This is a continuation of what you learned about environmental hazards in Weeks 3-6. You learned about soil erosion and flooding in weeks 3 and 4, then bush burning and deforestation in weeks 5 and 6. You will learn about deserts and ozone layer depletion in weeks 7 and 8.


A desert is a large region of land with little or no rain and few plants. Desertification is the process by which a non-desert area becomes a desert. Desertification occurs when a land that was formerly covered by vegetation changes owing to some event, such as drought, to one that is no longer covered by vegetation. Some locations are more vulnerable to desertification than others. Those with regular rainfall, such as the southern parts of Nigeria, are not prone to desertification, whereas areas with little and irregular rainfall, such as the northern part of Nigeria, are.

Deserts cover around 50% to 75% of Nigeria’s northeast and northwest states. Deserts may be found in Bauchi, Bornu, Gombe, Taraba, Jigawa, Kano, Katsina, Kebbi, Sokoto, Yobe, and Zamfara states. Desertification, like other environmental hazards, is heavily impacted by climate change and human activity.

List Of Some Deserts In Africa

  1. The Sahara desert is the largest hot desert found in North Africa.
  2. Namid desert found in Southern Africa.
  3. Kalahari desert is also found in Southern Africa.

Causes of desertification

The following are the causes of desertification:

  • Deforestation 
  • Bush burning, 
  • Overgrazing
  • Drought
  • Soil erosion
  • Climate change 
  • Increasing salinity

How To Control Desertification

  1. The government should educate the public about the negative impacts of desertification.
  2. The government should make desertification a crime punishable by law.
  3. Restoration of soil fertility by the planting of leguminous crops.
  4. Creation of artificial channels to hold rainwater and capture windblown seed.
  5. The planting of trees and cover crops.

Depletion Of The Ozone Layer

Ozone has the chemical formula O3 and comprises three oxygen atoms. The exosphere, thermosphere, mesosphere, stratosphere, and troposphere are the five layers of the atmosphere. The lower stratosphere contains the ozone layer. The sun not only provides heat and light, but it also emits ultraviolet radiation. Ultraviolet rays are extremely dangerous to our health. They cause plant damage and skin cancer in humans. The ozone layer’s job is to absorb the sun’s ultraviolet radiation, protecting people and other species from its effects.

Despite the ozone layer’s function, it is being depleted by the accumulation of a chemical used in refrigerators called chlorofluorocarbon (CFC) in the atmosphere.

The ozone layer is depleted when chlorine from CFCs combines with ozone to create chlorine monoxide (CIO) and oxygen gas. The reaction of two CIO molecules results in the formation of chlorine peroxide (CI?O?). In the presence of sunshine, the CI?O? is then broken down into oxygen (O2) and free chlorine atoms (2CI)

Importance Of Ozone Layer

  1. Ozone is essential in the manufacture of medications and synthetic lubricants.
  2. Ozone is utilised in the bleaching process.
  3. Ozone is utilised in water systems to destroy bacteria.
  4. The ozone layer shields the planet from the sun’s radiation.
  5. The ozone layer protects humans, animals, and plants from the sun’s damaging UV radiation.

Industrial Uses Of Ozone

Industrially ozone is used to:

  1. use for Cleaning the laundry in hospitals and food factories.
  2. Remove smells from the air, especially after a fire.
  3. help with processing plastics so that inks can stick to them.
  4. used in Washing fresh fruits and vegetables to kill yeast, mould, and germs.

The Harmful Effects Of The Depletion Of The Ozone Layer

  1. The buildup of carbon (IV) oxide (CO?) in the atmosphere is what causes global warming. The greenhouse effect is caused by more CO2 in the air (a phenomenon in which the heat of the sun can come to the earth but cannot be radiated back to the atmosphere).
  2. The effect of greenhouse gases on the temperature of the earth is called “global warming.”
  3. When the earth’s temperature goes up, more ice melts, which causes water bodies to overflow and cause flooding.
  4. Exposure of human and animal skin to the sun’s harmful ultraviolet rays, can cause skin cancer.
  5. When the ozone layer is depleted, more ultraviolet rays can reach us. These rays could hurt aquatic plants and animals, which would upset the ecosystem.
  6. When the ozone layer is depleted, the amount of greenhouse gases goes up, which warms the earth too much and changes the seasons. When the ozone layer is depleted in the lower atmosphere, the number of toxic gases may go up. 
  7. Scientists also think that there are a lot of bad effects that haven’t been found yet.

Control Measures Against Depletion Of Ozone

There are control measures that can be taken to limit the depletion of the ozone layer. Some of these measures are:

1. Putting rules on how chlorofluorocarbons can be used (CFC).

2. Putting rules on burning trees and other things that put CO2 into the air.

3. Planting trees to lower the amount of carbon dioxide in the air (plants use CO2 for photosynthesis).

4. Burning must be kept under control when doing things around the house.

5. Getting rid of the chemicals that are causing the depletion ozone layer

6. Reducing the number of toxic gases that can harm the ozone layer.

7. The creation of technology that will keep dangerous gases from coming out of equipment like refrigerators, air conditioners, and other home appliances.

Global Warming

Global warming is the increase in the average temperature of the earth over a prolonged period of time.

 Major Causes Of Global Warming

  1. depletion of the ozone layer
  2. greenhouse effect (increase in greenhouse gases).

The greenhouse effect is caused by the accumulation of greenhouse gases in the lower atmosphere (CO2, H2O, and CH4), which cause heat to be reflected back to the earth. CO2 is the most important greenhouse gas. The greenhouse effect and global warming are both caused in large part by the increase in carbon dioxide in the atmosphere.

Consequences Of Global Warming

  1. Seasonal/climate change.
  2. Rising oceans.
  3. Increase in flooding occurrences.
  4. Melting ice caps or polar ice.
  5. Increase in the average temperature of the world.

Control Of Global Warming

Global warming can be controlled through the following activities.

  1. Planting trees will clean the air because they will take in carbon dioxide for photosynthesis and give off oxygen, which helps make the ozone layer.
  2. Less burning of bush and waste.
  3. Reusing and recycling old materials.
  4. Use sources of energy besides fossil fuels, such as solar power, wind turbines, and water turbines.
  5. To cut down on carbon dioxide emissions, people should drive electric cars.

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