JSS3 First Term Basic Science Lesson Note – Desertification and Depletion of the Ozone Layer

The content is just an excerpt from the complete note for JSS3 First Term Basic Science Lesson Note – Desertification and Depletion of the Ozone Layer. Check below to download the complete PDF

WEEK FIVE

TOPIC: ENVIRONMENTAL HAZARDS (3)

SUB-TOPIC: DESERTIFICATION AND DEPLETION OF THE OZONE LAYER

 DESERTIFICATION

Definition of Desertification or Desert Encroachment

Desertification is the degradation of land in any dry land.It is caused by a variety of factors, such as climate change and human activities. Desertification is a significant global ecological and environmental problem.

It can also be defined as a process of land degradation which occur mainly in arid regions or semi-arid regions where rainfall is unreliable which can be compounded by different human activities that lead to mismanagement of the environment

GEOGRAPHICAL AREAS

Dry lands occupy approximately 40–41% of earth’s land area and are home to more than 2 billion people. It has been estimated that some 10–20% of dry lands are already degraded, the total area affected by desertification being between 6 and 12 million square kilometres, about 1–6% of the inhabitants of dry lands live in desertified areas, and that a billion people are under threat from further desertification.

The Sahara is currently expanding at a rate of 48 kilometers per year.

Some geographical areas are more prone to becoming deserts than others. Geographical areas where rainfall is not heavy and regular are prone to desertification. Northern states of Nigeria such as Sokoto, Kano, Katsina, Jigawa and Borno have low and irregular rainfall. These states are threatened by desertification.

CAUSES OF DESERTIFICATION

1. Over cultivation of desert land: The most common cause of desertification is the over cultivation of desert lands. Over cultivation causes the nutrients in the soil to be depleted faster than they are restored
2. Overgrazing of dry lands is one of the primary causes of desertification. Overgrazing removes vegetation causing erosion and loss of topsoil.
3. Poverty;

To gain full access to the note: DOWNLOAD FILE