Living with the physical environmentSection B: Living World

Desertification

What is desertification?

http://www.bbc.co.uk/bitesize/ks3/geography/places/extreme_environments/revision/10/

Use the map below to describe the location of regions at risk of desertification. Give two descriptions: (remember to use latitude lines, continents, compass directions)1 _________________________________________________________________________2 _________________________________________________________________________

Cause of desertification 1: climate change

Using the graph below, describe how annual rainfall has changed in the Sahel region (just below the Sahara Desert) since 1900.

1 __________________________________________________________________________2 __________________________________________________________________________

Read the information below and answer these questions:a) What are scientists struggling to predict changes in? _________________________b) Why do they think global warming might bring an increase in rainfall to the Sahel?

______________________________________________________________________c) What would happen to the Sahel if there was more rain? ___________________________d) What would happen to the Sahel if the climate becomes drier?

______________________________________________________________________

Natural climate change has occurred in the past so changes to the rainfall in the Sahel may have happened anyway, even without human-induced global warming. We do not know whether global warming will create even greater rainfall shortages in the Sahel and other desert fringes. While many scientists are certain that global temperatures will rise this century, they are less confident when it comes to predicting how rainfall patterns will change. Some think there is a possibility of rain retuning to the Sahel as a result of global warming, as the heating of oceans adds more water vapour to the atmosphere. This could, in turn, bring more rainfall that leads to the ‘greening’ of the Sahel. However, it may be that the climate becomes even drier, leading to the spread of sand dune systems across valuable crop land.

Cause of desertification 2 & 3: population growth and removal of fuel wood

Population growth remains high in the poorest parts of the Sahel. In 1950, there were just 30 million people living in the Sahel. Now, there it is closer to half a billion (1 thousand million). By 2050 it is expected to ready one billion. The population has grown quickly due to a high number of babies being born, large numbers of refugees coming from war zones across Africa, and from areas that have already suffered desertification, and people living longer than they used to.Refugee camps create new environmental stresses wherever they are located and cause desertification to spread as people use the trees for firewood. When people return home, further desertification is expected. One charity estimates that each returning family will need 30-40 trees to rebuild their houses and fences. The desert fringes of the Sahel do not have enough trees to support this.

Using the information above:a) How many more people are there now in the Sahel? b) Other than babies being born, give one more reason why the Sahel’s population is

growing. ______________________________________________________________________c) Give two ways refugees contribute to desertification.

____________________________________________________________________________________________________________________________________________

Watch the clip in this link which discusses the main ideas above and answer the questions below:http://www.bbc.co.uk/bitesize/ks3/geography/places/extreme_environments/revision/10/

Going back 50 years, how many kilometres further north was the Sahara desert? _________

What did newcomers to the Sahel in the 1950s do to the land that led eventually to its desertification?

They followed modern European farming methods – they introduced herds of ___________dependent cattle.They cleared large areas of natural vegetation for ____________ and _______________Trees were cut down for _________________ materials and ________________More people meant more ________________was needed so more ______________were introduced and more _______________ established. The natural vegetation became overgrazed. Climate changed. In ____________ it stopped raining and the cattle died and crops withered. ________________ people died____ countries are affected.The next 30 years brought prolonged drought. Green land transformed into a ______________. Without vegetation and moisture, the soil degraded into ________________ and turned into desert.

Cause of desertification 4 - 6: overgrazing, over-cultivation, soil erosion

Look at the photos and read the information in the table to answer these questions:

Overcultivation (overcropping)Why are people planting more crops?

Cash crops are grown to be sold rather than eaten by the farmers. Why are cash crops going to lead to desertification in Ghana?OvergrazingWhat is overgrazing?

How were nomadic herders using the land in a sustainable way? What did nomadic herders used to do?Give one reason why nomadic herders are now overgrazing the land/staying too long in places.

Soil erosionComplete this diagram using the following labels:

wind soil rootsintercept cracks exposed

Strategies used to reduce the risk of desertification 1 – water and soil management

Terraces are cut into steep hillsides to stop what? Look at the picture and its description.___________________________________________________________________________

Using both the picture and the diagram, answer the questions below:

What are bunds?

How far apart are they spaced?

Bunds slow surface run-off which means there is more time for what?

Other than water, what else is trapped by the bund?

Watch this clip and answer the questions:https://www.youtube.com/watch?v=dO16g4LgBjI

What can they use if they don’t have enough stones for the bunds (walls)?

How well have these stone lines worked?

How have these stones walls helped farmers?

Strategies used to reduce the risk of desertification 2: tree planting

Watch these clips and answer the questions:

https://www.youtube.com/watch?v=X9Kyh8Nv01A

What is the Great Green Wall a wall of?

How long is the Great Green Wall?

What is it trying to stop?

How many countries are involved?

When did it start?

Is it working?

https://www.youtube.com/watch?v=bdRDfXFjgZg

How percentage of the African continent does the Sahara desert cover?

How wide is the Great Green Wall?

Which was the first country to start planting?

If you are a Target Grade 7 or above, answer these questions:How does this stop desertification?

Not solely about stopping desertification. What are they now planting?

How has it affected the people and the economy?

All pupils:Find a map of the Great Green Wall of Africa that shows the countries the wall goes through.

Strategies used to reduce the risk of desertification 3: use of appropriate technology

Appropriate technology is technology suited to the needs, skills, knowledge and wealth of the local people and their environment.

Removing trees for firewood is one of the most damaging human activities in desert fringe areas like the Sahel. For millions of years, people have been using wood as a cooking fuel. They often turn the wood into charcoal.

Use the information above to answer these two questions:

Do you think appropriate technology in the African Sahel will involve small or large amounts of money?

What do they turn the wood into?

Watch the clip about Toyola stoves in Ghana then answer these questions (you may need to watch the first minute or so first before answering the questions):

https://www.youtube.com/watch?v=2gQmOl2e-vQ

What are the stoves made out of?

Give two things that are reduced because of these stoves.

These stoves are energy efficient. How much less charcoal do they use?

Workers get trained for free. What do they have to do in return?

Give two positives of the stoves:

How do Toyola stove cut greenhouse gas emissions?

How much are the stoves?

How do people pay for them?

Find a picture of a Toyola stove:

Solar powered cooking

Watch the clip below and answer the questions:https://www.youtube.com/watch?v=uY95ESUYK7Y

Why do they have to use solar power?

Why do the women like the solar power cooking?

Give one drawback of using solar power to cook.

How are they made?

Find a picture of a solar stove: