[lugorrr]

I am fairly certain that there are measurable cognitive effects at "just" 500 ppm

Well, that would be problematic sooner or later [1].

[1] https://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_m...

[gpm]

Indoors that's problematic today, outdoors we have "awhile" if you make 500 your cutoff, we're only growing at ~2.4 ppm per and the yearly peak is at roughly 420 right now, we can probably count on 20 years before we hit 500 outdoors.

https://www.co2.earth/co2-acceleration