Last Glacial Maximum CO2 and δ13C successfully reconciled

Bouttes, N., Paillard, D., Roche, D. M., Brovkin, V. and Bopp, L. (2011) Last Glacial Maximum CO2 and δ13C successfully reconciled. Geophysical Research Letters. L02705. ISSN 0094-8276 doi: 10.1029/2010GL044499

Abstract/Summary

During the Last Glacial Maximum (LGM, ∼21,000 years ago) the cold climate was strongly tied to low atmospheric CO2 concentration (∼190 ppm). Although it is generally assumed that this low CO2 was due to an expansion of the oceanic carbon reservoir, simulating the glacial level has remained a challenge especially with the additional δ13C constraint. Indeed the LGM carbon cycle was also characterized by a modern-like δ13C in the atmosphere and a higher surface to deep Atlantic δ13C gradient indicating probable changes in the thermohaline circulation. Here we show with a model of intermediate complexity, that adding three oceanic mechanisms: brine induced stratification, stratification-dependant diffusion and iron fertilization to the standard glacial simulation (which includes sea level drop, temperature change, carbonate compensation and terrestrial carbon release) decreases CO2 down to the glacial value of ∼190 ppm and simultaneously matches glacial atmospheric and oceanic δ13C inferred from proxy data. LGM CO2 and δ13C can at last be successfully reconciled.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/26279
Identification Number/DOI	10.1029/2010GL044499
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology Science > School of Mathematical, Physical and Computational Sciences > NCAS
Publisher	American Geophysical Union
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