[bryondowd]

Engineering aside, you could perhaps position this shadow strategically over some place that is uninhabited and which wouldn't cause too much weirdness in our climate. Or perhaps many small shadows. My guess would be that you would want them over the oceans. Or maybe Kim Jong-un's house.

Alternatively, if geostationary is too high up, perhaps just wrap them at a particular latitude near the equator, spaced out so they just make an effect like a perpetually cloudy day. You then just have to keep your solar panels and needy crops off that latitude.

[marcosdumay]

If you want a big enough effect to detail global warming, you'll need a big enough effect to change the climate. There's no place it "wouldn't cause too much weirdness in our climate".

If you place them over the equator, you've just destroyed the places with the highest plant growing and solar energy harvesting potential. Granted it is not the most used place of the world today, just the one with most potential.

If you place the shadows over the oceans, you'll completely change the environment there, and help destroy its bigger species, that we eat too.

[bryondowd]

Well, the whole point is that the Earth, due to greenhouse effects, is taking in too much sunlight compared to what it is radiating back out into space. So yeah, you're going to be reducing the total potential harvestable sunlight getting to Earth. However, that's not really a constraint for us at the moment. We just care about tapping sunlight in places near where there is a demand for energy. So, you could probably find a nice band around the Earth where the inability to place highly efficient solar panels wouldn't be missed sorely.

By 'too much weirdness' I'm referring to instigating entirely new and dangerous weather patterns. Ideally, you could keep the weather roughly the same, with the lowered temperatures disbursed enough to create a measurable but not easily noticeable effect.

And we're also not talking about plunging the area into permanent darkness, we're talking about enough reflection to reduce average global temperatures by a few degrees (or at least prevent them from rising further). I expect that could be done, if spread out enough, without enough of an impact on any one area to impact local environments.

Of course, this is all just theoretical. I doubt it's actually a reasonable course of action. I just don't think this is why it isn't.