Further climatic disruptions will make the already dire situations in many countries untenable. That situations like that do not tend to improve by unilateral actions of their neighbors if the threaten to make a barely acceptable situation even worse.
https://www.thetimes.co.uk/article/the-first-water-war-is-un...
I guess I'm in a sarcastic mood today. Yes, of course that will cause mayhem. It's one of the reasons I see climate change as such a threat to our all civilization. We're fearsome tribal creatures and the coming waves of desperate peoples will almost certainly play into the hands of nationalist fearmongers and firebrands.
I wonder if we will see some kind of -literally - ecofashism rise from that.
The worst part is, once the killing starts, people will rationalise it to themselves, saying "We didn't have a choice".