Atmospheric CO2 concentration and millennial-scale climate change during the last glacial period

Air bubbles which were trapped in polar ice have been analysed and the concentrations of CO2 over various periods have been calculated. Changes in the climate over many thousands of years tend to change the concentrations of CO2 in the atmosphere. However, CO2 concentrations during rapid climate changes are less certain. Research into CO2 from Greenland and Antarctic ice has been inconclusive. An accurate time scale is required to compare the data from Greenland with the Antarctic and a method has been developed which uses concentrations of atmospheric methane from both the ice samples.