Labrador current variability over the last 2000 years

•First subdecadal-scale SSTs (alkenones) in the Labrador Sea over the last 2k.•Role of NAM index on SSTs (direct atmospheric forcing and Arctic waters gateways).•NAM/proxy SSTs correlation agrees with modern correlation map of NAO/AO vs SSTs.•Role of NAM on LIA and MCA in the Labrador Sea/Northern Gulf Stream boundary.•Implications of our findings future climate in Northeastern America.

The ice-loaded Labrador Current (LC) is an important component of the western North Atlantic circulation that influences the position and strength of the northern limb of the North Atlantic Current (NAC). This flow of cold and fresh Polar Waters originating from the Arctic has a marked impact on the North Atlantic climate, yet little is known about its variability beyond the instrumental period. In this study, we present the first sub-decadal alkenone-based 2000-year long sea-surface temperature (SST) records from the western Labrador Sea, a climatically crucial region at the boundary between the LC and the NAC. Our results show a clear link between the LC strength and the Northern Annular Mode (NAM), with a stronger NAM and a more vigorous LC during the Medieval Climate Anomaly (MCA). This suggests enhanced LC activity upon future global warming with implications for the Atlantic meridional overturning circulation (AMOC).

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