In the US, Europe, and Russia, sure, it’d be the end of civilization. However most of South America, for example, would continue relatively unscathed, especiall

In the US, Europe, and Russia, sure, it’d be the end of civilization. However most of South America, for example, would continue relatively unscathed, especially countries like Argentina that are agriculturally self sufficient and of no strategic importance to Russia or the USA. Same for New Zealand, parts of Australia, much of Asia, and so on. Nuclear also wouldn’t affect undersea fiber optic cables so chances are something resembling the Internet would still be around. Personally I would give civilization pretty good odds.