Nature 295, 220 - 223 (21 January 1982); doi:10.1038/295220a0

Ice core sample measurements give atmospheric CO₂ content during the past 40,000 yr

A. Neftel, H. Oeschger, J. Schwander, B. Stauffer & R. Zumbrunn

Physics Institute, University of Bern, CH-3012 Bern, Switzerland

Recent measurements^1,2 on ice samples from Camp Century (Greenland, 77°10'N, 61°08'W), Byrd Station (Antarctica, 80°01'S, 110°31'W) and Dome C (74°40'S, 125°10'E) suggest that during the late part of the last glaciation the atmospheric CO₂ concentration was significantly lower than during the Holocene. Further investigation of this natural increase of the atmospheric CO₂ concentration in the past should aid our understanding of the climatic implications of the man-made CO₂ increase since the beginning of industrialization³. Here we report new and precise measurements of the CO₂ concentration of the air occluded in bubbles of ice samples from Camp Century and Byrd Station, using a new dry extraction technique. The extracted gases were analysed with an IR-laser spectrometer (IRLS). Samples from 22 different depths were analysed from each core. The samples are distributed over a depth interval corresponding approximately to the past 40,000 yr. In addition results for ice samples from selected depth horizons from a colder region (North Central, Greenland 74°37'N, 39°36'W) and from a warmer region (Dye-3, Greenland 65°11'N, 43°50'W) are given. Based on these results we estimate the trend of the atmospheric CO₂ concentration during the past 40,000 yr.

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