Atmospheric Carbon Dioxide Record from the South Pole
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.
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.
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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.