|Title:||Temperature Reconstruction at WAIS Divide for the Last 1000 years, from Noble Gas Isotopes and Borehole Temperature|
|Author:||Orsi, A.J. and Severinghaus, J.P.|
|Periodical:||American Geophysical Union, Fall Meeting 2012, abstract #PP12B-02|
West Antarctica is warming, but it is not clear yet whether it is abnormal, in the context of natural background variability. The amplitude of natural climate variability on multi-decadal timescales remains poorly quantified, but it is essential to our understanding of the significance of the warming of the last 50 years. Here, we present a 1000-year temperature record at WAIS Divide, reconstructed from noble gas isotopes from the ice core, and borehole temperature measurements. Borehole temperature provides an absolute estimate of long-term trends, while noble gases track decadal to centennial scale changes. This method provides a temperature reconstruction that is independent of the water isotope of the ice, and allows us to improve our understanding of water isotopes as a temperature proxy at this site. We found that the "Little Ice Age" cold period of 1400-1800 was 0.52°C colder than the last century, and that 50 to 100 year variability is on the order of 0.5 to 1°C.