Here is some info from NASA....
https://climate.nasa.gov/evidence/
While the graph detail may be correct the hype with it is somewhat misleading. CO2 levels have been significantly higher, up to 7000ppm, it was also one of the Earths most prolific ages of the Earth's history. Scientist are already saying with the minor increase in CO2 from dangerous low level of CO2 to 400ppm there is a increase in vegetation and showing the positive side of an increased CO2 level.
But just what health effects does CO2 have on us?
The levels of CO2 in the air and potential health problems are:
250 - 400 ppm: background (normal) outdoor air level.
400 - 1,000 ppm: typical level found in occupied spaces with good air exchange.
1,000 - 2,000 ppm: level associated with complaints of drowsiness and poor air.
2,000 - 5,000 ppm: level associated with headaches, sleepiness, and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
5,000 ppm: this indicates unusual air conditions where high levels of other gases could also be present. Toxicity or oxygen deprivation could occur. This is the permissible exposure limit for daily workplace exposures.
40,000 ppm: this level is immediately harmful due to oxygen deprivation.
Poll