STS) >> of sulfuric acid, nitric acid and water.[4] >> >> <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-wegener-4> >> - Type Ic clouds consist of metastable >> <http://en.wikipedia.org/wiki/Metastability> water-rich nitric >> acid in a solid phase.[6] >> <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-6> >> - Type II clouds, which are very rarely observed in the Arctic, >> consist of water ice <http://en.wikipedia.org/wiki/Ice> only.[4] >> >> <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-wegener-4> >> >> (My highlights) >> >> 5) Also, the Harvard website "Equable Climate Dynamics-Polar >> Stratospheric Clouds >> <http://www.seas.harvard.edu/climate/eli/research/equable/psc.html>*" *offers >> a well written oversight of PSC trapping polar heat and >> the reference section has a number of citations worth reading. >> >> 6) And again, we should pay close attention to the paper >> I originally sited for a view of the PSC dynamics within an ancient >> "greenhouse" world. Please pay close attention to the 'Discussion' section. >> Polar Stratospheric Clouds: A high latitude warning mechanism in an >> ancient greenhouse world: Sloan and Pollard >> <ftp://ftp.tudelft.nl/pub/TUDelft/irctr-rse/Mieke/Papers/SloanPollard98-PSCforHighLatPTMwarmArctic.pdf> >> >> >> In brief summation, an *intentional* increase in stratospheric sulfuric >> acid, per SAI, *will* trigger a corresponding increase in the most >> common PSC type of formation (type 1) and thus this action would represent >> an *intentional* increase in polar temperatures. Thus, such *intentional* >> actions would *constitute a knowable action** resulting in the >> intentional acceleration of polar methane hydrate releases* and the >> existential threat that such releases pose (i.e. Arctic Methane Tipping >> Point <https://robertscribbler.wordpress.com/tag/esas/>). Thus, the >> *intentional* injection of sulfuric acid into the atmosphere represents >> an real and significant threat to climate stability, as we know it, and >> will further accelerate the current trend towards an equitable (unstable) >> climate....*intentionally*. >> Oliver, thank you for your question and I hope my response offers a >> reasonable degree of information for you to decide for yourself if SAI is >> or is not a threat to polar (and global) climate stability as opposed to >> the current hyperbolicly positive rhetoric concerning the efficaciousness >> of the SAI concept. >> >> Best regards, >> >> Michael >> >> >> On Wednesday, February 4, 2015 at 7:53:31 AM UTC-8, olivermorton wrote: >> >>> What's the proposed SAI mechanism enhancing PSC? >>> >>> On 4 February 2015 at 01:48, Michael Hayes <[email protected]> wrote: >>> >>>> Hi Folks, >>>> >>>> This level of discussion on SAI seems to be premature. We have yet to >>>> see any...any...models concerning the highly predictable increase in Polar >>>> Stratospheric Cloud (PSC) production which will be caused by SAI. This is >>>> not a trivial precondition to further discussion. As, the triggering of an >>>> Arctic Methane Tipping Point, through increasing PSC production, would make >>>> SAI simply a dysfunctional option. >>>> >>>> Please read the following paper concerning the vital need >>>> to....not...increase PSCs through SAI. >>>> >>>> Polar Stratospheric Clouds: A high latitude warning mechanism in an >>>> ancient greenhouse world. >>>> <ftp://ftp.tudelft.nl/pub/TUDelft/irctr-rse/Mieke/Papers/SloanPollard98-PSCforHighLatPTMwarmArctic.pdf> >>>> >>>> >>>> Best, >>>> >>>> Michael >>>> >>>> On Friday, January 30, 2015 at 12:54:21 AM UTC-8, Andy Parker wrote: >>>>> >>>>> Hey folks, the Washington Post just published an op ed on the messy >>>>> politics of solar geoengineering, written by David Keith and me: >>>>> http://www.washingtonpost.com/opinions/whats-the-right-tempe >>>>> rature-for-the-earth/2015/01/29/b2dda53a-7c05-11e4-84d4- >>>>> 7c896b90abdc_story.html >>>>> >>>> -- >>>> You received this message because you are subscribed to a topic in the >>>> Google Groups "geoengineering" group. >>>> To unsubscribe from this topic, visit https://groups.google.com/d/ >>>> topic/geoengineering/LJWQD4s2w_U/unsubscribe. >>>> To unsubscribe from this group and all its topics, send an email to >>>> [email protected]. >>>> To post to this group, send email to [email protected]. >>>> Visit this group at http://groups.google.com/group/geoengineering. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> >>> >>> -- >>> O=C=O >>> >>> Oliver Morton >>> Briefings Editor >>> The Economist >>> >>> +44 20 7830 7041 >>> >>> O=C=O >>> >>> *This e-mail may contain confidential material. 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