Heh, I came back to this computer after being away from it for a while, and still had this thread up. Anyway, the answer is:
Mirrors.
In sun or earth orbit, very thin, very big. Doable (but expensive) with current technology.
Now, “whether it’s worth it” is debatable. In the case of a temperature rise (for whatever reason) no greater than the peak of the previous interglacial period, I’d say “probably not”. In the case of the next period of glaciation, due any time now (in terms of geologic time), “yes, no question.” In the latter case, with no attempt to alter the natural process, I don’t think we’d lose the human race, unless a large nuclear war is triggered, but, we’d likely lose 2-5 billion people.
Do we know how much incoming sunlight to block or add? That’s the hardest question...
“Do we know how much incoming sunlight to block or add? That’s the hardest question...”
Nature has already established that ratio.