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| Titel |
The role of North Atlantic Ocean circulation and biological sequestration on atmospheric CO2 uptake during the last deglaciation (CL Division Outstanding ECS Award Lecture) |
| VerfasserIn |
Francesco Muschitiello, William J. D'Andrea, Trond M. Dokken, Andreas Schmittner |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250139127
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| Publikation (Nr.) |
 EGU/EGU2017-2305.pdf |
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| Zusammenfassung |
| Understanding the impact of ocean circulation on the global atmospheric CO2 budget is of
paramount importance for anticipating the consequences of projected future changes in
Atlantic Meridional Overturning Circulation (AMOC). In particular, the efficiency of the
oceanic biological pump can impact atmospheric CO2 through changes in vertical carbon
export mediated by variations in the nutrient inventory of the North Atlantic basin. However,
the causal relationship between North Atlantic Ocean circulation, biological carbon
sequestration, and atmospheric CO2 is poorly understood. Here we present new
high-resolution planktic-benthic 14C data and biomarker records from an exceptionally
well-dated marine core from the Nordic Seas spanning the last deglaciation ( 15,000-10,000
years BP). The records document for the first time large and rapid atmospheric CO2
drawdowns and increase in plankton stocks during major North Atlantic cooling events.
Using transient climate simulations from a fully coupled climate-biosphere model, we show
that minor perturbations of the North Atlantic biological pump resulting from surface
freshening and AMOC weakening can have a major impact on the global atmospheric CO2
budget. Furthermore, our data help clarifying the timing and magnitude of the deglacial CO2
signal recorded in Antarctic ice cores. We conclude that the global CO2 budget is more
sensitive to perturbations in North Atlantic circulation than previously thought,
which has significance in the future debate of the AMOC response to anthropogenic
warming. |
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