Helpful comments from Hugh to put this paper in context.  However there is one observation in the paper that struck me as remarkably powerful in support of the case for tethered balloons.  This is the only method for lofting the aerosol precursors that required the lifting of only those materials to the stratosphere.  That would, at least superficially, suggest a vastly less energy and materials intensive engineering solution than one that requires thousands of sorties of heavy aircraft to fly up there just to drop off relatively small payloads on each occasion.

Regards

Robert


On 05/11/2023 22:34, Hugh Hunt wrote:
Robert et al,
That paper from 2012 was written in the context of the day - the idea of using aircraft for delivery was de-facto the only and the obvious solution.  But it had not been properly evaluated. or costed  It's probably fair to say that we were rocking the boat a bit, and the tethered balloon idea came out on top.  Who knows, it may still be a good solution.  But along the way we did our best to evaluate the various alternatives such as airships and superguns.  The only one that's a non starter is tall towers.  We put in on there because there was a paper published at the time that was promoting a tower on the top of Everest.  I cannot imagine any world in which tall towers for the delivery of aerosols would work.

I think you're right, it would be good to re-evaluate all these options.

Hugh
------------------------------------------------------------------------
*From:* healthy-planet-action-coalit...@googlegroups.com <healthy-planet-action-coalit...@googlegroups.com> on behalf of robertgch...@gmail.com <robertgch...@gmail.com>
*Sent:* Sunday, November 5, 2023 10:23 PM
*To:* Douglas MacMartin <dgm...@cornell.edu>; robert.ch...@open.ac.uk <robert.ch...@open.ac.uk>; Andrew Lockley <andrew.lock...@gmail.com>; Gilles de Brouwer <gdebrou...@gmail.com> *Cc:* healthy-planet-action-coalition <healthy-planet-action-coalit...@googlegroups.com>; Planetary Restoration <planetary-restorat...@googlegroups.com>; geoengineering <geoengineering@googlegroups.com> *Subject:* Re: [prag] RE: [geo] Re: Hansen Vs. Mann - Is Global Warming Linear Or Exponential? - CleanTechnica

Doug

Do you think any of the work covered by Davidson et al in the paper, a link <http://www2.eng.cam.ac.uk/~hemh1/SPICE/papers/PhilTransRoySoc_LiftingOptions_Davidson_Burgoyne_Hunt_Causier.pdf>to which was earlier circulated by Hugh Hunt (co-author)?  They seemed to conclude that the engineering realities strongly favoured tethered balloons.

Regards

Robert


On 05/11/2023 19:01, Douglas MacMartin wrote:

Broadly speaking I don’t think the direct delivery cost of material to the stratosphere is a significant factor influencing any decision to deploy.  (Vs, for example, the expected geopolitical ramifications of a choice, the projected impacts, or the costs associated with any fund to compensate those who believe that they will be harmed by deployment).  Aircraft have consistently wound up as the cheapest approach to deliver material based on today’s technology, though of course that could change.

Also relevant in thinking about alternate delivery mechanisms though is that aircraft engines are currently manufactured by only a few companies all in a handful of countries, and none of these manufacturers would sell any engine to anyone without at least tacit approval by the country they are in… that greatly limits the number of countries that are capable of deploying, so alternative engines or delivery modes may be more important in thinking about governance challenges associated with who is actually capable of initiating a deployment that has the potential to be scaled and sustained.

*From:*geoengineering@googlegroups.com <mailto:geoengineering@googlegroups.com> <geoengineering@googlegroups.com> <mailto:geoengineering@googlegroups.com> *On Behalf Of *robertgch...@gmail.com <mailto:robertgch...@gmail.com>
*Sent:* Sunday, November 5, 2023 1:56 PM
*To:* Andrew Lockley <andrew.lock...@gmail.com> <mailto:andrew.lock...@gmail.com>; Gilles de Brouwer <gdebrou...@gmail.com> <mailto:gdebrou...@gmail.com> *Cc:* healthy-planet-action-coalition <healthy-planet-action-coalit...@googlegroups.com> <mailto:healthy-planet-action-coalit...@googlegroups.com>; Planetary Restoration <planetary-restorat...@googlegroups.com> <mailto:planetary-restorat...@googlegroups.com>; geoengineering <geoengineering@googlegroups.com> <mailto:geoengineering@googlegroups.com> *Subject:* Re: [geo] Re: Hansen Vs. Mann - Is Global Warming Linear Or Exponential? - CleanTechnica

Can someone do the following calculations?  How many shells?  How much material would they consume each year?  What happens to the shell casings once they've delivered their load?  What environmental impact would these discarded shell casings have and in particular would they contain any environmentally undesirable materials?  What would be necessary for this to receive social licence?

Regards

Robert

On 05/11/2023 18:22, Andrew Lockley wrote:

    I've already looked at this. The meteor missile (modern) and
    blood hound (cold war) use ram rockets. Nammo make ram artillery,
    and there's Chinese manufacturers, too. It's not inexpensive to
    start these ramjets, considering rockets or barrel wear. Coil
    guns might be viable. There's manufacturers eg velontra.com
    <http://velontra.com/> making small hypersonic jets, which don't
    require a hard start.

