The atmospheric concentration of CO2 in parts-per-million (ppm) is sourced from the U.S. National Oceanic & Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL)’s Global Monitoring Division (GMD):
Dr. Pieter Tans, NOAA/ESRL (www.esrl.noaa.gov/gmd/ccgg/trends)
The globally averaged marine surface annual mean data provided by ESRL are plotted in the atmospheric concentration (aka, “ppm”) graph for 1990-2007. The annual data have an uncertainty of +/- 0.10ppm, which reflects the mean of the standard deviations for each annual average estimated using a Monte Carlo technique.