Climate, Elevation, and Tropical Pacific Teleconnections: The Siple Dome Ice Stable Isotopes Reveal a Complex West Antarctic Climate History

To date, only 2 deep ice cores have been recovered from West Antarctica: Byrd and Siple Dome. Taken together, the isotope records from these 2 sites allow us to begin to disentangle the climate and elevation histories of West Antarctica over the last 100,000 years. Comparing the climate history deduced from Byrd and Siple Dome with similar records from East Antarctica reveals significant spatial heterogeneity in climate response across Antarctica throughout the last climate cycle. This spatial heterogeneity is particularly pronounced during the late Holocene, when Byrd and Siple Dome suggest that West Antarctica is warming, possibly due to the influence of low-latitude Pacific climate over the Ross Sea region (analogous to modern teleconnections). The Siple Dome deuterium excess record appears to share significant variance with a variety of climate proxies for the last ~100,000 years, such as Mg/Ca records from the tropical and mid-latitude Pacific, and other ice core-derived records that are thought to have tropical significance, such as the global methane record. Because the Siple Dome ice core site receives the majority of its moisture from the Pacific Ocean, this record suggests a persistent teleconnection between the high-latitude Pacific-West Antarctic region and the low-latitude Pacific. Intriguingly, the Siple Dome deuterium excess record suggests that evaporative conditions in the high-latitude Pacific during the last glacial period have covaried with tropical/Northern Hemisphere climate, rather than with Antarctic climate.