The transition from the last ice age to the present-day interglacial was interrupted by the Younger Dryas (YD) cold period. While many studies exist on this climate event, only few include high-resolution marine records that span the YD. In order to better understand the interactions between ocean, atmosphere and ice sheet stability during the YD, more high-resolution proxy records from the Arctic, located proximal to ice sheet outlet glaciers, are required. Here we present the first diatom-based high-resolution quantitative reconstruction of sea surface conditions from central-eastern Baffin Bay, covering the period 14.0-10.2 kyr BP. Our record reveals warmer sea surface conditions and strong interactions between the ocean and the West Greenland ice margin during the YD. These warmer conditions were caused by increased Atlantic-sourced water inflow combined with amplified seasonality. Our results emphasize the importance of the ocean for ice sheet stability under the current changing climate.

Sediment core SL 170, taken from the deepest ploughmark on the Disko Trough outer shelf in central-eastern Baffin Bay, was studied on high resolution for ocean surface conditions between 14.0 and 10.2 kyr BP. Diatom assemblages were converted to quantitative august sea surface temperatures (aSST) using a weighted-averaging partial least squares (WA-PLS) transfer function and large North Atlantic calibration dataset. Diatom assemblages and produced high-resolution record shows warmer SSTs during the Younger Dryas and these warmer conditions played a key part in the Jakobshavn Isbræ ice margin retreat.

Supplement to: Oksman, Mimmi; Weckström, Kaarina; Miettinen, Arto; Juggins, Stephen; Divine, D V; Jackson, Rebecca; Telford, Richard J; Korsgaard, Niels J; Kucera, Michal (2017): Younger Dryas ice margin retreat triggered by ocean surface warming in central-eastern Baffin Bay. Nature Communications, 8(1)