My two cents about how catastrophe will happen.
People living in rich countries will become the (well deserved) scapegoats of the millions who have born the brunt of starvation, poverty, and loss of resources for decades while we gorged and got fat (and then spent more millions in drugs to get thin again) on rich food and sent our children to posh schools so they would continue to use most of the resources in this dying world.
In my opinion the worst suffering is not going to come from the heat, the cold or the lack of drinking water.
It's going to come from the reckoning of so many strong, angry, rightfully vengeful suffering people who will take over all we have been hoarding, all that electronic money, all that bitcoin will vanish into the thin air it was created from. And the younger generations, whom ironically did not cause this, will pay the ultimate price.
I laugh when I hear people complaining about "the boat people". It's not them taking over, or "Islam taking over Christianity" we should be worried about. It's about hoards, masses of the fed up people who will eventually come for us,when their world becomes a tiny bit more uninhabitable than it is now. Which will happen very soon.
Heads will roll, and they will be our children's. We are the Elon Musks for the starving world. And they won't forgive us our obscene lifestyle while their children starved.
The recent extreme, unbelievably fast changes in the world have terrified climate scientists. The only reason I'm not terrified myself is that I've accepted nothing we do will be enough now (not that we're doing anything significant, mind you), so I'm just going to enjoy life as I know it as long as it it lasts.
Oh, and that I chose not to have children. I'm immensely grateful for that.