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Ice-ocean interactions during Heinrich events in the Labrador Sea

The IceLab Project aims to determine the role of sea ice in past events of ice sheet collapse. Specifically, IceLab will investigate North Atlantic sea-ice dynamics across Heinrich events of the last glacial period, with focus on the Labrador Sea. 

Northern hemisphere ice sheets are particularly vulnerable to climate change as the Arctic is warming twice as fast as the rest of the planet. Scenarios of future ice sheet stability, however, are associated with significant uncertainty, due to a lack of understanding of the relevant internal climate feedbacks. These processes involve ocean-ice sheet interactions and the effects of sea ice on the terrestrial cryosphere. With increased societal concerns over rising sea levels, it is more than ever important to understand the implications of climate change for ice sheet stability. The key lies in understanding the response of past ice sheets to climate change.

Prominent episodes of past ice-sheet collapse are so-called Heinrich events during the last glacial period, originating in Hudson Strait. While modelling studies have long hinted at the importance of sea ice in the Labrador Sea for subsurface warming and ocean induced melting during Heinrich events, this has not been shown using proxy methods. IceLab will investigate the links and feedbacks of sea ice, ocean circulation, subsurface warming, and ice-sheet collapse in the Labrador Sea to determine the role of the coupled cryosphere-ocean system for ice sheet stability. Additionally, the effect of enhanced freshwater discharge on the system will be documented and a spatial-temporal map of North Atlantic sea ice dynamics across Heinrich events will be constructed. The new records will provide important clues with respect to a potential oceanic trigger of Hudson Strait iceberg surges during Heinrich events as well as advancing our understanding of the coupled cryosphere-ocean system, vital to accurately predict mass loss from the Greenland ice sheet in the future.

The work will entail an integrated approach of organic and inorganic geochemistry, using sea-ice biomarkers, foraminiferal isotopes, and foraminiferal trace metals (i.e. Mg/Ca) in combination with state-of-the-art dating and correlation techniques. The project will be conducted in collaboration with several research groups both at Aarhus University and abroad. 

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No [882893].