2 DesertDesert is a dry region. It receives less than 250mm of rain a year.Climatic characteristicsRainfall:Less than 250mm rainfall a year.Rainfall is irregular.There may be no rain for several years. When the rain comes, it occurs in the form of short and heavy thunderstorms.Temperature:Very hot during the day. Very cold at night. Large diurnal range of temperature.
3 Areas in danger of desertification Major deserts in the world
4 What is desertification? Five years laterDesertification is the process by which the desert spreads intothe surrounding areas.
5 Areas in danger of desertification Major deserts in the world
7 Rainfall and natural vegetation in the Sahel DesertGrassland and woodlandRainforestAnnualrainfallLessthan250mm,000mmMore than2,000 mm
8 Where is the Sahel? The Sahel is a narrow belt of land in Africa. It is located between the dry desert land to the north and the forest areas to the south.Temperatures are always high and there is a long dry season.Most rain comes during the summer. There is more rain in the south and rainfall decreases towards the desert in the north.The natural vegetation is mainly grassland.
9 Causes of desertification in the Sahel Long period of droughtSoil becomes loose and dry.Land become bare.
10 Causes of desertification in the Sahel Long period of droughtAs a result . . .WindWaterSoil erosion occurs.Land becomes desert like-land.
11 Drought Rainfall is highly unreliable. In this long period of drought, vegetation has died. The land has become bare.The soil becomes dry and loose.The loose soil is easily removed by wind and water.Soil erosion takes place.Areas without vegetation cover will turn into desert-like land.
12 Causes of desertification in the Sahel Population growth and human activities
13 Causes of desertification in the Sahel Population growth and human activitiesdemand for food increasesExpansion of farmlandovercultivation overgrazing
14 Causes of desertification in the Sahel Population growth and human activitiesOvercutting of fuelwoodTrees cannot grow fast enough to recover themselves.Soil erosion occurs.
15 Causes of desertification in the Sahel Population growth and human activitiesPoor irrigationThe soil becomes verysalty and crops die.Irrigation water bring mineral salts to the surface.Salty soil is not suitable for crop growth.
16 A summary of the causes of desertification DroughtPopulation growthLand becomes bareOvergrazingExpansion of farmlandSoil erosionOvercultivationOvercutting of fuelwoodPoor irrigationDesertification
17 What are the results of desertification? Loss of soil fertility andvegetation becomes damagedLess food productionwidespread malnutritionand starvation
18 Ways to stop desertification in the Sahel 3. Birth control to reduce birth rates4. Large-scale dams to store water for irrigation and HEP6. Planting fast-growing trees for fuelwood1. Rearing good quality cattle7. Hand dug irrigation canals2. Planting fast-growing grass5. Growing high-yielding crops
19 Problems with the measures to stop desertification Most Sahelian countries are politically unstable.Civil wars are frequent.It is difficult to carry out development plans.Birth control has failed. Population pressure remains very high.The countries in the Sahel are very poor and heavily in debt. Most of the money borrowed has been spent on developing industries and infrastructure.The government lacks the experts to carry out the development plans. People do not know how to use the new technology.
20 How can we help? Desertification is a global problem Rich countries offer financial and technicalhelp to poor countriessuch as World Vision and Oxfam provide food and medicine to the local peopleVoluntary relief organisationsdonate money and join operations organised by the relief organisationsIndividuals