    Ballistic flight makes recovery difficult.

    On Sun, 5 Nov 2023, 18:15 Gilles de Brouwer,
    <gdebrou...@gmail.com <mailto:gdebrou...@gmail.com>> wrote:

        A low cost SAI option?

        Regarding the trillions or billions to do SAI geoengineering,
        consider this option:

        Watch "How ramjets may change the role of artillery on the
        battlefield" on YouTube

        https://youtu.be/0vIPNElDkns?si=9Z_mUQUXBm-4dBxF
        <https://youtu.be/0vIPNElDkns?si=9Z_mUQUXBm-4dBxF>

        At 4:21 you can see the 150km range parabolic trajectory goes
        as high as 105km altitude!

        Maybe Iowa battleship 16 inch guns with this ramjet tech
        could send stuff to orbit.

        Or could this be a low cost SAI geoengineering option?

        1. How much would it cost to refurbish and send these old
        battleships to the Arctic and Antarctic waters and deliver to
        much higher altitudes?  The armor plating would make the
        battleships iceberg damage resistant.

        2. How much longer would the particles stay at useful altitudes?

        3. Would they stay in place much longer with little wind at
        these very high altitudes?

        4. Would it be more effective than aircraft delivered SAI?

        Note from the Iowa Class Wikipedia page: "...all four are
        museum ships part of non-profit maritime museums across the US."

        Gilles

        On Sat, Nov 4, 2023, 5:16 PM Jim Baird
        <jim.ba...@gwmitigation.com
        <mailto:jim.ba...@gwmitigation.com>> wrote:

            From the Physics and Economics of Thermodynamics
            Geoengineering, reference 77 of  the Healthy Climate
            Action Coalition Petition to World Leaders: The Case for
            Urgent Direct Climate Cooling, The cost of removing 1139
            Gt of CO2  with this technology (Negative Emissions CO2
            OTEC) would therefore be $175 trillion. CDR technology
            for creating synthetic fuel from atmospheric CO2 or for
            other purposes currently costs about $600 per ton, with a
            goal of reducing this to below $100. [48] So, a goal of
            returning atmospheric CO2 levels to preindustrial  from a
            2054 level of 1577 Gt is likely to cost at a minimum $114
            trillion.

            *From:* healthy-planet-action-coalit...@googlegroups.com
            <mailto:healthy-planet-action-coalit...@googlegroups.com>
            *On Behalf Of *Gilles de Brouwer
            *Sent:* November 4, 2023 4:21 PM
            *To:* H simmens <hsimm...@gmail.com
            <mailto:hsimm...@gmail.com>>
            *Cc:* healthy-planet-action-coalition
            <healthy-planet-action-coalit...@googlegroups.com
            <mailto:healthy-planet-action-coalit...@googlegroups.com>>;
            via NOAC Meetings <noac-meeti...@googlegroups.com
            <mailto:noac-meeti...@googlegroups.com>>; Planetary
            Restoration <planetary-restorat...@googlegroups.com
            <mailto:planetary-restorat...@googlegroups.com>>;
            geoengineering <geoengineering@googlegroups.com
            <mailto:geoengineering@googlegroups.com>>
            *Subject:* Re: Hansen Vs. Mann - Is Global Warming Linear
            Or Exponential? - CleanTechnica

            My comment left on the article:

            Steve I like your writing, but "Trillions" is obviously
            wrong.  Billions is more realistic even with expensive
            new high altitude aircraft, but maybe much less expensive
            with a small fleet of specialty airships.

            All the SAI geoengineering risks are scare mongering
            without data to back it up and such dogma unscientific
            opinions from "scientists" are damaging to science as an
            institution.  AI, for example genetic algorithms or
            better could design an SAI strategy that minimizes the
            negatives, as it's an optimization problem with infinite
            variables which is why progress is so slow.  Coupling
            computational models with small scale real atmosphere
            experiments with full public data access for review is
            critical to make a smart decision to potentially avoid
            billions starving, cooking, and/or dying of thirst, or
            migrating.

            Thanks,
            Gilles de Brouwer

            On Sat, Nov 4, 2023 at 3:10 PM H simmens
            <hsimm...@gmail.com <mailto:hsimm...@gmail.com>> wrote:

                

                This article provides the author an opportunity to
                declare war on Geo engineering by for example
                claiming that scientists estimate that Geoengineering
                will cost “on the order of tens of trillions of
                dollars”.

                Nice to know that we can count on the media to be
                fair and balanced.

                Herb


                
https://cleantechnica.com/2023/11/03/hansen-vs-mann-is-global-warming-linear-or-exponential/
                
<https://cleantechnica.com/2023/11/03/hansen-vs-mann-is-global-warming-linear-or-exponential/>

                Herb Simmens
                Author of /A Climate Vocabulary of the Future/

                “A SciencePoem and an Inspiration.” Kim Stanley Robinson
                @herbsimmens
                HerbSimmens.com

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