Ice cap and glacier

Glaciers are permanent or near-permanent ice masses, created by the compaction of the snow accumulated in cold climates. These deposits, when they are under pressure, behave like a viscous liquid. So, a glacier is a mobile element, because of its ability to slowly flow along a slope under the effect of gravity. Different types of glacier exist. Characteristic for the arctic regions, ice sheets and ice caps are dome-like ice masses unconstrained by topography. More characteristic of the large mountain ranges, but also present in the arctic regions, most glaciers are constrained by topography. This is the case for cirque glaciers, valley glaciers, mountain glaciers and piedmont glaciers. The smallest form of glacier is derived from snow-drifting, avalanches, or ice deposition in cold-bottom karst dolines. Called glacierets, these small ice masses may have an existence limited to a few years. They are especially sensitive to global warming of the climate. Climate change may cause variations in both temperature and snowfall, causing changes in the surface mass balance. Due to the extreme conditions of this habitat, especially at low temperatures, very few organisms occur in this environment, which could almost be considered sterile. Only some unicellular algae occasionally grow on the melting snow cover of glaciers during summer. These ice formations are found in high altitude or high latitude. In Europe, they occur only in the summit region of the Alps, the Pyrenees, the Scandes, and in the arctic regions.

Indicators of good quality:

• Long-term balance between accumulation of ice and melting (crucial for sustainable surviving of glaciers), usually expressed as “mass balance” or “surface mass balance” (SMB) and in this way used as a sensitive climate indicator for glaciers.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats