Atmospheric CO2 Concentration During the Last Glaciation

Abstract

Analyses of atmospheric air extracted from air bubbles in polar glacier ice provide a measure of past CO₂concentrations and their temporal variations. Earlier measurements have shown that the atmospheric CO₂concentration was significantly lower during the late Wisconsin stage and that the change from low to high CO₂concentration occurred in a relatively short time period.We measured the CO₂concentration of ice samples from the deep ice core recently drilled at Dye 3 (south Greenland). The core section investigated represents ice from about 40 to 30 ka BP. The air extracted from the ice samples shows large variations of CO₂concentration which are correlated with δ¹⁸O values of the ice samples. A probable explanation of the results is that corresponding changes of the atmospheric CO₂concentration occurred during that glacial period. These changes could have had a significant influence on the climate. Possible reasons for the variations of the atmospheric CO₂concentration are discussed.