To your first question: Yes, revolution definitely is possible and it already happened multiple times throughout history. Of course revolutions most times do not end in anarchy being obtained.
To the second question: I cannot see how anarchists would be different from anyone else in this regard, so I think they are. Although I also think that those seeking to prevent revolutions are better at it.
To your third question: I do not believe that any global event can culminate in global anarchy. How exactly should one achieve that? You would need a massive shift in how people think for there being no big groups that would revert anarchist achievements and also there is the problem of how one would coordinate anarchists on such a scale.
Most anarchists I know are pacifists also, so I don't see how those would be fine with a global war (and a global revolution means war, I am certain of that).