West Antarctic Ice Sheet (WAIS) Ice Core WDC-05A 1000 Year CO2 Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: Please cite original reference when using these data, plus the data file URL and date accessed. NAME OF DATA SET: West Antarctic Ice Sheet (WAIS) Ice Core WDC-05A 1000 Year CO2 Data LAST UPDATE: 5/2012 (Original receipt by WDC Paleo) CONTRIBUTORS: Ahn, J., E.J. Brook, L. Mitchell, J. Rosen, J.R. McConnell, K. Taylor, D. Etheridge, and M. Rubino. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2012-070 WDC PALEO CONTRIBUTION SERIES CITATION: Ahn, J., et al. 2012. West Antarctic Ice Sheet (WAIS) Ice Core WDC-05A 1000 Year CO2 Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2012-070. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Ahn, J., E.J. Brook, L. Mitchell, J. Rosen, J.R. McConnell, K. Taylor, D. Etheridge, and M. Rubino. 2012. Atmospheric CO2 over the last 1000 years: A high-resolution record from the West Antarctic Ice Sheet (WAIS) Divide ice core. Global Biogeochem. Cycles, 26, 2, GB2027, doi:10.1029/2011GB004247 ABSTRACT: We report a decadally resolved record of atmospheric CO2 concentration for the last 1000 years, obtained from the West Antarctic Ice Sheet (WAIS) Divide shallow ice core. The most prominent feature of the pre-industrial period is a rapid ~7 ppm decrease of CO2 in a span of ~20-50 years at ~1600 A.D. This observation confirms the timing of an abrupt atmospheric CO2 decrease of ~10 ppm observed for that time period in the Law Dome ice core CO2 records, but the true magnitude of the decrease remains unclear. Atmospheric CO2 variations over the time period 1000-1800 A.D. are statistically correlated with northern hemispheric climate and tropical Indo-Pacific sea surface temperature. However, the exact relationship between CO2 and climate remains elusive due to regional climate variations and/or uneven geographical data density of paleoclimate records. We observe small differences of 0 ~ 2% (0 ~ 6 ppm) among the high-precision CO2 records from the Law Dome, EPICA Dronning Maud Land and WAIS Divide Antarctic ice cores. However, those records share common trends of CO2 change on centennial to multicentennial time scales, and clearly show that atmospheric CO2 has been increasing above preindustrial levels since ~1850 A.D. GEOGRAPHIC REGION: Antarctica PERIOD OF RECORD: 0 - 1000 YrBP FUNDING SOURCES: US National Science Foundation (OPP-0739766, OPP 0538427, OPP 0739780) Gary Comer Science and Education Foundation, Korea Polar Research Institution (KOPRI) grant PE 11090, Basic Science Research Program of the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (2011-0025242). DATA FILE URLS: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2012co2.txt ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2012co2.xls DESCRIPTION: Atmospheric CO2 data from the West Antarctic Ice Sheet (WAIS) Divide shallow core WDC05A. We measured samples from 109 depth intervals of the WDC05A core. Each depth interval was usually less than 10 cm and 3 ~ 6 replicates (4 on average) were analyzed for each depth interval. The average standard deviation of replicates from the same depth interval was 1.6 ppm. WAIS Divide Core WDC-05A: 79.463ºS, 112.125ºW, 1759 m elev. DATA: