What the article doesn't take in account is the efficiency of the technology in 1962. I have read some article and discussed with some former engineers. At that time it is estimated that around 20 to 25 % of the missiles would have gone dud/would have experienced a misfireThe United States had 203 missiles of this type, with a combined nuclear yield greater than 635 megatons, the equivalent of 635,000,000 tons of TNT. By way of comparison, the "Little Boy" bomb dropped on Hiroshima during World War II -- resulting in between 90,000 and 166,000 deaths -- had a yield of around 15,000 tons of TNT.
The Soviet Union had only 36 missiles capable of covering a similar distance, with a combined yield in the range of 108-204 megatons. Although much lower than the long-range missiles held by the Americans, these weapons still represented a nuclear power between 7,560 to 14,280 times greater than the Hiroshima bomb.
IndeedWhat about the nuclear missiles carried by Russian submarines? Article doesn't say a word about that.
The way i see the things : most of the inland big soviet cities would have been turned into glassy rubbles as well as most of the east-west coastal US cities (the hearth of politial and economical strenght of USA). I am not even talking about Europe
203 missiles is enough to target between 30 and 50 cities (due to the misfire/dud probabilities each city was always targeted by between 4 to 8 missiles as there were not MIRV back in those days)
36 missiles is enough to target 10 to 12 cities (Soviets were using bigger warheads to compensate their lack of missiles too)
And that without the sub launched warheads and bombers
In both case the very core of each state would have been annihilated and only cities of less than 40 000 inhabitants would have been sustainable
In both cases as SU and USA were pretty rural, a significant amount of population would have survived the first hits but not the follow up of radiation sickness, crop contamination, diseases due to destroyed health system and millions of decaying bodies, lack of food/clean water and social disorders
As for Europe, the effect would have been more immediate as the european population was more dense