Atmospheric Carbon Dioxide Record from the South Pole

Graphics    Digital Data

Investigators

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

1957-2007

Methods

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.

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

Trends

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.

References

• 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.