A basic problem has arisen in the discussion about the role of atmospheric CO2 in the global climatic changes. This refers to the quantity of CO2 confined in frozen water (ice or snow) by adsorption, absorption or ,,chemisorption＇＇. During the determination of CO2 in the air and in the gas bubbles trapped in the Antarctic and Greenland ice cores by the IR spectroscopy, the moisture in the gas sample is frozen out. This step seems to have an effect on the CO2 values obtained. Bearing the significance of the CO2 problem in mind, the accuracy of the applied method should be evaluated.