↑Source for figures: Carbon dioxide, NOAA Earth System Research Laboratory, (updated 2013-03). Methane, IPCCTAR table 6.1Archived 2007-06-15 at the Wayback Machine., (updated to 1998). The NASA total was 17 ppmv over 100%, and CO2was increased here by 15 ppmv. To normalize, N2 should be reduced by about 25 ppmv and O2 by about 7 ppmv.