[zbrozek]

I could imagine something a bit better controlled could be ok.

Large areas of solar panels, engineered to reflect as much as they can't use, would be a good double benefit. Excess electricity could be opportunistically used for GHG capture or the panels could maybe flip over and become mirrors.

An orbital umbrella that we could modulate such that we can deal with unanticipated consequences could also be ok.

I'm sure there are tons of other approaches that give control in both directions on reasonable time scales. Obviously cutting emissions Right Now is super important, and megaprojects shouldn't distract from that.

[AcerbicZero]

I agree that geoengineering is exceptionally fraught with potential problems, but perhaps it is time to begin exploring the options at least.

from my own understanding and reading one of the few feasible cooling efforts would be high altitude aerosol dispersal, which again, has serious risk of unintended consequences.

There is also room for a bit more pressure on countries which emit excessive amounts of carbon, that show no signs of slowing down.

[generj]

Solar shades have great potential and the unintended consequences can at least be mitigated. Unlike aerosol dispersal they can be “turned off” semi trivially with onboard thrusters or specialized missions. Cost estimates were at $100 Billion 10 years ago which were doubtlessly optimistic, but Starship will dramatically lower the cost of deploying a few hundred tons of shades.

One risk of not exploring geoengineering is that cheap options for it exist and most countries are technically and economically able to engage in them. If a country feels like the burdens of climate change fall unfairly on them, the option exists to do something drastic.

[jbay808]

Solar panels are mostly black. Do they reflect more sunlight back into space than what was under them?

[zbrozek]

Usually not, and certainly not as currently designed. Hence the notion of flipping to a mirrored side in case of excess electricity, or having some fancy coating stack that manages to reflect everything which is not absorbed by the cell.