leading to all out war and global catastrophe.

I doubt it.

Unlike your typical nice bar brawl, not everybody is actually that eager to get involved in an exchange of nukes, and alliances get sometimes weaker when the risks get higher.

I wasn’t getting into the literal size of bomb impact areas vs global surface area.

Of course you are free to build your opinion on whatever speculation you like the most.

Did you know that a good share of all American nukes are mounted on short range missiles that can travel only 100 km or so? Some people were considering funny scenarios there…