3rd War war will be between all the countries, because it is the war between world's countries definitely.
But initiators of this war will be China, Japan and US (probably). We should erase Russia, West and East Europe, also we should erase Afrika, Australia and South Amerika, because they all have no resources and points to start any kind of war. Islamic states and Izrael are able to join that war, or even provocate it. Far East lands will be initiators of the 3rd World War, and they will enslave many other lands with their new automatized systems - I mean electronic controls over each citizens. They've already been doing this celling, for example, their products and apps. And we won't stop them easily, because it will be a massacre war with tiny nuclear weapons. All what we can do now is to start looking for John Connor.
I say south-east Asia, most likely the Philippines.
SE Asia has the worst destruction of marine life
which is the last open and free resource that
is not owned - thus it is fair game for conflict.
The Black-sea and Med are also candidates but
those countries are less reliant on marine resources.
China building islands could be a serious problem
because it is a loophole in international law,
and even building a 1m high rock entitles them
to about 1000km^2 of fishing space.
The days of free oceans are getting less.
And its about time too because only if you
own something is there incentive to look after it.
The number of fish in the sea is 1/10th of what
it was 200 years ago, but the human population
is 10x bigger. Something's gotta give.
The only solution is global govt with one major
enforceable agenda: ZERO population growth.
It sounds fairly authoritarian, but the alternative
is just infinitely worse. Marine conservation would
be the 2nd priority.
