It starts with a single mushroom-shaped cloud the world hoped to never see again. Retaliation prompts tit-for-tat attacks, each intended to end this latest War of All Wars, until a week or so later Earth begins to shiver beneath a pall of soot and dust. Scenarios mapping and calculating the devastation of a nuclear winter are nothing new, dating back to a time when the Cold War was nightly news. Decades on, we know a lot more about the finer effects of particulates in the atmosphere… – Science Alert