Greenland - 1 Flashcards
Define ‘glacier’:
A body of ice formed on land, commonly confined to a valley, and in motion.
Define ‘ice sheet’.
Describe where ‘ice sheets’ typically form.
Masses of ice that bury large tracts of land beneath them.
High-latitude regions, that have very cold, long harsh winters and short summers.
Briefly describe the movement of a glacier.
Ice and snow accumulates and flows downhill under its own weight to a point called the ‘terminus’, from which meltwater flows.
Define ‘ablation’.
Describe where ablation occurs, and the effects of ablation on the glacier.
The removal of snow and ice from a glacier by melting or evaporation.
At some point along the glacier the ice stops accumulating and begins to melt. In this zone of ablation, the colour of the ice changes from bright white to a grey colour.
Briefly describe the last ‘glacial maximum’.
State why large climate changes (as such) may have occurred.
The last glacial maximum occurred 18,000 – 20,000 years ago. During this time 30% of the Earth was covered by ice, the Earth’s average temperatures were 4C lower whilst the sea level was 100m lower.
These climate changes have been caused by a range of natural processes; volcanic activity, changes in atmospheric gas levels, ocean current changes and sun spot activity.
State the role and interconnection of human activities in causing melting glaciers and ice sheets:
The creation and distribution of cryoconite is both a result of human activities and natural processes. Cryoconite, starts off as an airborne sediment comprised of dust, from East Asian deserts, particulate matter, from volcanic eruptions, and ash, from European coal fired power plants. As the mineral is near black, when it settles on the ice it decreases the albedo of the ice sheet’s surface, thus absorbs more heat energy and melts the underlying ice over time.
