Its not really a war assorted nasty local conflicts plus global terrorists vs the west which mostly goes on as normal.
this is true but i think there is a deeper layer of factors that interconnect the disparate conflicts
if we are saying that to warrant being called a World War it has to follow a template set out by the other 2, then clearly it isnt that, and hopefully that mass allied states vs allied states war will never rear its head again.
But I think it is useful to think of whats happening as a World War - or at least a Something Or Other War, as I think it forces the need to look at the interconnectivity of what is happening and the scale at which its occurring.... Putting together all the uniting factors is not a straightforward thing, but I think is helpful to understanding.
I'll have a go at trying to list they key factors as I see them - nothing groundbreaking here - all which I think feedback into one another and show no sign of being resolved any time soon:
*Islamic fundamentalism / Caliphate building: ISIS the most pronounced form of that at present, but clearly there are groups from west africa to afghanistan on similar missions
*US led Western intervention and proxy wars - Western forces are continuously involved and will continue to be, directly with troops, from the air, and through funding proxies
*The failing and falling of pre-existing dictatorships - the Arab Spring phenomenon has different roots - general poverty and frustration with despotism being a key one, but i think the instability created by the US led invasions also helped create the climate and the resulting post-dictatorship has now opened up the space for more warring
*Redrawing of borders - one effect of the European-centered world wars was the chance to redraw borders...Id expect that its just a matter of time before many of the borders of many African and Middles Eastern states are redrawn
*Resources - oil, water, land grabbing...solar? Lots of competition for them
*Ideology - a dramatically broad range of competing ideologies and expectations of normality
*Terrorism beyond the main theaters - small acts of asymmetric warfare (like in Paris) designed to stoke the fires further
All of that seems to feedback into the other and I cant even begin to imagine an end to it. Maybe World War is the wrong term, but I think whats happening can be helpfully compounded.