global distribution OF EXTREME ENVIRONMENTS

DESCRIBING DISTRIBUTION

Distribution refers to the way something is spread out or arranged over a geographic area. Describing distribution is an important skill for IB Geography. Referring to global subregions in your answer is a useful way to gain extra marks.

TASK 1: Study the maps below and write a description of the distribution using the key words below to help.

north/south/east/west                          named continents/regions                         coastal/inland                     highest/lowest                                         hemisphere                            tropics/mid latitude/polar    

GLOBAL DISTRIBUTION OF COLD & HIGH ALTITUDE ENVIRONMENTS

In the Köppen climate system, polar climates are defined as the warmest temperature of any month being below 10 °C (50 °F). Polar climates are further divided into two types, tundra climates and icecap climates (Source).

GLOBAL DISTRIBUTION OF HOT, ARID ENVIRONMENTS

Hot, arid climates are characterised by the amount of annual precipitation less than a threshold value that approximates the potential loss of moisture by evapotranspiration. (Source)

TASK 2: DISTRIBUTION AND CHARACTERISTICS OF EXTREME ENVIRONMENTS

1. Research and present an overview of the distribution and characteristics of each of the following climate zones:

   • Polar climate

   • Tundra climate

   • Hot desert climate

   • Hot semi-arid climate

REASONS FOR COLD TEMPERATURES

REASONS FOR ARIDITY

REVIEW

Form pairs with person A unable to see the diagrams. Person B describes the picture for A to draw.

TASK 1: Compare and contrast the climate of the two places below. Include data in your answer.

CLIMATE AND RELIEF OF EXTREME ENVIRONMENTS

MYSTERY IMAGE

TASK 3: What has happened to the vehicle in the photo below?

FLASH FLOODS

An arid area receives less than 250 mm of rain per year.

Most deserts get what little precipitation they do receive in a few, heavy rainfalls, rather than many light rains spread out over the course of the year. This leads to seasonal lakes and rivers which may last a few months, or even only a few days. Dry river beds are a common sight in many deserts, and are called wadis in some African and Middle Eastern deserts.

In order to understand how a flash flood like the one above can happen in hot, arid areas, we must first understand how drainage basins work.

TASK 3: Study the diagram. Identify the processes which would be affected by:

• extreme high temperatures

• lack of vegetation cover

CAUSES OF FLASH FLOODS IN ARID AREAS

TASK 4: Draw a labelled diagram including all of the information below

Flooding occurs when rainfall intensity exceeds infiltration capacity generating surface runoff/overland flow leading to flooding.

Causes of flooding in deserts:

1. summer convection rainfall bringing high amounts of precipitation

2. unvegetated desert surfaces reduce interception and infiltration, increasing overland flow

3. high concentrations of water in wadis, gullies or channels

4. presence of desert crusts (duricrusts) and other barriers to infiltration (rocks in desert pavement etc).

practice exam question

Describe the climatic characteristics of either periglacial or glacial environments. [4 marks]

Mark Scheme

Key aspects will be temperature, temperature range, seasonality, precipitation.

Award 1 mark for each valid statement, supported by some quantification or development.

Study the image of a high-mountain area below. State the characteristics which present challenges for human habitation (housing, road and communication infrastructure) and resource development (agriculture, mineral extraction).

PERIGLACIAL ENVIRONMENTS

TASK 1: Watch the videos and note how challenges (relief, climate, human discomfort, inaccessibility, and remoteness) present challenges for human habitation and resource development

CHALLENGES OF PERIGLACIAL ENVIRONMENTS

Periglacial environments have a cold climate and are frequently marginal (next to) to glacial environments. These areas are subject to intense cycles of freezing and thawing of surface sediments. 

Permafrost is soil, rock or sediment that is frozen for more than two consecutive years. Permafrost is closely associated with periglacial environments and permafrost processes take place within a periglacial environment

CHALLENGES OF PERMAFROST

TASK 2: Access the resources and make notes on how periglacial environments create challenges for human habitation and resource development, as well as the measures used to overcome them.

HUMAN HABITATION AND RESOURCE DEVELOPMENT

Illustrate the challenges and explain how they affect human habitation and resource development.

RESOURCE DEVELOPMENT IN PERIGLACIAL AREAS

CASE STUDY: TRANS-ALASKA PIPELINE

1. Research the trans-Alaska pipeline and note some key facts

2. Watch the video documentary and complete the A3 writing frame

List as many causes of climate change as you can. Prepare to share these with the class.

NATURAL CLIMATE CYCLES

TASK 1: Read the text and watch the video. Explain the natural (non-human) causes of climate change.

Human activity is undeniably linked to an increase in CO2 in the atmosphere, which is changing the Earth’s climate. However, climate has been constantly changing throughout history.

If the distribution of extreme environments is dictated by the type of climate, changes to climate therefore influence the distribution of extreme environments. In order to understand historic changes to the distribution of extreme environments, we must therefore first understand that natural changes to climate have influenced the distribution of extreme environments over time.

Watch the video above and make notes on the natural causes of climate change.

COLD & HIGH ALTITUDE ENVIRONMENTS

TASK 2: Watch the video and answer the questions below:

Questions:

1. Name the different types of glacier.

2. Explain how glaciers form.

3. Outline why glaciers an important resource for humans.

4. Describe how are glaciers changing and what the causes for this are.

THE GLACIAL SYSTEM

Glaciers are the products of a system which includes inputs, storage and outputs. The balance between these is called the glacial budget or glacial regime.

GLACIAL BUDGET

accumulation > ablation, glacier advances

accumulation < ablation, glacier recedes

accumulation = ablation, glacier maintains same size

CLIMATE CHANGE AND HOT, ARID ENVIRONMENTS

Desertification is a type of land degradation in which a relatively dry area of land becomes a desert, typically losing its bodies of water as well as vegetation and wildlife. It is caused by a variety of factors, such as through natural and anthropogenic (human caused) climate change (particularly the current global warming) and through the overexploitation of soil through human activity.

When deserts appear automatically over the natural course of a planet's life cycle, then it can be called a natural phenomenon; however, when deserts emerge due to the rampant and unchecked depletion of nutrients in soil that are essential for it to remain arable, then a virtual "soil death" can be spoken of, which traces its cause back to human overexploitation.

Desertification is a significant global ecological and environmental problem with far reaching consequences on socio-economic and political conditions. (Source)

HUMAN-INDUCED DESERTIFICATION

NATURAL DESERTIFICATION

EXTRA RESOURCES