Greenland tidewater glacier advanced rapidly during era of Norse settlement

• Main Authors: Pearce, Danni M, Lea, James M, Mair, Douglas WF, Rea, Brice R, Schofield, J Edward, Kamenos, Nicholas A, Schoenrock, Kathryn M, Stachnik, Lukasz, Lewis, Bonnie, Barr, Iestyn, Mottram, Ruth
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of America 2022
• Subjects: glacier; Greenland; Ice Sheet; Tidewater
• Online Access: https://e-space.mmu.ac.uk/629535/1/Pearce%20et%20al%20Geology%20accepted%20MS.pdf

Our ability to improve prognostic modeling of the Greenland Ice Sheet relies on understanding the long-term relationships between climate and mass flux (via iceberg calving) from marine-terminating tidewater glaciers (TWGs). Observations of recent TWG behavior are widely available, but long-term records of TWG advance are currently lacking. We present glacial geomorphological, sedimentological, archaeological, and modeling data to reconstruct the ~20 km advance of Kangiata Nunaata Sermia (KNS; the largest tidewater glacier in southwest Greenland) during the first half of the past millennium. The data show that KNS advanced ~15 km during the 12th and 13th centuries CE at a rate of ~115 m a–1, contemporaneous with regional climate cooling toward the Little Ice Age and comparable to rates of TWG retreat witnessed over the past ~200 years. Presence of Norse farmsteads proximal to KNS demonstrates their resilience to climate change, manifest as a rapidly advancing TWG in a cooling climate. The results place limits on the magnitude of ice-margin advance and demonstrate TWG sensitivity to climate cooling as well as warming. These data combined with our grounding-line stability analysis provide a long-term record that validates approaches to numerical modeling aiming to link calving to climate.