Unfortunately even recognition of a capability to build such a thing will certainly reduce pressure to rapidly de-carbonize, even the acidification of the oceans is hailed as solvable now by putting vast but affordable quantities of mined olivine them.
Human depredation, mis-consumption and mis-appreciation of natural systems (as well as each other) remain gravely destructive and tragic modern persuasions until the narrative is healed.
Reflectors in on the ground also have the benefit of being controllable.
1) Solar isn't really cooling anything, it's just transferring the heat to the point of use through the grid.
2) There's a lot of square footage of pavement and rooftops before we need to seek out virgin land.
3)Adding any feature to a production of 16 trillion won't be trivial in cost or complexity. Anything besides passive steerage (akin to a solar-windsock) is going to sink the project, IMO. I suspect that once you start adding power, gyros, controls, communication, navigation, etc, it will be more economical/feasable to scale up the size of each deployable shade by 2+ orders of magnitude (4+ by area). Which isn't to say it would be feasible, just more feasible.
Agreed it would be difficult and heavy to add minature gyroscopic and solar cell, comms and control unit to the 16 trillion disks proposal, since they are just 60cms wide. That plan seems basically like throwing confetti into L1, where it might get drifted away by solar ejections, out of stable orbit, in matter of years.
Since each of those disks is 1 gram and about 0.25 square meters, that scheme involves total of 4 trillion square meter shades orientated randomly. If shades are squares for simplicity and 8 meters in diameter, so 64 meters square and similar material would be 256 grams, add some stiffening and a control unit for say an extra 150 grams. Maybe a clever unfolding feature like an insects wing. Its a bit more material to launch but probably less than double at some control/shade ratio, and the tracking shades will block light about 30% more effectively than randomly orientated ones. Works out around 50 billion of the 400gram 8 meter wide shades with mini solar-comms-gyro units to produce. So I'm still overconfident in the practically of this kind of scheme, especially since cost to space has been minaturised since they previously had expert attention.
I have to admit its just one of those hunches Im hawking of late, cheers for following :)
For example, the author does assume 1gram (2ft diam) shields, but also specifies the necessity of precise angular orientation, and relatively modest location control / steering. This is to be accomplished by an unspecified number of "control satellites" using aimable mirrors and passive radiative pressure, which keeps the discs simple and the weight at 1 gram. Required disc area is ~7x the required total shading area, due to indecent angle and required transparency and spacing. A new gps-like network of "navigation beacons" will also be required to maintain spatial reference. He then says that to track individual disk locations/ orientation, that each disc needs a GPS-like nav receiver, 2 cameras, some processing/ communication ability, and a power supply, presumably solar. But he doesn't account for (or even reconsider) that there will be added weight and cost due to this.
He also doesn't consider the cost of inventing, manufacturing, and deploying the control satellites or the new type of nav beacon network, or even estimate how many of each will be needed. (GPS tech won't work, but if he knows that, he doesn't state it.)
There's other questionable assumptions, like a launch cadence of every 5 minutes for 10 years to leo, and that cost of launch will roughly equal cost of fuel due to the scale.
He also estimates the method of transfer from leo to L1 will require delta-v of 1km/s and assumes it will be solar powered / ion propelled, but leaves it at that, also without scope or cost.
It's interesting, but less convincing than I expected, given all the missing details, and also makes me more convinced that risk assessment, management and mitigation haven't thoughtfully been considered. That said, the shading, geometric layout, and required material properties calculations are quite impressive.
+/- 16 trillion self-powered, locally communicating "cellular" elements, each with some minimal sensory and processing capability. Add to that the mobility presumed by the author, and the fact that it is literally designed to block the sun, and you've got everything you need for a matrix rewrite...
The control coordination of trillions of L1 satelites doesnt strike me as a huge challenge to people already working in similar fields. I do some work on simulations and read about related technics. Control units just get individual and group call codes that they can respond to, in timed windows if helpful. A number of manager satellites beam signals to sectors and listen to responses. They could likely often pinpoint individual transmissions themselves with modern radar style tech, although trillion is a large number, sheilds will rarely eclipse one and other because they would be very dispersed and relatively small. They dont have to relay all messages individually through neighbours but perhaps could. The options for implementation are extensive but I believe familiar to network designers. They don't really have AI processing to do, its just a matter of maybe reporting their neighbors numbers so position can be determined and relayed so they know where to 'light-sail' and can receive schedules for when to let light past - if that becomes necessary or is deemed advantageous. Im just rambling but there are loads of possibilities for how to organize them. As a multi-node processor it would be rather slow because of the average latency between nodes being many kilometers, rather than millimeters to meters in a supercomputing cluster.
Personally, I'm terrified by how people here suddenly are so enthusiastic about the sunshade, without even knowing its side effects, when the problem can be solved at its source.