Summary

In this session, we have explored how glaciers are formed and defined some of the terms used in the study of glaciers. Glacier mass balance is a key concept in glaciology, and is defined as the difference between the mass gained (accumulation) and the mass lost (ablation) by a glacier over a year. Glaciers generally gain mass by snowfall and lose mass by melting and/or iceberg calving.

Because of this equation, glaciers are constantly fluctuating in size. During glacial periods (‘ice ages’), glacier ice covered up to 30% of the earth’s surface including most of Britain. It has long been thought that the last glaciers in Britain were about 11, 000 years ago, although recent studies suggest that there may have been glaciers in the Cairngorms as recently as 400 years ago.