Greenland glaciers outside the ice sheet

Abstract

The local glaciers surrounding the GIS constitute a significant proportion (5–10%) of the global ice masses besides ice sheets. Nevertheless, they have not yet received much attention. The actual size of local glaciers in Greenland is difficult to determine because there is a gradual transition from dynamically dependence to independence from the GIS. This interrelationship along parts of the GIS margin may have fluctuated throughout the Holocene. Many coastal local glaciers diminished or disappeared during the Holocene Climatic Optimum (8,500–6,000 BP) and reformed to have a maximal Holocene extent at the end of the Little Ice Age (1150– 1920 AD). Current mass balance measurements are in concordance with the global negative trend. Two areas with widespread surge activity exist in Greenland: the East Greenland surge cluster and the Disko-Nuussuaq surge cluster. Both clusters are mainly located on Tertiary basaltic rocks and have surge cycle periodicity of more than 100 years. The contribution from local Greenlandic glaciers to global sea-level rise derives mainly from meltwater runoff rather than marine calving, but a total contribution has not been thoroughly estimated due to the problems with the definition of local glaciers. The specific contribution of suspended sediments and solutes from glacierized areas is highest from the basaltic regions in West and East Greenland.