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Atmospheric Carbon Dioxide Record from the South Pole

graphics Graphics   data Data


R.F. Keeling, S.C. Piper, A.F. Bollenbacher and J.S. Walker
Scripps Institution of Oceanography,
University of California,
La Jolla, California 92093-0244, U.S.A.

Period of Record



Air samples are collected biweekly at the South Pole in 5-L evacuated glass flasks exposed as triplets. From 1957 until October 1963, 5-L glass flasks were exposed as singlets or pairs biweekly. Between 1960 and 1963, continuous in situ measurements of atmospheric CO2 concentrations were made. The data presented here are derived from both the flask sampling program and the continuous sampling program. Greater details about the sampling methods used at the South Pole are described in Keeling et al. (1976) and in Bacastow and Keeling (1981). Air samples collected at the South Pole are analyzed for CO2 concentration at SIO through the use of an Applied Physics Corporation nondispersive infrared gas analyzer with a water vapor freeze trap. In March 1983, CO2-in-air mixtures prepared by SIO replaced CO2-in-N2 as the calibration gases used to ascertain instrument sensitivity, detect possible contamination, and determine CO2 concentrations (Keeling et al. 2002).

For air samples collected at Barrow, Samoa, and the South Pole to be considered indicative of uncontaminated background air, the replicate flask samples must agree within 0.40 parts per million by volume (ppmv). Data are in terms of the Scripps "03A" calibration scale.

Map showing location of the South Pole, Antarctica

South Pole, Antarctica
Ice- and snow-covered plateau
89°59' S, 24°48' W
2810 m above MSL


Precise measurements of atmospheric CO2 at the South Pole have been obtained by Scripps Institution of Oceanography (SIO) researchers since 1957. This record is based primarily on biweekly flask sampling.

The SIO CO2 curve from the South Pole shows that annual averages of the fitted atmospheric CO2 concentrations rose from 314.82 ppmv in 1958 to 380.42 ppmv in 2007. This represents an average annual increase of 1.34 ppmv per year.


  • Bacastow, R.B., and C.D. Keeling. 1981. Atmospheric carbon dioxide concentration and the observed airborne fraction. In B. Bolin (ed.), Carbon Cycle Modelling, SCOPE 16. John Wiley and Sons, New York.
  • Bacastow, R.B., J.A. Adams, Jr., C.D. Keeling, D.J. Moss, T.P. Whorf, and C.S. Wong. 1980. Atmospheric carbon dioxide, the Southern Oscillation, and the weak 1975 El Niño. Science 210:66-68.
  • Conway, T.J., P. Tans, L.S. Waterman, K.W. Thoning, K.A. Masarie, and R.H. Gammon. 1988. Atmospheric carbon dioxide measurements in the remote global troposphere, 1981-1984. Tellus 40B:81-115.
  • Gillette, D.A., W.D. Komhyr, L.S. Waterman, L.P. Steele, and R.H. Gammon. 1987. The NOAA/GMCC continuous CO2 record at the South Pole, 1975-1982. Journal of Geophysical Research 92(D4):4231-40.
  • Keeling, C.D. 1984. Atmospheric and oceanographic measurements needed for establishment of a data base for carbon dioxide from fossil fuels. In The Potential Effects of Carbon Dioxide-Induced Climatic Changes in Alaska. (Miscellaneous, etc.). The Proceedings of a Conference. Fairbanks, Alaska, April 7-8, 1982. School of Agriculture and Land Resources Management, University of Alaska, Fairbanks.
  • Keeling, C.D., R.B. Bacastow, A.E. Bainbridge, C.A. Ekdahl, Jr., P.R. Guenther, L.S. Waterman, and J.F.S. Chin. 1976. Atmospheric carbon dioxide variations at Mauna Loa Observatory, Hawaii. Tellus 28(6):538-51.
  • Keeling, C.D., R.B. Bacastow, A.F. Carter, S.C. Piper, T.P. Whorf, M. Heimann, W.G. Mook, and H. Roeloffzen. 1989. A three-dimensional model of atmospheric CO2 transport based on observed winds: 1. Analysis of observational data. In D.H. Peterson (ed.), Aspects of Climate Variability in the Pacific and the Western Americas. Geophysical Monograph 55:165-235.
  • Keeling, C.D., P.R. Guenther, G. Emanuele III, A. Bollenbacher, and D.J. Moss. 2002. Scripps Reference Gas Calibration System for Carbon Dioxide-in-Nitrogen and Carbon Dioxide-in-Air Standards: Revision of 1999 (with Addendum). SIO Reference Series No. 01-11.
  • Keeling, C.D., S.C. Piper, R.B. Bacastow, M. Wahlen, T.P. Whorf, M. Heimann, and H.A. Meijer. 2005. Atmospheric CO2 and 13CO2 exchange with the terrestrial biosphere and oceans from 1978 to 2000: Observations and carbon cycle implications. In J.R. Ehleringer, T.E. Cerling, and M.D. Dearing (eds.), A History of Atmospheric CO2 and its effects on Plants, Animals, and Ecosystems, pages 83-113, Springer Verlag, New York.

CITE AS: Keeling, R.F., S.C. Piper, A.F. Bollenbacher and J.S. Walker. 2008. Atmospheric CO2 records from sites in the SIO air sampling network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.