Monthly mean atmospheric carbon dioxide at Mauna Loa Observatory, Hawaii

The carbon dioxide data, measured as the mole fraction in dry air, on Mauna Loa constitute the longest record of direct measurements of CO2 in the atmosphere. They were started by C. David Keeling of the Scripps Institution of Oceanography in March of 1958 at a facility of the National Oceanic and Atmospheric Administration (Keeling, 1976). NOAA started its own CO2 measurements in May of 1974, and they have run in parallel with those made by Scripps since then (Thoning, 1989). The Scripps data are in blue, the NOAA data in red. The black curve represents the seasonally corrected data smoothed with a 6-month window (Thoning, 1989).

Click for recent trends in carbon dioxide at as measured by thermometers over time that corresponds readings at Mauna Loa, Hawaii and from the global network.