Ahn et al. 2012 Core WDC-05A CO2 Data *The CO2 mixing ratios were corrected for experimental offset and gravitational fractionation. **The uncertainty was estimated from the standard deviation of the mean for several replicate ice samples. MeanDepth Year MeanCO2* Uncertainty #ofReplicate (m) (A.D.) (ppm) (ppm) Ice Samples 78.973 1939.9 311.6 1.6 6 80.095 1935.4 307.1 0.2 12 80.595 1933.2 306.5 1.3 5 82.588 1925.0 303.9 0.3 6 84.640 1916.4 298.8 1.2 4 86.385 1909.1 300.7 1.4 6 88.355 1900.7 295.9 0.6 5 90.153 1892.0 294.0 0.8 3 92.120 1882.8 292.1 0.3 2 94.671 1871.5 289.8 0.3 3 97.150 1861.6 288.3 1.5 3 98.394 1857.6 286.7 0.3 3 100.650 1848.4 286.9 1.1 3 102.702 1839.0 285.3 0.7 3 105.220 1828.4 285.9 0.2 3 106.328 1824.0 286.0 0.6 3 109.101 1812.0 284.4 0.3 5 110.575 1805.8 284.4 0.7 6 110.880 1805.0 282.6 0.7 4 113.160 1796.2 283.7 1.2 6 114.855 1786.8 281.7 0.6 3 115.100 1785.7 284.2 0.9 3 116.900 1777.6 281.8 0.3 3 118.740 1770.0 280.0 1.3 5 121.195 1759.0 281.7 0.6 4 123.220 1750.1 280.1 0.6 3 124.770 1743.2 280.6 1.4 3 126.795 1734.6 278.7 1.2 3 128.720 1726.2 281.4 0.4 4 130.850 1716.4 278.9 0.6 3 132.808 1707.1 279.0 1.8 7 134.695 1698.8 279.5 0.6 4 136.310 1693.0 278.9 0.5 4 138.878 1683.8 279.1 0.7 6 140.883 1675.2 277.7 0.5 5 142.426 1669.1 278.0 0.7 4 147.228 1644.1 279.2 0.6 4 149.073 1635.5 278.8 1.0 4 150.012 1631.5 281.3 0.5 6 152.717 1620.1 278.6 0.6 6 154.388 1613.1 282.2 0.5 9 157.129 1601.4 280.9 0.9 8 158.589 1595.5 279.9 0.7 4 160.499 1586.9 283.2 1.2 5 162.000 1580.2 283.9 0.9 3 163.476 1574.3 286.4 0.9 5 166.126 1564.1 285.5 0.6 5 168.623 1553.4 285.8 0.5 5 170.022 1547.5 283.9 1.5 6 172.690 1536.1 286.3 0.2 4 174.021 1530.4 284.7 0.4 4 176.355 1519.7 285.5 0.9 4 177.538 1513.8 285.3 0.8 4 180.373 1500.4 285.3 0.1 3 182.286 1491.5 282.2 0.5 10 184.430 1482.0 282.7 0.4 3 186.510 1472.1 283.3 0.7 3 187.745 1467.2 283.8 0.5 3 190.062 1456.9 281.1 0.3 4 192.474 1447.3 283.5 0.4 5 194.375 1439.4 281.9 1.7 4 196.528 1428.1 282.5 0.5 3 198.150 1421.3 284.6 0.3 4 200.148 1412.8 282.5 0.1 4 201.780 1406.5 284.8 1.4 4 204.990 1391.3 285.2 0.6 6 207.166 1381.4 283.5 0.6 4 207.825 1378.7 284.1 0.9 3 209.798 1369.2 285.3 0.5 3 212.656 1356.2 284.7 1.3 5 214.243 1348.3 283.7 0.7 3 216.507 1339.1 284.9 0.9 7 219.082 1329.0 284.5 0.7 8 220.999 1320.3 284.4 0.4 12 222.926 1312.0 285.4 0.3 3 224.870 1303.1 283.8 0.4 3 226.081 1297.7 284.4 1.3 3 228.310 1286.0 284.7 1.2 8 229.981 1278.9 283.7 1.3 4 232.095 1270.2 284.9 0.8 3 234.037 1261.6 286.1 1.1 3 235.770 1254.8 283.2 0.8 4 237.340 1248.4 284.3 0.8 3 240.495 1235.1 283.6 1.3 3 243.344 1224.2 286.2 1.9 9 245.020 1217.6 284.1 1.1 3 246.556 1211.9 284.2 0.6 3 248.256 1205.4 284.3 0.5 6 248.840 1203.2 287.5 1.2 6 251.708 1193.7 286.5 1.1 3 254.105 1179.5 285.1 0.8 4 256.315 1169.7 286.3 0.4 4 260.970 1150.0 287.4 1.2 4 262.425 1143.7 284.6 0.4 4 266.768 1126.3 286.1 0.6 5 269.153 1116.9 285.3 0.5 3 272.243 1103.0 286.5 1.4 4 275.252 1090.4 285.4 0.4 6 277.235 1082.5 285.4 0.6 4 278.567 1076.7 284.5 0.8 3 279.850 1072.2 283.3 0.3 3 285.196 1046.7 283.9 1.0 4 286.050 1042.6 282.1 1.2 4 286.271 1041.4 282.3 0.4 5 286.719 1039.0 280.6 1.2 3 288.830 1030.1 282.9 1.0 4 292.165 1015.9 284.0 1.4 3 295.590 1001.7 282.0 0.6 4 297.575 993.1 282.0 0.6 4