Annihilation
It would be total geographic annihilation over most of the Northern Hemisphere,
caused by the interchange of huge nuclear weapons by Russia and the USA.
The map image shows the enormous area of damage caused by the impact of just a single Russian 25 Megaton Tsar Bomb if dropped on London.
An area within a 30 mile radius of the impact point would be annihilated and within a 10 mile radius would be vaporised in milliseconds.
Life in the current and future nuclear age is suspended on a tightrope of annihilation.