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.
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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
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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?
Robert
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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?
RegardsRobert
On 05/11/2023 18:22, Andrew Lockley wrote:
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Thanks Hugh. I knew this had been addressed
previously and you saved me the trouble of locating the paper.
Someone might want to spend a little time updating the figures
you developed for artillery shells to take account of any
advances over the last decade. It seems unlikely that this
would make them look any more feasible. Ditto for aircraft.
Robert
Hi Robert,We addressed this in our 2012 paper here, for SPICE
delivery by Aircraft we get as around £100bn, and artillery is around £1trillion - see Fig 8Hugh
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Subject: Re: [geo] Re: Hansen Vs. Mann - Is Global Warming Linear Or Exponential? - CleanTechnica
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Doug
Do you think any of the work covered by
Davidson et al in the paper, a link
to which was earlier circulated by Hugh Hunt (co-author)?
They seemed to conclude that the engineering realities strongly
favoured tethered balloons.
Robert
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.
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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.
Robert
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
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Subject: Re: [prag] RE: [geo] Re: Hansen Vs. Mann - Is Global Warming Linear Or Exponential? - CleanTechnica
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