Carbon Isotope Constraints on the Deglacial CO 2 Rise from Ice Cores

• DOI: 10.1126/science.1217161
• Publication Date: 2012-03-30T06:22:23Z
• Authors: Jochen Schmitt; Robert Schneider; Joachim Elsig; Daiana Leuenberger; Anna Lourantou; Jérôme Chappellaz; Peter Köhler; Fortunat Joos; Thomas F. Stocker; Markus Leuenberger; Hubertus Fischer
• Keywords: biosphere; carbon isotope; sea; deglaciation; surface temperature; 01 natural sciences; equilibrium constant; sea surface temperature; carbon cycle; stable isotope; 14. Life underwater; Southern Ocean; 0105 earth and related environmental sciences; carbon; article; carbon dioxide; 15. Life on land; sea ice; priority journal; 13. Climate action; ice core record; atmosphere; Antarctica; ice core

By the Numbers

As carbon dioxide is exchanged between the atmosphere, the oceans, and the terrestrial biosphere, its carbon isotopic composition is modified by various processes involved in its transfer between the different reservoirs. The carbon isotopic composition of the carbon dioxide contained in bubbles of air trapped in ice cores thus provides a record of the processes that regulated the composition of the atmosphere in the past. Using data from three Antarctic ice cores,

Schmitt et al.

(p. 711 , published online 29 March; see the Perspective by

Brook

) present a record of the carbon isotopic makeup of atmospheric CO 2 for the past 24,000 years. The findings reveal the dominant role of the oceans during the early part of the deglaciation and the effects of the regrowth of the terrestrial biosphere later in the deglacial transition. Before the deglaciation, during the Last Glacial Maximum, the carbon cycle was essentially at equilibrium.