High-resolution carbon dioxide concentration record 650,000–800,000 years before present

• Published in: Nature 2008-05, Vol.453 (7193), p.379-382
• Main Authors: Lüthi, Dieter, Le Floch, Martine, Bereiter, Bernhard, Blunier, Thomas, Barnola, Jean-Marc, Siegenthaler, Urs, Raynaud, Dominique, Jouzel, Jean, Fischer, Hubertus, Kawamura, Kenji, Stocker, Thomas F.
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Carbon sequestration; Chemical properties; Climate; Cores; Earth Sciences; Earth, ocean, space; Environmental aspects; Exact sciences and technology; Glaciology; Humanities and Social Sciences; Ice; Ice cores; letter; Marine; Marine and continental quaternary; Measurement; multidisciplinary; Quaternary; Science; Science (multidisciplinary); Sciences of the Universe; Surficial geology
• ISSN: 0028-0836; 1476-4687; 1476-4679
• DOI: 10.1038/nature06949

Cover caption The air bubbles trapped in the Antarctic Vostok and EPICA Dome C ice cores provide composite records of levels of atmospheric carbon dioxide and methane covering the past 650,000 years. Now the record of atmospheric carbon dioxide and methane concentrations has been extended by two more complete glacial cycles to 800,000 years ago. The new data are from the lowest 200 metres of the Dome C core. This ice core went down to just a few metres above bedrock at a depth of 3,260 metres. Two papers report analyses of this deep ice, including the lowest carbon dioxide concentration so far measured in an ice core. Atmospheric carbon dioxide is strongly correlated with Antarctic temperature throughout the eight glacial cycles, but with significantly lower concentrations between 650,000 and 750,000 years before present. The cover shows a strip of ice core from an Antarctic ice core from Berkner Island, this slice from a depth of 120 metres. Photo by Chris Gilbert, British Antarctic Survey. Elsewhere in this issue, we move from climates past to future plans for climate prediction. Changes in past atmospheric carbon dioxide concentrations can be determined by measuring the composition of air trapped in ice cores from Antarctica. So far, the Antarctic Vostok and EPICA Dome C ice cores have provided a composite record of atmospheric carbon dioxide levels over the past 650,000 years 1 , 2 , 3 , 4 . Here we present results of the lowest 200 m of the Dome C ice core, extending the record of atmospheric carbon dioxide concentration by two complete glacial cycles to 800,000 yr before present. From previously published data 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 and the present work, we find that atmospheric carbon dioxide is strongly correlated with Antarctic temperature throughout eight glacial cycles but with significantly lower concentrations between 650,000 and 750,000 yr before present. Carbon dioxide levels are below 180 parts per million by volume (p.p.m.v.) for a period of 3,000 yr during Marine Isotope Stage 16, possibly reflecting more pronounced oceanic carbon storage. We report the lowest carbon dioxide concentration measured in an ice core, which extends the pre-industrial range of carbon dioxide concentrations during the late Quaternary by about 10 p.p.m.v. to 172–300 p.p.m.v.