The cumulative cause of desertification is outlined. The cycle begins when vegetation is removed. This vegetation would normally hold moisture, which evaporates into the atmosphere due to the warm climate. The evaporated moisture condenses to form clouds and rainfall normally occurs in the afternoons. If the vegetation is removed, the soil becomes drier and there is less moisture available for evaporation. Rainfall decreases and dry soil can easily be blown away.
- This clip is from:
- First broadcast:
- 18 October 2007
If you have already covered convectional rainfall, ask pupils to remind you what it is. Ask them to imagine covectional rainfall without water existing on the surface and in plants to begin with - i.e. to predict what would happen. Play the whole clip through, asking students to sketch cartoons of the water cycle before desertification on one side of a mini whiteboard, and the water cycle during desertification on the other. Pick the clearest sketches and then you, or the student, could sketch them on the board, complete with annotations, for the class to copy in neat. Or provide the sketch, and pupils annotate it. Alternatively, provide the annotations on a worksheet and pupils would provide the sketch.