What caused the Sahel to expand in recent years?
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| Question | Answer |
|---|---|
| What is causing the Sahel to expand in recent years? | Over-grazing and cutting down trees for fuel |
Why the Sahara Desert is expanding?
First of all, the Sahara is not expanding into the rest of Africa. Drought in the Sahel in the 1970s and 1980s made it look like the desert was expanding, because the reduction of rainfall at the desert margin (the Sahel) caused a reduction in vegetation. The Sahara is a desert because it receives negligible rainfall.
How have deserts changed in recent years?
Global warming is increasing the incidence of drought, which dries up water holes. Higher temperatures may produce an increasing number of wildfires that alter desert landscapes by eliminating slow-growing trees and shrubs and replacing them with fast-growing grasses.
What caused the desertification in Sahel?
The Sahel is a narrow belt of land which lies immediately to the south of the Sahara Desert and which extends across most of Africa. The main causes of desertification include: Overgrazing – an increasing population results in larger desert areas being farmed. Sheep, cattle and goats are overgrazing the vegetation.
How does the drought affect the economy?
Examples of economic impacts include farmers who lose money because drought destroyed their crops or ranchers who may have to spend more money to feed and water their animals. Plants and animals depend on water, just as people do. Drought can shrink their food supplies and damage their habitats.
How can we prevent flooding?
Natural flood management Measures might include using small barriers in ditches and fields, or notches cut into embankments, to divert the water into open land. Letting pools form outside the main channel of a river means the water is temporarily removed from the main flow – reducing the power of the floodwaters.
How can flood be controlled?
Floods can be controlled by redirecting excess water to purpose-built canals or floodways, which in turn divert the water to temporary holding ponds or other bodies of water where there is a lower risk or impact to flooding. Channelisation is a deliberate attempt to alter the natural geometry of the river.
What are some flood Defences?
More modern flood defences can include:
- Dams.
- Diversion canals.
- Floodplains and groundwater replenishment.
- River defences, e.g. levees, bunds, reservoirs, weirs, and so on.
- Coastal defences, e.g. groynes, sea walls, revetments, gabions, and so on.
- Retention ponds.
- Moveable gates and barriers.