Atmospheric Carbon Dioxide

Why is this warming not a natural cycle?

projected rise in atmospheric carbon dioxide

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.

Click here for the Mauna Loa CO2 annual mean data.

Contact: Pieter Tans, ESRL/GMD, ph. 303 497 6678, Piete


C.D. Keeling, R.B. Bacastow, A.E. Bainbridge, C.A. Ekdahl, P.R. Guenther, and L.S. Waterman, Atmospheric carbon dioxide variations at Mauna Loa Observatory, Hawaii, Tellus, vol. 28, 538-551, 1976.

K.W. Thoning, P.P. Tans, and W.D. Komhyr, Atmospheric carbon dioxide at Mauna Loa Observatory 2. Analysis of the NOAA GMCC data, 1974-1985, J. Geophys. Research, vol. 94, 8549-8565, 1989. 1989.

Search this site.

NOAA/ESRL Global Monitoring Division
325 Broadway R/GMD1
Boulder, CO 80305-3328