What a lot of people seem to gloss over is that the southern hemisphere is, for the most part, blissfully uninvolved in nuclear politics and unlikely to be targ

What a lot of people seem to gloss over is that the southern hemisphere is, for the most part, blissfully uninvolved in nuclear politics and unlikely to be targeted. Global wind patterns would dump most of the fallout in the northern hemisphere. Google and Facebook would be gone because there are too many primary data centers in the northern hemisphere but Wikipedia might not even go down. Humanity on the historical level would notice a strange blip. Not discounting the terrible loss of life (I'd be dead along with everyone I know and love) but lesswrong is generally concerned with existential risk, not whether global GDP will be X in 100 years.