[DaveinGermany]

I somehow doubt it. There's been scuffles throughout the ages in various parts of the World all underscored by outside powers supplying arms, ammunition, machinery & in some cases men. It's a form of live proving of weaponry & tactics before issue to their own armed forces or export to others.

Most of the 20th century has been a case in point, S.E. Asia is a prime example, French, American, Vietnamese, (supported by US, Chinese & Russian military tech) although idealogical reasons were the starting point, it became a war of the manufacturers in later years as to whose technology could kill more effectively.

Korea, which never really finished & is still ongoing sans bullets & bombs. Iran & Iraq happily killing each other in the 80's while being supplied & supported by middle eastern allies & the West, who later found themselves in the 90's & 2000's fighting against the very forces they'd equipped & trained. Russians in Afghanistan in the 80's taking a hiding from the Mujahadin (bankrolled, trained & armed by the US). who then went on to fight against the very same Americans who'd kitted them out. Nuclear stand off between India & Pakistan with skirmishes regularly happening in the mountain border regions where terrorist cells of Al Qaida train to fight those opposed to their views & extremist ideals, need I go on?

The above are just a few that come readily to mind, but there's so much more going on around the World, mainly fuelled by religious/racial hatred but all knowingly or not propagated by well meaning/cynical third parties. So in answer to your question, a third World war? No, but an increase of "local" warring & violent civil wars are ever more inevitable.