Opportunities and Constraints for human activities in the CTWM and Monsoon climates

1
6th May 2005
CW

• 2 part lesson-
• Desertification
• Acid Rain

• Lesson Aims
• To identify what desertification is and what
  causes it
• To understand the effect Acid rain is having on
  the environment

2
Drought

• Drought is a hazard in many parts of the world
• It is an abnormal condition and should not be
  confused with an annual dry season

3
Drought in Africa- The Sahel

• The Sahel region has become synonymous with
  drought

• DROUGHTS HAVE PLAGUED THE LAND HERE IN THE SAHEL
  STRETCHING FROM WEST AFRICA EASTWARDS FOR FIVE
  YEARS BUT IS DROUGHT HERE REALLY THE PROBLEM?
• LAND USE PRACTICES HAVE CAUSED THE DEATHS OF
  MORE THAN 100,000 PEOPLE
• OVER 12 MILLION CATTLE HAVE DIED
• SOCIAL ORGANISATIONS HAVE BEEN DISRUPTED ON A
  NATIONAL SCALE

4
What causes the drought in the Sahel?

• There are both natural and human causes of the
  drought in the Sahel
• The droughts can lead to
• Desertification

5
Human causes of the drought in the Sahel

• The Sahel regions are areas which experience
  desertification

6
DESERTIFICATION

• What is desertification?

Desertification is when a desert gradually
spreads to the surrounding areas of semi-desert
7

• Why does the Sahel suffer from desertification?

DESERTIFICATION
Increase in cattle
Increase in population
Deforestation for fire wood
Grassland grazed more intensively
Roots no longer hold soil together
Roots may be eaten as well as grass
Less vegetation means less protection from weather
Leaves no longer protect soil from weather
Loose top soil blown away by wind (Soil
Erosion)
Loose top soil blown away by wind (Soil
Erosion)
DESERTIFICATION
8
This man is a farmer. Why is he looking up to the
sky?
9
Task

• Key Geography Pages 126-127
• Read through
• Answer Question 1 2

10
Acid rain

• It is a type of air pollution
• Caused mainly by power stations and industries
  burning fossil fuels which give off sulphur
  dioxide and nitrogen oxide
• Nitrous oxide from car exhausts add to the
  problem
• The chemicals in acid rain are carried up into
  the atmosphere, and spread over a wide area by
  the prevailing wind
• It can be very damaging to the environment

11
Major Problem-

• The countries that are producing the majority of
  the Pollution that causes acid rain (Britain,
  Germany, USA) arent that badly affected by acid
  rain
• Instead, the wind direction means the acid rain
  falls elsewhere (in Europe this affect
  Scandinavia USA affects Canada)

12
Tasks

• Read Key Geography pages 116-117
• Answer Activities 1-5

13
Homework

• This is the end of the Climate, the Environments
  People unit
• All I want you to do for your homework is to read
  the case study sheet on Desertification in the
  Sahel (case study 13)