title: Carbon isotope constraints on the deglacial CO₂ rise from ice cores.
abstract: The stable carbon isotope ratio of atmospheric CO(2) (δ(13)C(atm)) is a key parameter in deciphering past carbon cycle changes. Here we present δ(13)C(atm) data for the past 24,000 years derived from three independent records from two Antarctic ice cores. We conclude that a pronounced 0.3 per mil decrease in δ(13)C(atm) during the early deglaciation can be best explained by upwelling of old, carbon-enriched waters in the Southern Ocean. Later in the deglaciation, regrowth of the terrestrial biosphere, changes in sea surface temperature, and ocean circulation governed the δ(13)C(atm) evolution. During the Last Glacial Maximum, δ(13)C(atm) and atmospheric CO(2) concentration were essentially constant, which suggests that the carbon cycle was in dynamic equilibrium and that the net transfer of carbon to the deep ocean had occurred before then.
authors.affiliation: Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern, Switzerland. schmitt@climate.unibe.ch
authors.forename: Jochen
authors.initials: J
authors.lastname: Schmitt
authors.forename: Robert
authors.initials: R
authors.lastname: Schneider
authors.forename: Joachim
authors.initials: J
authors.lastname: Elsig
authors.forename: Daiana
authors.initials: D
authors.lastname: Leuenberger
authors.forename: Anna
authors.initials: A
authors.lastname: Lourantou
authors.forename: Jérôme
authors.initials: J
authors.lastname: Chappellaz
authors.forename: Peter
authors.initials: P
authors.lastname: Köhler
authors.forename: Fortunat
authors.initials: F
authors.lastname: Joos
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Stocker
authors.forename: Markus
authors.initials: M
authors.lastname: Leuenberger
authors.forename: Hubertus
authors.initials: H
authors.lastname: Fischer
mesh_terms: D000864:Antarctic Regions; D001272:Atmosphere; D057486:Carbon Cycle; D002245:Carbon Dioxide; D002247:Carbon Isotopes; D057231:Climate Change; D046448:Ice Cover; D009792:Oceans and Seas; D012623:Seawater; D013696:Temperature; D013995:Time; D014872:Water Movements
chemical_list: D002247:Carbon Isotopes; D002245:Carbon Dioxide