I don't find it horrifying. Not that long ago, CO2 ppm was twice what it is today. Before that, it was twice that. If we could travel through time, we could drop you in that world and you'd be fine, other than the fact that the world would be an incredibly dense jungle. History shows that we're not particularly close to any dangerously high amount of CO2; we were much closer to a dangerous low amount, since plant respiration fails at around 150 ppm, which would probably mean the extinction of most if not all life on the planet. That's for certain; on the other hand, nobody's able to point to anything particularly bad happening at 400 ppm; the earth has already endured far higher amounts with no problem. Being worried about CO2 is a tenet of a modern religious faith.