AS Geography Cold Environments

True or False? 1. 20,000 years ago a third of the land surface of the earth was covered by snow and ice – this included parts of Britain. TRUE 2. Glaciers have the power to erode, transport and deposit material to completely change the landscape. TRUE 3. The landscape of the Lake District shows evidence of past glacial phases. TRUE. 4. Cold environments are increasingly under threat due to the development of tourism and mineral extraction. TRUE

Questions for Investigation… 1.What processes and factors give cold environments their distinctive characteristics? 2.Why are cold environments considered to be ‘fragile’? 3.What are the issues associated with the development of cold environments? 4.How can cold environments be managed to ensure sustainability? In the exam the extended essay style question will be based around questions 3 and 4.

Learning Objectives … By the end of the lesson you will be able to: 1.Describe the location of cold environments in the world. 2.Identify and explain the climatic characteristics of these areas. 3.Use this information to establish the influence glaciation has on Britain's natural landscapes.

Where are cold environments? Cold environments occur in two types of location: High latitudes High altitude – mountainous areas. The most extreme cold environments have a permanent cover of ice and snow. Virtually the whole of Antarctica and most of Greenland are smothered by ice sheets, in places 2-3km thick. Over the Greenland ice sheet, temperatures average -33 degrees in winter.

Question time… Why is Antarctica so cold? This is explain by Antarctica’s high latitude: only the Antarctic peninsular lies north of the Antarctic Circle.

Question time … Why is Greenland so cold? The southern tip of Greenland is the same latitude as northern Scotland. It is permanently covered by ice because of the ALBEDO: snow and ice reflect most of the incoming solar radiation, keeping Greenland in its own deep freeze.

Glacial( Polar) Climates Glacial environments contain snow and ice all year round. Antarctic temperatures are low all year round, varying from -60 degrees on the ice sheet to -10 degrees on the coast. There is considerable variation in amount of precipitation that’s falls in Antarctica. Cold mountain winds blow out from the centre of Antarctica towards the edge of the continent – called KATABATIC WINDS. These winds form as dense cold air over the central plateau drains into depressions and valleys. Examples of Glacial climate – Greenland, Antarctica.

Periglacial Climates Periglacial zones have a significant cover of snow and ice but not all year round. Found in areas of high altitude or high latitude. Periglacial areas are characterised by large seasonal temperature ranges. Temperatures in calm clear winter are -50 degrees although spring temperatures rise above freezing and in summer temperatures may rise to over 20 degrees because: –High latitude – receive small amount of insolation due to the low angle of the overhead sun. –High altitude – Temperatures decline on average 1 degree for every 100m climbed. –Albedo – they reflect solar radiation – average absorption is 40%, on dark soils is 90% and on snow 10-20%.

Periglacial Climates Precipitation levels in periglacial environments are generally low – due to low air temperatures, since cold air is only able to hold small amounts of moisture. Many periglacial areas are affected by high pressure conditions that also reduce the amount of rainfall. In the Arctic, rainfall declines away from oceans, as the westerly depressions progressively lose moisture as they travel.

Mountain (upland) Climates Areas which were once covered in ice but are now free from snow and ice. The landforms formed during cold periods continue to exert influence over the area – many are periglacial but this is not always the case. Some mountainous areas are so high (Alps, Himalayas) they contain glaciers and ice caps. All mountain climates are: –Cool – loose 1 degree for every 100m or 10 degrees per km. –Wet – cause relief or Orographic rainfall.

Where are cold environments? Using a key, mark on and label the world outline map areas of glacial, periglacial and mountain climates.

Climate graph analysis Compare and contrast the climate graphs for Ambleside, Norway and Siberia. Include the following: Figures – temperature and rainfall. Range of Temperature. Seasonality. You can look on P91 of text book for the minimum and maximum temperatures.

Who am I? I am very cold in winter but can be above freezing in summer. I don’t get much precipitation but I am covered in snow and ice for some of the year. I am a Periglacial Environment I am cold mountain winds that cause temperature to always be below freezing. I am Katabatic Winds I am cool and wet. In the winter it can be freezing but in the summer it can reach 20 degrees. I am a mountainous area.