Joe Farah looks at the historical record and concludes that, from a chronological standpoint and with an eye toward the Islamic jihad imperative, this is actually World War I. From [1] WND, with thanks to Clearsight:

I think we've mis-numbered the global wars so far.

I see this conflict – one that has defined history for the last 1,400 years – as World War I. This is the real Great War. It's far bigger than the conflicts that took a few years to settle. And it's not going away anytime soon.

This war is so big, some people can't even see it.

[...]

There exists a religious totalitarian ideology that seeks global hegemony.

What we see happening in the Middle East today is the struggle in a microcosm.

[...]

This is the way it has always been – since Muhammad first got his demonic visions in the desert. Ever since then, radical adherents to his message have been on the march – beheading, converting by sword, wiping out entire villages, raping and pillaging. Sometimes they are set back – for years, decades, centuries. Sometimes they are on the ascendancy – for years, decades, centuries.

This isn't World War III or World War IV. This is World War I.