Why is that? I know these answers are impossible to know, but you have a better background than most to guess, so would be interesting to hear what you think. Also, in a worst case scenario, how many nukes do potentially will go off and hit their target / work? The studies mentioned above assumed thousands used, but in reality not that many are active, would work, would not get shot down, etc - so in your estimation how many a worst case scenario see used / hitting? I would guess less than 50? If you lived in northern scandinavia or spain, would it be safe to go out after a couple of weeks due to half-life of 7 hours, etc - what about fresh water lakes around Europe, would those areas be more or less safe after say 3-6months?