I've personally taken an interest into this matter. For there to be a World War Three, it would require some sort of very significant threat towards USA/UK by either the Russian Government, of which there hasn't been since the Cuban Missile Crisis in the Cold war, or a large-scale worldwide terror attack which may be retaliated with Nuclear Weapons. That may cause the war due to potential falldown which may destroy the planet, or due to the upcoming 2012 worlds end prediction, which over 90% of the human race may die, if the predictions by the many ancient civilisationsa and Nostrodamus are correct. This may be caused by Worldwide Market collapse, poverty, disease, natural disaster or... World War Three.