WWIII Will be due to over population.
-Due to over population food/water/energy etc. all start to boil over and become problems that need to be solved by the dominate groups to keep their control, their image of being the best.
Our once great city's are falling apart the people are being over taxed to keep them up and running. The financial sky is falling and is based on credit not really money. I think the Disney Dollars I got as a kid have more value now.
Don't believe me just look at history this had happened time and time again.. Populations get to large then war/famine/sickness or whatever.
What is the cause of war.... "..dominating groups control foreign policy and make wars to maintain their dominance, what chance is there that these groups can be persuaded to avoid war by giving up their control? The answer is, practically none."
http://tmh.floonet.net/articles/warcause.shtml
So at this point we are just arguing and dealing with the semantics of what will be blamed for as the cause of WWIII
As for WW4 .. that won’t happen because by then the worlds computers will be connected and running Windows crash allot service pack 3000. And nobody will be able to get past their blue screens to launch anything .. Well that and so 12 year old in china will finally be able to say he really did hack the planet.. :P
Or maybe it will be over some girl crying over a can of beans..