We Need To Keep A Couple Of Very Important Dictums In Mind Here

As we do what needs to be done to save the planet.

The thing to start with, naturally, would be what any doctor could tell us: first do no further harm. Which means you better be looking very carefully at what the long term effects of your measures might be, beyond just lowering the amount of sunlight getting through the atmosphere.

Which is why I thought the second dictum I would operate under, in thinking about this sort of thing, should be that we ought to have a design parameter in place that establishes the ability to dial, whatever the effect is that we relying on here, up, or dial it back down again.  And in that vein using things like mirrors in orbit provides a good example of (forgetting for the moment the considerable effort it would take to put that many mirrors into orbit, or even what that might do to orbital congestion in general).

This is why my bias towards lighter than air constructs seemed quite appropriate now. And if you started with the elegantly simple starting point of "Lift Doughnuts," as I have described them, you could indeed create very large, fairly high altitude, lighter than air support platforms that could alternately block sunlight, collect solar power, and be scaled up or down in effect in relatively quick fashion; if they were assembled correctly, of course, within a well thought out assembly, and maintenance process. And I am talking about a very large, as in many square miles large, actual floating object that could get to altitudes where we might even be able to bring very cold air down from.

The biggest problem, certainly, with all of these schemes is that they will take tremendous amounts of infrastructure, of one type or another, to make happen. And in that we must also face the fact that this sort of thing simply can't be taken on without a corresponding change in how we operate as a society as a whole. How could it be otherwise when we will also have to tackle the population problem as well, for to do otherwise would doom any efforts to save the planet environmentally, no matter what you did to limit sunlight, or increase ice, at the poles. Which is also why we will have to mobilize as a nation, just as if this were another great threat to our existence; even if it's not a war against tyranny or Imperial domination. And until we recognize that, as well as to realize that Capitalism won't be able to take it on, we will just be spinning the mental wheels in useless conjecture.

The Machines That Could Darken the Sun to Stop Climate Change