As more and more countries acquire nuclear weapons capability over time, does the risk of Earth's destruction increase?

This is an interesting question, and it can actually be thought of quite simply.

Imagine, in your neighborhood, there were originally only two households with hand grenades, and these were the wealthiest and largest houses in the community (like the US and Russia). Although these two households didn't see eye to eye and constantly postured in their yards, neither dared to actually throw a hand grenade. Because they both knew that if one threw it, the other would immediately retaliate, and the end result would be both households being wiped out, their houses, gardens, and swimming pools all blown to smithereens. This is the so-called "balance of terror" or "mutually assured destruction" (MAD). Although everyone was on edge, life could still go on.

Now, the situation has changed. As time passed, more and more households in the neighborhood, regardless of the size of their homes or their domestic harmony, acquired hand grenades through various means.

So, is this neighborhood safer or more dangerous now?

The answer is obvious: it's definitely more dangerous. There are several reasons:

1. More 'irrational' players: The original two households, though rivals, were at least 'respectable people' with significant assets. They would repeatedly calculate gains and losses before acting and were unlikely to do something foolish that would overturn the whole table. However, among the new neighbors who acquired hand grenades, some might have constant domestic disputes, some might have explosive tempers, and others might even think, "If I'm not doing well, no one else should either." With more 'players' like this, who knows when someone might lose control over a trivial matter?

2. Greatly increased chance of accidental discharge/escalation: The more items there are, the greater the possibility of something going wrong. Previously, there were only two safes; now there are a dozen. Perhaps a neighbor's security system is old, or a child plays with it unknowingly, or their alarm malfunctions, making them think they're under attack, and in a panic, they throw it first. The more participants there are, the exponentially higher the risk of such accidents and misjudgments becomes.

3. Local conflicts could escalate into global disaster: Previously, the confrontation was mainly between the two major powers. Now, it might be Zhang San and Li Si from the east side of the neighborhood arguing over property lines (like India and Pakistan). They might have originally just had a verbal spat or a fistfight, but now they both have hand grenades strapped to their waists. Once the conflict intensifies, if one side gets desperate, they might very well use this 'ultimate weapon,' and then it would no longer be just a matter between two households; the entire neighborhood could be dragged into it.

Of course, some might argue that precisely because everyone has hand grenades, no one dares to make the first move, thus promoting peace. This argument might hold true between 'two rational giants,' but when the 'nuclear club' grows in number and its members' backgrounds become increasingly complex, that fragile 'balance of terror' becomes extremely unreliable.

In summary, nuclear weapons are like the Sword of Damocles hanging over all humanity. The more swords there are, the more likely the ropes are to break due to various unexpected reasons. Therefore, the more countries that can build nuclear weapons, the more dangerous our 'global neighborhood' undoubtedly becomes, bringing us one step closer to the brink of destruction.