100 years

First of all, everything you described is coming much sooner than that. Divide it by five and even that's conservative imo.

people will likely witness the disintegration of our current technical civilization. Because 3 degrees warming is way too much for a technical civilization to survive.

It seems like maybe you have a fundamental misunderstanding of why climate change is going to kill us. Being a "technical civilization" isn't relevant to whether we survive it or not. We're talking about ecological collapse, and conditions that the human body literally cannot survive in. Like physically incapable. "Technical civilization" or not.