4. Greenland Ice Shelves and Ice Tongues

This chapter focuses on a review of the glaciers on north and northeast Greenland that terminate in fiords with long glacier tongues and floating, ice-shelf-like margins. There is some debate as to whether these glacier tongues can be classified as a traditional ice shelf, so the relevant literature and physical properties are reviewed. There exists a difference between: (1) Floating glaciers in northern Greenland (>77°N) which experience bottom melting as their dominant ablation mechanism and calve relatively thin, but large (km-sized) tabular icebergs (‘ice islands’), and (2) Grounded glaciers further south (<77°N), where iceberg calving provides the dominant ablation mechanism. The relatively smaller iceberg discharge in northern Greenland is closely related to the occurrence of extended floating glacier sections, allowing bottom melting estimated at up to 10 m year⁻¹ for locations such as Petermann Glacier. A case study is described of the physical characteristics and historical changes of Nioghalvfjerdsfjorden Glacier, NE Greenland, based on field and remote sensing studies.