CO2 Concentrations Last 800,000 Years
The atmospheric concentration of CO2 is continuing to increase at about 3.2ppm/year, having surpassed 400ppm for several months in 2014.
Source: Scripts
URL:     http://keelingcurve.ucsd.edu/

CO2 Concentrations Since 1700
Source: Scripts
URL:     http://keelingcurve.ucsd.edu/