I think the crisis will be contained to the poorest parts of the world. Especially the tropics. This area is going to be the first to bear the brunt of climate change related problems.
I dont foresee Global wars happening. The politicians are too smart for that. They will try to contain the damage to the extant that the richer countries ( US, Europe, Australia ) are not affected much. Ofcourse there will be shortages as global supply routes are going to be disrupted.
The most thought provoking scenario here is going to be what will happen with China. Maybe not being a democracy will prove to be a blessing in disguise for it. Having a pragmatic group of men leading the country is the best option in the face of upcoming doom. China may shed a lot of weight ( population), but it may just survive, because of its largely monoculture and more or less obedient population.
I see much of Africa, SouthEast Asia to completely gone by the next 100 years. They will be left alone by the rest of the world to fight the battle of survival, and the odds wont be great.
MiddleEast is already ravaged, but they may continue to survive because they have oil.
Most rich countries ( the leaders I mean ), may not be very displeased with the fate of the poorer nations. Because as far as they are concerned mass deaths in poorer nations is only going to reduce the carbon emission load on our planet.