Sea level fall during glaciation stabilized atmospheric CO2 by enhanced volcanic degassing.

Hasenclever, Jörg, Knorr, Gregor, Rüpke, Lars H. , Köhler, Peter, Morgan, Jason, Garofalo, Kristin, Barker, Stephen, Lohmann, Gerrit and Hall, Ian R. (2017) Sea level fall during glaciation stabilized atmospheric CO2 by enhanced volcanic degassing. Open Access Nature Communications, 8 (15867). DOI 10.1038/ncomms15867.

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Abstract

Paleo-climate records and geodynamic modelling indicate the existence of complex interactions between glacial sea level changes, volcanic degassing and atmospheric CO2, which may have modulated the climate system's descent into the last ice age. Between ∼85 and 70 kyr ago, during an interval of decreasing axial tilt, the orbital component in global temperature records gradually declined, while atmospheric CO2, instead of continuing its long-term correlation with Antarctic temperature, remained relatively stable. Here, based on novel global geodynamic models and the joint interpretation of paleo-proxy data as well as biogeochemical simulations, we show that a sea level fall in this interval caused enhanced pressure-release melting in the uppermost mantle, which may have induced a surge in magma and CO2 fluxes from mid-ocean ridges and oceanic hotspot volcanoes. Our results reveal a hitherto unrecognized negative feedback between glaciation and atmospheric CO2 predominantly controlled by marine volcanism on multi-millennial timescales of ∼5,000-15,000 years.

Document Type: Article
Research affiliation: HGF-AWI
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Refereed: Yes
Open Access Journal?: Yes
Publisher: Nature Research
Projects: PACES, OCEANS, REKLIM, PalMod in-kind
Date Deposited: 20 Jul 2017 08:28
Last Modified: 18 Jun 2020 08:55
URI: https://oceanrep.geomar.de/id/eprint/38828

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