I am not sure. As far as I remember, all wars have been caused by a crisis of one kind or another. When times are good, people are in the mood for brotherly love, open borders and all that jazz. When times get tough, all the tiny differences suddenly come to the fore. I suspect that rather than bringing people together, "the necessity of fleeing raging fires...hurricanes...etc" will become the catalyst for more strife. "We have nothing left, but those over there have everything. Let's go and take what is rightfully ours!"

Religion is not the main reason for modern conflicts. It is just a convenient dividing line between "us" and "them". People need such a line to justify the hostility and they grab at the first obvious difference they find. Skin colour, religion, accent, football team affiliation... whatever.