Atmospheric CO2 content in the past deduced from ice core analyses

• Published in: Annals of Glaciology
• Main Authors: Oeschger, H., Stauffer, B., Neftel, A., Schwander, J., Zumbrunn, R.
• Format: Conference Object
• Language: English
• Published: International Glaciological Society 1982
• Subjects: 530 Physics; Byrd; Byrd Station; Annals of Glaciology; ice core
• Online Access: https://boris.unibe.ch/158770/1/oeschger82ag.pdf; https://boris.unibe.ch/158770/

Probably the only direct way to reconstruct historic atmospheric CO2/air ratios is by measuring the air occluded in ice samples. For such studies, ice samples from very cold regions have an advantage in that the snow and ice probably never had been in contact with liquid water, which interacts with trapped atmospheric CO2. However, even ice samples from very cold regions may have additional CO2, which could have been enclosed during the formation of precipitation, adsorbed at the surface of snow and firn grains, or produced in the ice by chemical reactions on impurities. The gas in ice samples from Camp Cenand Byrd station was extracted both by a vacuum-melting and by a mechanical crushing procedure and the CO2 abundance measured by two different analytical methods. N2/O2/Ar ratios were also measured. The shift to lower CO2 concentration in both cores at a certain depth found previously is confirmed. Changes in the atmospheric CO2 concentration at the corresponding time, about the end of the last glaciation, is the probable explanation of our CO2 results.