3.6: Some take-aways
Again, simply reviewing the technical literature on a topic is not an endorsement of deployment, or even of serious engineering development. Nonetheless, in early-stage solar radiation management research, I was pleased to see more chemically benign particulate formulations (e.g., chalk) being researched, which might not damage the ozone.
It was also encouraging to note some of the theoretical advantages of marine stratus brightening: it is fast to turn on and off, can be locally controlled, only involves spraying sea water, and the cost and number of boats theoretically needed seems manageable. But there are a lot of scientific unknowns as to how well it could work, still, and how best to build it and run it.
In addition, in the literature, there is ongoing modeling and analysis of potential effects of solar geo-engineering on key variables like precipitation patterns and crop yields, regional inequalities in effects, and so on, for the stratospheric aerosol approach. So those key issues are not being ignored by researchers studying this.
Solar radiation management still seems like a fraught area overall — in terms of severe governance challenges, potential moral hazard issues, and the need to deal separately with ocean acidification and other non-temperature effects. That doesn’t make it unimportant to flesh out at a scientific and technical level, as an emergency adaptation strategy. But those issues are serious.
Because even solar geo-engineering might not be able to reverse catastrophic collapse of the Antarctic ice sheets, additional schemes to preserve the ice, or to actively lower sea level, need to be studied as a backup of the backup emergency option.