I believe that World War III will happen, I'm not sure when or where, but with the way world economies are going, and the fact that riots are breaking out in 3 separate countries, it will happen. I should also point out North Korea and China's increasing hostility toward the United States, and Russia's rising tension with the European Union. Either way, the odds are that all nations involved would go nuclear, and no one would win.
While it is true that peace is an option, you have to take into account backstabbing politicians, warmongering terrorist cells, and ultra nationalists that could, if left unchecked, could cause the war. And it could even be started on accident! Who's to say that all wars were caused by madmen or greed? Peace, at least in this day and age, is impractical. As Sun Tzu said: "War is used to create peace, while peace is used to prepare for war". Though the least of our problems is political, we could end up with a second cold war at the bare minimum. Nobody wants another cold war, I'm sure.