Dynamics of the Greenland Ice Sheet over multiple timescales

• Main Author: Kjeldsen, Kristian Kjellerup
• Format: Book
• Language: English
• Published: Natural History Museum of Denmark, Faculty of Science, University of Copenhagen 2013
• Subjects: Greenland; Ice Sheet
• Online Access: https://curis.ku.dk/portal/da/publications/dynamics-of-the-greenland-ice-sheet-over-multiple-timescales(04ee0af8-b6f1-4fe8-b7da-a11757be1f66).html; https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122982114205763

Since the 1990s mass loss of the Greenland Ice Sheet has accelerated substantially increasing its contribution to global sea level rise, especially during the past decade. Even though the current global sea level budget is well understood, providing better estimates of the mass loss is essential to further constrain the individual components of the current budget, and in conjunction with longer records, it is important to provide a trustworthy basis for future projections. In this thesis, using airborne- and satellite derived data combined with terrestrial and marine observations, the dynamic behavior of the Greenland Ice Sheet on multiple timescales is investigated. These range from annual/decadal scale variations of ice surface heights and cyclic drainage patterns of ice-dammed lakes to long-term response of the ice sheet margin during the past 300,000 years. The results presented here show that the ice margin of the Greenland Ice Sheet responds highly dynamic and variable to climate change and oceanic forcing, with behavior additionally being governed by regional/local settings, e.g. topographical settings such as low-lying/mountainous areas and the presence or absence of deep fjords or shelf/crossshelf troughs. Warming of ocean temperatures is suggested as being a main driver for periodic dynamic ice loss events in northwest Greenland while cooling of ocean temperatures around southern Greenland, in conjunction with increased snow accumulation, is found to drive a rapid readvance of glaciers in response to the onset of the Little Ice Age. Furthermore this thesis shows that the thinning pattern of the last decade in southern Greenland compares well with that of the entire 20th century, thus the present sensitivity distribution will arguably hold for future ice sheet mass loss until marine outlet glaciers become grounded and also assuming a similar warming pattern. This thesis implies that in order to investigate the response of the Greenland Ice Sheet to future climate change much is to be gained by merging and incorporating data from both marine and terrestrial geology, combined with air- and satellite-borne data and oceanographic observations.