The State and the Variations of Greenhouse Gases in the Atmosphere
A full global analysis completed for the three main greenhouse gases shows that in 2017, globally averaged mole fractions of CO2 were 405.6 ±0.1 ppm, CH4 at 1859 ±2 ppb and N2O at 329.9 ±0.1 ppb. These values constitute, respectively, 146%, 257% and 122% of pre- industrial levels (pre-1750).