Toward practical stratospheric aerosol albedo modification: Solar-powered lofting

[Andrew Lockley]

https://advances.sciencemag.org/content/7/20/eabe3416

Toward practical stratospheric aerosol albedo modification: Solar-powered lofting

View ORCID ProfileRu-Shan Gao1,†, View ORCID ProfileKaren H. Rosenlof1,*,†, View ORCID ProfileBernd Kärcher2, View ORCID ProfileSimone Tilmes3, Owen B. Toon4, View ORCID ProfileChristopher Maloney1,5 and Pengfei Yu6,*

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Science Advances  14 May 2021:

Vol. 7, no. 20, eabe3416

DOI: 10.1126/sciadv.abe3416

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Abstract

Many climate intervention (CI) methods have been proposed to offset greenhouse gas–induced global warming, but the practicalities regarding implementation have not received sufficient attention. Stratospheric aerosol injection (SAI) involves introducing large amounts of CI material well within the stratosphere to enhance the aerosol loading, thereby increasing reflection of solar radiation. We explore a delivery method termed solar-powered lofting (SPL) that uses solar energy to loft CI material injected at lower altitudes accessible by conventional aircraft. Particles that absorb solar radiation are dispersed with the CI material and heat the surrounding air. The heated air rises, carrying the CI material to the stratosphere. Global model simulations show that black carbon aerosol (10 microgram per cubic meter) is sufficient to quickly loft CI material well into the stratosphere. SPL could make SAI viable at present, is also more energy efficient, and disperses CI material faster than direct stratospheric injection 

[Andrew Lockley]

Pengfei appears on the reviewer 2 podcast to discuss this paper

https://open.spotify.com/episode/2qNxBiuHJI5zWET2GXSy9u?si=62YxobEeT7CjNtjch2cWuw&utm_source=native-share-menu&dl_branch=1

I'm curious as to whether one could implement this idea using truck bombs, or possibly air launched bombs like the MOAB 

https://en.m.wikipedia.org/wiki/GBU-43/B_MOAB

Here's a video of a sulphur based thermobaric charge. The plume isn't very sooty, but that can be fixed https://youtu.be/xsWrfWJOu4Q

I'm wondering if you could mix up sulphur powder with inexpensive ANFO booster, and possibly with liquid oxygen, to make a sooty mushroom cloud that is dark enough to lift (in sunlight) to the stratosphere.

Getting the mushroom cloud out the boundary layer should be feasible. Here's a combat video showing a plume that probably makes it

https://youtu.be/7GzDceVdpMI

Here's another combat video, showing differently formulated explosives, giving a much darker plume https://youtu.be/v9r0u3dY48o 

I'd welcome ideas on this, particularly from chemists and engineers with explosives experience. 

Andrew 

[Jessica Gurevitch]

I think it would be difficult to get strong public support for this mechanism, even beyond the challenge of getting (any) public support for SAI. By "difficult" I mean, good luck with that.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jessica Gurevitch 

Distinguished Professor 

Department of Ecology and Evolution
Stony Brook University
Stony Brook, NY 11794-5245 USA

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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[Andrew Lockley]

The difficult bit is getting £100m to design and build a new type of plane.

If you really can do geoengineering with a truck bomb, it puts it in the realm of hobbyists.

Bulk mining explosives are about £2k/ton, sulfur is £30/ton, oxygen costs around £70/ton, charcoal is £200/t

So blasting 1t sulphur will cost you maybe £100 for the primary chemicals and then maybe £20 for the charcoal lifting powder, if the ANFO isn't sooty enough. You'd need a bursting/initiation charge of perhaps 5pc by mass ANFO, so that's £200. Add in another £50 a shot for bulk bags, detonators and ropes to suspend the bag (you don't want to actually blow up your truck), and you're looking at under £400 per 1t of sulfur blasted. 

Even if only half the sulfur makes it to the stratosphere, it's £800/t penetrated. 

Most people have that in their current account, at least on payday. You might need to do a bigger shot to get it up (maybe 100t charges), but it's still not an expensive approach - either per ton, or per shot. 

Andrew