[1] https://en.wikipedia.org/wiki/Stratospheric_aerosol_injectio...
From what I understand, it will help... eventually.
If ambient temperatures come back to normal, then the ocean won't absorb as much CO2.
It would be better if we could come up with a way to neutralize / sequester the co2 already in the ocean.
Basically, artificial green-sand beaches which absorb CO2 as they weather.
Carbon pricing sounds like a cheaper and a more direct solution addressing the cause of the problem (more greenhouse gases in the atmosphere) instead of its effect (temperature rise). What could go wrong?
If feasible at all, make a part of those shades photovoltaic panels, and beam the energy back using microwaves, as that would provide an extra incentive to launch that (GEO might be more useful for that kind of setup, I have no idea what deltav it would take to transfer to/from both, but you could use ion thrusters since you have on-board power).
Better to send up 10,000X dumb shades with random orientation and spin. Not only are the dumb ones much lighter, they're proportionally much cheaper too, since they're basically just structured aluminum foil rather than needing thrusters, reaction wheels, computers, etc.
Would be interesting to keep inflow the same and reduce outflow, but I have no idea what I am talking about.
You don't really make the atmosphere thinner by removing CO2 or methane...they are trace gasses relative to N2 and O2, CO2 is less than a .05% of the atmosphere, IIRC. So, you mostly want to prevent heat from hitting the Earth, or decrease the absorption (increase albedo), or you want to remove the heat-trapping gasses that will continue a warming cycle by trapping the heat we do get.
I think space sunshade's a decent idea, but we still need very aggressive decarbonization, as CO2 is very bad for the ocean, nevermind the heat trapping.
Infrared radiation only comes from things that have been heated (mostly) by that visible light. Any light reflected back into space without being converted to heat is energy that is somebody else's problem.
Allowing CO2 to increase without bound would eliminate the fisheries billions of people rely on for their protein.
What happens when those space shades get hit by micro meteorites causing them to alter or de orbit?
I don't think there's a big micro meteorite problem at the Lagrange point, but if there were for arguments sake, then you need to plan for it and have a way to replace shades that get knocked out of position. It's not like the whole system would fail if you lose one shade. That's what engineering is about, planning for all the likely eventualities.
"0.6-meter diameter and a thickness of about 5 micrometers. The mass of each disk would be about a gram..."
Absolutely nothing.
I wonder if we will one day regulate our climate on earth by shading hot areas and pointing mirrors at cold ones. There are all kinds of knock on effects of doing that, but it seems like a human thing to do. Modify the environment instead of adapting to it. That's kind of our thing.