No, we won't all die, but in some places a lot of people will either die or move somewhere else. When droughts get even more serious than they already are, and when there's no options to irrigate, people will start migrating in ever larger numbers, and to be fair, who can blame them.
Everywhere where subsistence farming is still the mainstay economic activity people won't have a choice when climate change causes crops to no longer grow, and domestic animals die in droves. Future wars over the available water will only serve to make things worse. Egypt/Sudan vs Ethiopia is already a powderkeg in that respect.
So yeah, 50 years from now (it won't even take a 100) migration won't be a minor issue anymore. You wouldn't say it's still a minor issue today if you follow politics, but you ain't seen nothing yet.
Moreover, desertification in Spain and elsewhere is well underway already.
And further ahead, maps will start looking very different from today. Melting polar icecaps will see to that. Luckily the last climate change deniers will die long before that happens.
It is very questionable though whether the next few generations will find a solution to the mess we are leaving them with.
The problem might well be that we already passed a tipping point, where further heating up beyond 3 degrees Celsius becomes unavoidable.