title: Carbon isotopes characterize rapid changes in atmospheric carbon dioxide during the last deglaciation.
abstract: An understanding of the mechanisms that control CO2 change during glacial-interglacial cycles remains elusive. Here we help to constrain changing sources with a high-precision, high-resolution deglacial record of the stable isotopic composition of carbon in CO2(δ(13)C-CO2) in air extracted from ice samples from Taylor Glacier, Antarctica. During the initial rise in atmospheric CO2 from 17.6 to 15.5 ka, these data demarcate a decrease in δ(13)C-CO2, likely due to a weakened oceanic biological pump. From 15.5 to 11.5 ka, the continued atmospheric CO2 rise of 40 ppm is associated with small changes in δ(13)C-CO2, consistent with a nearly equal contribution from a further weakening of the biological pump and rising ocean temperature. These two trends, related to marine sources, are punctuated at 16.3 and 12.9 ka with abrupt, century-scale perturbations in δ(13)C-CO2 that suggest rapid oxidation of organic land carbon or enhanced air-sea gas exchange in the Southern Ocean. Additional century-scale increases in atmospheric CO2 coincident with increases in atmospheric CH4 and Northern Hemisphere temperature at the onset of the Bølling (14.6-14.3 ka) and Holocene (11.6-11.4 ka) intervals are associated with small changes in δ(13)C-CO2, suggesting a combination of sources that included rising surface ocean temperature.
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331; Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom; tkb28@cam.ac.uk.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Bauska
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093;
authors.forename: Daniel
authors.initials: D
authors.lastname: Baggenstos
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331;
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Brook
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331;
authors.forename: Alan C
authors.initials: AC
authors.lastname: Mix
authors.affiliation: Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706;
authors.forename: Shaun A
authors.initials: SA
authors.lastname: Marcott
authors.affiliation: Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627;
authors.forename: Vasilii V
authors.initials: VV
authors.lastname: Petrenko
authors.affiliation: Climate and Atmosphere Center, National Institute of Water and Atmospheric Research Ltd, Wellington, New Zealand 6023.
authors.forename: Hinrich
authors.initials: H
authors.lastname: Schaefer
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093;
authors.forename: Jeffrey P
authors.identifier: http://orcid.org/0000-0001-8883-3119
authors.initials: JP
authors.lastname: Severinghaus
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331;
authors.forename: James E
authors.initials: JE
authors.lastname: Lee
keywords: atmospheric CO2; carbon cycle; ice cores; last deglaciation; paleoclimate