2007 Volume 46 Issue 2 Pages 147-164
During the last glacial period, the climate of the Northern Hemisphere underwent abrupt warming events. This millennial-scale climate change, which was discovered from Greenland ice cores, is called the Dansgaard-Oeschger (D-O) event. Further comparison of polar ice cores suggests that warming in Antarctica preceded the onset of Greenland’s warming. These climate reconstructions rely mainly on stable isotope ratios (δD and δ18O) of water in polar ice cores because the air-temperature history has been inferred from a regional correlation between water isotope ratios and surface air-temperature. However, this reconstruction technique probably underestimates the temperature change in the Greenland summit area. This underestimation of the water isotope thermometer is caused mainly by changes in the seasonality of precipitation and changes in ocean surface conditions of the vapor source. One parameter, deuterium excess, offers the potential to reconstruct ocean surface conditions of the vapor origin ; it would improve the precision of temperature reconstruction.