My chemistry professor presented a short introductory video to the course at the beginning of the semester. Some army personnel counted down, an artillery shell launched, and a few seconds later a mushroom cloud appeared. So long as the ka-boom weapons keep getting built, the threat of a nuclear war will be real...especially when there are nations who value honor, pride, and religion (not necessarily all at the same time) to an extent that they're willing to spark war.

First, I fail to see the relevance of a 1950s nuclear artillery test to a chemistry class, but that's besides the point.

The number of tactical and strategic nuclear warheads is far lower today than during the Cold War. The US and Russia have sharply reduced their weapons inventories.

Simply having the weapons doesn't necessarily mean they'll be used. The US has had nuclear weapons since 1945. We used two of them. The former Soviet Union has had nuclear weapons since 1949. They never dropped one in anger. Both sides realized that using nuclear warheads was a no-win situation. Some people thought one side or the other could use the weapons and survive but that was only if they struck first and struck hard. Fortunately, saner heads prevaled. Having nuclear weapons makes a nation something to be taken seriously. So far, it seems that every nation that has developed nuclear weapons has sobered up about their use (e.g. India-Pakistan). Some argue that nuclear weapons have kept the wars small and limited in scope. It seems likely that without the threat of nuclear warfare, we would not have gone over 60 years without a major war breaking out.