Herb, at about 14:30 minutes of the Intimate Conversation YouTube Hansen says the annual cost of CDR is now between 3.5 and 7 trillion, and the cost of the decrease of aerosols is $115 to $230 trillion. So I don’t you can put this on the media.
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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.
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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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
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 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, <gdebr...@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
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
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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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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
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
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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
On Nov 6, 2023, at 2:14 AM, Ye Tao <t...@rowland.harvard.edu> wrote:
I agree that balloons would be much superior to planes. This is not only because of energy and material costs, but also the lack of stratospheric NOx and H2O injection from aircraft engine exhausts.
Ye
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On Nov 6, 2023, at 4:17 AM, Hugh Hunt <he...@cam.ac.uk> wrote:
Ben, I don't think anyone has tethered a balloon at 20km. And if ever they do then they have to figure how to pump stuff up the tether. These are the two big challenges. Hugh
From: Ben Ballard <benwb...@gmail.com>
Sent: Monday, November 6, 2023 9:11 AM
To: Ye Tao <t...@rowland.harvard.edu>
Cc: robert...@gmail.com <robert...@gmail.com>; Hugh Hunt <he...@cam.ac.uk>; Douglas MacMartin <dgm...@cornell.edu>; robert...@open.ac.uk <robert...@open.ac.uk>; Andrew Lockley <andrew....@gmail.com>; Gilles de Brouwer <gdebr...@gmail.com>; healthy-planet-action-coalition <healthy-planet-...@googlegroups.com>; Planetary Restoration <planetary-...@googlegroups.com>; geoengineering <geoengi...@googlegroups.com>
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On Nov 6, 2023, at 6:33 AM, Ben Ballard <benwb...@gmail.com> wrote:
I agree that balloons would be much superior to planes. This is not only because of energy and material costs, but also the lack of stratospheric NOx and H2O injection from aircraft engine exhausts.
Ye
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On Nov 6, 2023, at 4:17 AM, Hugh Hunt <he...@cam.ac.uk> wrote:
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far distance beyond and above a mountaineast northeasterlyas I drove from Salt Lake City toward the setting sun
I'd be interested to learn more.
Why not couple balloon with wind energy harvesting? Basically
let the balloon out during high wind and drag them back during
slower wind. Might consider a shape-changing sail in the
tropospheric portion of the tether to modulate drag and change
pulling directions.
Ye
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