The future of Narsap Sermia: Documenting the retreat of a tidewater glacier in Southwest Greenland
The behaviour of Greenland’s tidewater glaciers is crucial for the understanding of the Greenland Ice Sheet. The retreat of those marine-terminating glaciers has far-reaching implications, impacting not only the regional hydrography but also the diverse fjord ecosystems. Here, this study investigated the rapid retreat of Narsap Sermia (NS), a tidewater glacier located in Southwest Greenland. Between 1987 and 2022, the volume of ice discharged from NS increased by 45%, a rate more than double the Greenlandic mean. This destabilization led to retreat events occurring in three distinct episodes: 2004-2005, 2010-2012, and 2019-2021. The study identified that changes in subglacial hydrology were pivotal in triggering and sustaining these retreats. Drainage of ice-dammed lakes or increased meltwater resulting from heatwaves over the ice sheet suddenly increased subglacial freshwater discharge, subsequently instigating these retreat events. Once initiated, exposure to elevated ocean temperatures or retreat into a glacial trough further sustained ice loss at the terminus, eventually resulting in a collapse of the glacial front. As of the summer of 2023, Narsap Sermia is still retreating, and the study anticipates that further retreat of approximately 3 kilometers is inevitable. Subsequently, should air and ocean temperatures continue to rise, Narsap Sermia is poised to retreat further for 30 km, dramatically transitioning into a land-terminating glacier. This drastic transformation could occur in as little as 30 years, with profound consequences for local eco-hydrology and nearby communities.
Umhverfisbreytingar á norðurslóðum, Glacier dynamics, Subglacial hydrology, Fjord hydrography, Greenland
Networked Digital Library of Theses and Dissertations