Observations of Greenland Ice Sheet mass loss over the past 2ka

This study aims to contribute data, that will improve understanding on the role of Greenland ice sheet melt in modulating midlatitude climate. A great hamper to our understanding of the influence from Greenland ice sheet melt on European climate variability comes from the lack of high-resolution observations of dynamic mass loss from the from Greenland Ice Sheet extending beyond the instrumental time scale. Building on a large repository of sediment cores taken from fjords by some of Greenlands largest marine terminating glaciers, we aim to reconstruct multi-decadal to centennial scale changes in the iceberg production (solid ice mass loss) over the past 2ka. The IRD proxy method has conventionally been used in deep sea cores to elucidate major instability events of glacial ice sheets but has shown potential as a glacier proxy through the correspondence of the 20th century IRD records with historical and instrumental records of glacier margin positions of Sermeq Kujalleq and Upernavik Glacier in West Greenland, and Helheim and Kangerlussuaq Glaciers in Southeast Greenland. Here we show reconstructions of dynamic mass loss from from Sermeq Kujalleq and Helheim Glacier over the past 2ka. The data indicate marked melt variability at the multidecadal to centennial time scales from West Greenland during the Roman Warm Period, whereas SE Greenland Glaciers may have been buffered by sea ice at this time.