ITASE-2002-4 Antarctic Ice Core 400 Year Oxygen Isotope Data Steig, E.J. Steig, E.J. earth science/paleoclimate/ice core (ITASE 02-4>LATITUDE -86.5>LONGITUDE -107.99) Changes in atmospheric circulation over the past five decades have enhanced the wind-driven inflow of warm ocean water onto the Antarctic continental shelf, where it melts ice shelves from below. Atmospheric circulation changes have also caused rapid warming over the West Antarctic Ice Sheet, and contributed to declining sea-ice cover in the adjacent Amundsen-Bellingshausen seas. It is unknown whether these changes are part of a longer-term trend. Here, we use water-isotope (d18O) data from an array of ice-core records to place recent West Antarctic climate changes in the context of the past two millennia. We find that the d18O of West Antarctic precipitation has increased significantly in the past 50 years, in parallel with the trend in temperature, and was probably more elevated during the 1990s than at any other time during the past 200 years. However, d18O anomalies comparable to those of recent decades occur about 1% of the time over the past 2,000 years. General circulation model simulations suggest that recent trends in d18O and climate in West Antarctica cannot be distinguished from decadal variability that originates in the tropics. We conclude that the uncertain trajectory of tropical climate variability represents a significant source of uncertainty in projections of West Antarctic climate and ice-sheet change. STUDY NOTES: Antarctic ice core ITASE-2002-4 sub-annual oxygen isotope (d18O) data for the past 400 years. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Steig, E.J. 2017-05-19 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/22520 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/itase2002d18o.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/itase2002d18o.txt English https://www.ncdc.noaa.gov/paleo/study/22520 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/itase2002d18o.txt Eric J. Steig, Qinghua Ding, James W.C. White, Marcel Küttel, Summer B. Rupper, Thomas A. Neumann, Peter D. Neff, Ailie J.E. Gallant, Paul A. Mayewski, Kendrick C. Taylor, Georg Hoffmann, Daniel A. Dixon, Spruce W. Schoenemann, Bradley R. Markle, Tyler J. Fudge, David P. Schneider, Andrew J. Schauer, Rebecca P. Teel, Bruce H. Vaughn, Landon Burgener, Jessica Williams, Elena Korotkikh2013Recent climate and ice-sheet changes in West Antarctica compared with the past 2,000 yearsNature Geoscience65372-37510.1038/ngeo1778http://www.nature.com/ngeo/journal/v6/n5/full/ngeo1778.html David P. Schneider and Eric J. Steig 2008Ice cores record significant 1940s Antarctic warmth related to tropical climate variabilityProceedings of the National Academy of Sciences10534 12154-1215810.1073/PNAS.0803627105http://www.pnas.org/content/105/34/12154 START YEAR: 1593 AD * END YEAR: 2002 AD -107.99 -86.5 -107.99 -86.5