https://penntoday.upenn.edu/news/continued-CO2-emissions-wil...
Combine this with wetbulb temperatures which force everyone to stay in airconditioned indoors for weeks or months in large part of world (this too is supported by climate science). Fantasies? I hope so but expect the worst.
A single study that predicts brain damage from CO2 “by the end of the century” is pure speculation at this point. The link you shared even says it’s still very unclear what the effect is.
I’ll say it again; the actual science says that climate change is a serious problem. It doesn’t say that we are headed into the apocalypse in the next decade.
The actual paper linked from the article links to some research like: "systematic relationships were found between most of the cognitive function scores and CO2 concentration, including from 550–945 ppm". Thinking that in 20 years we could go over 550ppm outside certainly isn't a fantasy, or?