CO2 record in the byrd ice core 50,000 - 5,000 years BP

The analysis of air in polar ice cores revealed 30% lower CO2 values during glacial periods than during interglacial periods. At present this is confirmed by results from six different ice cores, two from Greenland and four from Antarctica (1–5). In all cores the CO2 change coincides with the change in the isotopic composition of the ice, expressed as either the δ18O or δD ratio; both are indicators for the mean annual surface temperature6. To investigate the relationship between atmospheric CO2 concentration changes with changes in climate, the atmospheric CO2 concentration during and at the end of the last glaciation has to be known in detail. To achieve this, we have studied a great number of samples from the deep ice core from Byrd station, Westantarctica, drilled in 1968. These measurements allow us to reconstruct the atmospheric CO02 concentration in the time period 50,000–15,000 yr bp in great detail.