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 CO 2 concentrations and their temporal variations. Earlier measurements have shown that the atmospheric CO 2 concentration was significantly lower during the late Wisconsin stage and that the change from low to high CO 2 concentration occurred in a relatively short time period. We measured the CO 2 concentration 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 CO 2 concentration which are correlated with δ 18 O values of the ice samples. A probable explanation of the results is that corresponding changes of the atmospheric CO 2 concentration occurred during that glacial period. These changes could have had a significant influence on the climate. Possible reasons for the variations of the atmospheric CO 2 concentration are discussed.