With the way things are going ww3 will be about water. It’s easy to imagine half of Africa, Latin America and parts of Asia to pack and move as a whole.
How would this work? Either the water is on the ground or it is in the air, neither case is a dry world. Where would all the water go to "dry the world"?
When the large fraction of the world population that depends on seafood for their protein loses that input as ocean acidification crashes fish nurseries, do not expect them to adapt peacefully.
So, will WW3 be about access to living space, fresh water or protein? Or all three at once?