Geoengineering bombs

[Andrew Lockley]

Much ink has been spilled over how to get sulphur into the stratosphere. In conversation with a prominent scientist today, I was prompted to do a bit more research on possible uses of geoengineering bombs.

I've previously considered using a 2 stage thermobaric bomb for geoengineering. (Subject overview here https://euro-sd.com/2022/11/articles/26805/thermobarics-developments-and-deployments/ .) The first stage would disperse then deflagrate sulphur into the air, forming a hot cloud of SO2. Instantly after, a second charge would disperse graphene into the oxygen-depleted cloud. This would provide convective lift - firstly from the initial thermobaric bomb, then from solar heating on the graphene. This idea has been explored in a paper that was covered by Reviewer 2 https://spotify.link/QGotJhM8HDb - albeit in an alternative, non explosive implementation. 

However, there's been much critical comment on the use of black carbon as either a lifting or shading material, so I didn't pursue this further.

Today, during this twitter discussion, it occurred to me to revisit the idea. What if high altitude or high power geoengineering bombs were used?

The US MOAB is the largest NATO conventional munitions - 10t, roughly equivalent to a WWII grand slam. With a plume height of 10kft - approx 3km https://www.opendemocracy.net/en/article_1617jsp/ , it can add significant vertical range to any sulfur insertion efforts. However, its design isn't readily modifiable, as it uses TNT explosive. However, the BLU-82 daisycutter is a smaller, but still very large conventional bomb. Unlike the MOAB, it uses a slurry of fuel/oxidiser. There's been quite a bit of work on these explosive composites https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201706293

How could such an idea be implemented? The BLU-82 is dropped by a tactical cargo aircraft C-130 class, which has a pretty low service ceiling of 7-10km, depending on payload. 

The KC-135 could theoretical carry 5 BLU-82 in its (37t) payload at 50kft (~15km) - although it's not a bomber, and the crew would presumably have to wear space suits if the bombs were carried internally in a cargo conversion.

By uprating the mass of the BLU-82 (it's basically just a barrel bomb), or detonating several in close proximity - such as on a daisychain - the mushroom cloud could presumably exceed that of the MOAB - perhaps adding around 5km altitude to the detonation height - likely just under 15k.

There are obvious practical issues with this approach, but these may be surmountable 

1) gravity bombs will lose altitude before aircraft septation distance is achieved. Large parachutes add weight, cost and complexity, and work less well at altitude. 

2) glide bomb conversions can maintain altitude better, but may require tow lines to ensure they're adequately separated at point of detonation. I know of no mid-air towed deployment from a cargo plane ramp. Glide bombs are also costly - requiring wings, and possibly active control surfaces.

3) to get an adequate mushroom cloud, multiple bombs should be simultaneously detonated within perhaps r=30m sphere. Getting 3-5 bombs to overlap such a sphere would be achievable with a daisychain - but any more would require coordination between multiple aircraft. Formation flying would further increase the risk to deploying aircraft, from both blast and collision.

An alternative approach would be to do a ground burst. This dispenses with the aircraft entirely, but needs a *very* much larger plume. Accordingly, you'd likely want to load an entire year's supply of Sulphur and liquid Oxygen into a few million 1000l IBC containers and pop the lot in one go. This should allow you to get the mushroom cloud right up into the stratosphere from the ground, provided you start at a reasonable elevation (Atlas, Andes, etc.) https://en.m.wikipedia.org/wiki/Mushroom_cloud#/media/File%3ANukecloud.png data extracted from https://www.jstor.org/stable/443658

Fortunately, 30°N/S is both a sensible latitude for geoengineering and the location of lots of deserts, where you can do this sort of thing without substantial collateral damage. 

In summary, this is probably quite daft, but not so daft that it can be immediately dismissed. 

It would be good to hear from list members on this idea. 

Andrew 

[Adrian Hindes]

This is probably simultaneously not a technically daft idea (worth exploring for the possibility of different deployment options), whilst also being extraordinarily dangerous to actually entertain and consider. In my view, it's entirely possible we see unilateral/minilateral SRM ramp-up, and if these kinds of techniques are openly published about then it becomes a legitimate info-hazard to the security of the Earth System. 

Military-industrial complexes tend not to care too much about side-effects when immediate response options are under consideration (cf. Manhattan Project, and the arms race to the H-bomb from there...). 

Utilizing conventional munitions would put stratospheric aerosols squarely in the securitization domain, heavily increasing the risk of a "climate war"  (see e.g.  https://doi.org/10.1016/j.esr.2022.101031 for current research along similar lines.)

[Andrew Lockley]

I fail to see why geoengineering bombs are inherently militarised. Explosives are used in mining, fireworks, manufacturing and many other applications.

Geoengineering bombs aren't even particularly easy to make, vs methods like balloons or ground level carbonyl sulfide release - both of which are already in the public domain. 

Other than being a bit more impressive/crazy, they're not that different to a lot of the other stuff out there. 

A

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