Can glaciers downsize?

Surveying Falljökull

View of Falljökull, south east Iceland

Ongoing research at the BGS Glacier Observatory in southeast Iceland shows that the Falljökull glacier has been undergoing a dramatic period of retreat since the early 1990s. This retreat rate has increased sharply since 2005/06, and has been accompanied by changes in glacier behaviour from season to season. Falljökull no longer advances during winter, but continues to melt and retreat all year round. Using a variety of methods — including radar imaging of the glacier's internal structure, terrestrial LiDAR to create detailed 3D models of the surface, permanent GPS on the ice to show glacier velocity, and highly detailed structural analysis of the glaciers faults and thrusts — the BGS team have identified dramatic changes in the glacier's structure which have only occurred over the last five years.

The new findings published online and open access in the AGU Journal of Geophysical Research reveal that Falljökull has abandoned its lower portion, which is now virtually stagnant, whilst the upper portion of the glacier has continued to flow over the lower section. Importantly, the surface of the glacier shows a characteristic bulge, just above a thrust, where the upper ice is forcing its way over the lower part of the glacier. The team suggest that this process is likely to occur elsewhere around the world such as the Himalaya, Andes, Alps and Cascades, where relatively steep, fast-flowing glaciers are struggling to respond to significant changes in their mass balance.


For more information contact Dr Emrys Phillips or Dr Jez Everest.