"More people will die almost immediately than were killed in the entire Second World War.
“…Up to 36 million tonnes of smoke and soot from subcontinental cities incinerated by even modest nuclear warheads will be blasted high into the upper atmosphere, spread around the globe and darken the skies.
"Planetary average temperatures will drop by at least 2°C and by as much as 5°C, and for the next 10 years regional temperatures could plummet to levels characteristic of the last Ice Age. Rainfall will diminish by 15% to 30%, and so will the productivity of the oceans, terrestrial forests, grasslands and croplands.
“This would be enough to trigger mass starvation around the rest of the globe, according to the scientists’ study, published in the journal Science Advances.”
See: https://climatenewsnetwork.net/nuclear-war-could-ruin-earth-and-leave-only-losers/