Desertification - Paper 1

Question 1

Define desertification:

Answer 1

Desertification is the process of land becoming a desert as the quality of soil degrades/ declines overtime.

Question 2

How many people live in areas at risk of deforestation?

Answer 2

An estimated 1 billion.

Question 3

Give 5 reasons why vegetation is so vital to the protection of soil in dry areas?

Answer 3

-Roots bind soil together
-Vegetation provides shade to maintain moisture and prevent drying out
-Can reduce air temperature by up to 20°C
-Leaves intercept rain and stop soil erosion with initial force, water can drip gently down instead
-Plants prevent surface of soil being baked in the heat and prevents water being drawn up by evaporation

Question 4

What are the 6 causes of desertification?

Answer 4

-Climate change
-Population growth
-Removal of fuelwood
-Over-grazing
-Over-cultivation
-Soil erosion

Question 5

What is an example of climate change causing desertification?

Answer 5

Since the 1970s, the Sahel Region of West Africa has experienced significant reductions in annual rainfall, with just the occasional year receiving higher than average rainfall.

Question 6

What is an example of population growth causing desertification?

Answer 6

In the Sahel region, the population has increased from 30 million people in 1950 to almost 500 million today. This is expected to double by 2050. In increase in demand for food has put the land under enormous pressure, leading to vegetation destruction, soil erosion and ultimately desertification.

Question 7

How many people living in semi-arid conditions depend upon wood as their primary source of fuel?

Answer 7

Millions.

Question 8

What happens to land as it is stripped of its trees? (removal of fuelwood)

Answer 8

It becomes vulnerable to erosion by wind and rain and it can quickly become degraded and turn to desert.

Question 9

Why does overgrazing often happen?

Answer 9

Because the available pasture land is reduced by natural causes (eg drought) or human factors (eg political conflicts). Population pressure can also lead to overgrazing.

Question 10

How is over-cultivation different to over-grazing?

Answer 10

Over-cultivation exhausts the soil of its nutrients and it can quickly become infertile.

Question 11

How does soil erosion lead to desertification?

Answer 11

When vegetation is stripped or killed, soil is left bare and baked by the sun. When it rains, it washes over the hard surface, removing rills and gullies and washing away topsoil. This leaves behind very infertile sub-soil that cannot be used for anything.

Question 12

What 3 factors of desertification come from population growth?

Answer 12

-Removal of fuelwood
-Over-cultivation
-Over-grazing

Question 13

What 3 strategies can be used to reduce the risk of desertification?

Answer 13

-Water and soil management
-Tree planting
-Use of appropriate technology/intermediate technology

Question 14

Describe an example of water and soil management to reduce the risk of desertification:

Answer 14

Bunds - A series of low rock walls which are deliberately constructed to follow the contours of the land, interrupting the downslope flow of surface water. Any soil carried by the water is deposited on the upslope side of the walls, creating a reasonable thickness of soil that can then be cultivated.

Question 15

Describe an example of tree planting to reduce the risk of desertification in India:

Answer 15

In the Thar desert, India, the Prosopis cineraria tree has been planted to address the problem of desertification. It is well adapted to desert conditions and, if managed correctly, will provide foliage and seed pods for animals to eat and wood for fire wood and building.

Question 16

Describe an example of tree planting to reduce the risk of desertification in Africa:

Answer 16

In 2007, the African Union launched a project called the ‘Great Green Wall’ to plant trees across the Southern edge of the Sahara Desert to reduce desertification and address issues such as water management and food security.

Question 17

How many African countries are involved in the ‘Green Green Wall’ project?

Answer 17

21 African countries.

Question 18

How much land, in what country, has already been restored thanks to the ‘Great Green Wall’ project?

Answer 18

15 million hectares of land have been restored in Ethiopia alone.

Question 19

Name 2 appropriate technologies that can be used in a variety of ways to address desertification:

Answer 19

-Bunds
-Alternative cooking devices that use efficient stoves

Question 20

How can stoves be made efficient to reduce desertification?

Answer 20

They can burn only small amounts of wood or charcoal, reducing the quantity if fuelwood required.

Question 21

Who often supplies alternative cooking devcies?

Answer 21

Charities such as Practical Action.

Question 22

What do we mean by appropriate technology?

Answer 22

Any technology designed for the community it’s intended for.

Question 23

Name 2 defects of the Great Green Wall:

Answer 23

-Very expensive
-Will take a long time to build

Question 24

What tree species can be planted to reduce desertification?

Answer 24

Acacia trees.

Question 25

What are planting pits?

Answer 25

It involves digging a hollow in the soil and planting crops in them. They collect rainfall and runoff which means there is a regular supply of water to the plants.