Present Day Distribution (AQA A Level Geography)

Global Distribution of Glaciers

• Present day distribution of cold environments can be divided into polar, glacial, alpine and periglacial areas

• Polar - considered areas of permanent ice within the northern and southern extremes of the Antarctic and Arctic regions

• Therefore, found in areas of high latitude, with long winters and short summers, with high levels of storms and cold winds

  • Arctic polar environment can be defined either by the Arctic circle at 66° N or by the July isotherm of 10° C

    • Isotherms are areas of the same temperature

    • July is the hottest month and areas north of this line have an average of 10°C or below

    • Winter sea ice is shrinking

  • The Antarctic is much colder than the Arctic, with strong westerly winds, cold oceans and a large landmass

  • Winter sea ice is increasing 

  • Defined by the 10°C January isotherm (January is the hottest month in the southern hemisphere)

• Other examples include Greenland and northern Canada

• Alpine 

  • Found at any latitude but at high altitudes of over 3000m, where snow and ice remain throughout the year at higher altitudes, and has a cooler climate and seasonal coverage of snow at lower altitudes

  • Landscape includes ice caps, mountain glaciers and tundra, developed over glacial and interglacial periods

  • Tectonic uplift and rapid erosion by water and ice have created well-developed glacial landforms

  • Examples include the Himalayan and Tibetan mountain ranges in Asia, the Rockies and the Andes in the Americas, and the New Zealand Alps

• Glacial

  • Found at higher latitudes and altitudes, with high levels of precipitation, at the edges of polar ice sheets and alpine glaciers 

  • Ice remains throughout the year

  • Examples include the Andes, Himalayas and Franz Josef Glacier, NZ

• Periglacial (tundra)

  • Located at the fringes of permanent glaciated areas, either at high altitude alpine regions or high latitude polar regions and accounts for a third of the Earth's surface

  • Characterised by permafrost (large sections of permanently frozen ground) and an ‘active layer’ of seasonal thawing and re-freezing surface; up to 5 meters in depth