Gao, Ru-Shan; Rosenlof, Karen H.; Kärcher, Bernd; Tilmes, Simone; Toon, Owen B.; Maloney, Christopher; Yu, Pengfei (2021): Toward practical stratospheric aerosol albedo modification: Solar-powered lofting. In Science Advances 7 (20). DOI: 10.1126/sciadv.abe3416.

"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."

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Harrison, R. Giles; Nicoll, Keri A.; Tilley, Douglas J.; Marlton, Graeme J.; Chindea, Stefan; Dingley, Gavin P. et al. (2021): Demonstration of a Remotely Piloted Atmospheric Measurement and Charge Release Platform for Geoengineering. In Journal of Atmospheric and Oceanic Technology 38 (1), pp. 63–75. DOI: 10.1175/JTECH-D-20-0092.1.

"Electric charge is always present in the lower atmosphere. If droplets or aerosols become charged, their behavior changes, influencing collision, evaporation, and deposition. Artificial charge release is an unexplored potential geoengineering technique for modifying fogs, clouds, and rainfall. Central to evaluating these processes experimentally in the atmosphere is establishing an effective method for charge delivery."

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Lee, Walker Raymond; MacMartin, Douglas G.; Visioni, Daniele; Kravitz, Ben (2021): High‐latitude stratospheric aerosol geoengineering can be more effective if injection is limited to spring. In Geophysical Research Letters. DOI: 10.1029/2021GL092696.

"We demonstrate that spring injection produces approximately twice as much summer AOD as year‐round injection and restores approximately twice as much September sea ice, resulting in less increase in stratospheric sulfur burden, stratospheric heating, and stratospheric ozone depletion per unit of sea ice restored. We also find that differences in AOD between different seasonal injection strategies are small compared to the difference between annual and spring injection."

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"It has to be clear that at best SAI would be a complement to emission reductions, which have to be the absolute priority, and probably carbon dioxide removal. SAI could reduce climate change impacts, but it would not contribute to the ‘solution’."

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