SSA - Physical Geography Lesson

Physical Geography

Physical Geography of Sub-Saharan Africa

Sub-Saharan Africa, as the name suggests, includes the African countries that contain lands or regions south of the Sahara Desert. The African Transition Zone cuts across the southern edge of the Sahara Desert at the widest portion of the continent. To further aid the study of the continent, the continent can be further broken down into regional components: Central Africa, East Africa, West Africa, and Southern Africa. The term Southern Africa is used because South Africa is a country in Africa. The southern tip of the continent—off South Africa—is often referred to as the Cape of Good Hope, where the Atlantic Ocean meets the Indian Ocean.

The African Transition Zone divides North Africa from the rest of Africa because of climatic and cultural dynamics. Cultural conflicts and desertification are common in the zone. Dry, arid type B climates, common in the Sahara Desert, are dominant north of the zone. The shifting sands of the Sahara are slowly moving southward toward the tropics. Desertification in the zone continues as natural conditions and human activity place pressure on the region through overgrazing and the lack of precipitation. 

Lake Chad in the north is a large, shallow body of water that lies on the border of Chad, Niger, Nigeria, and Cameroon. Climatic conditions and human activities have caused the water to recede tremendously. If these conditions continue, the lake might disappear causing disastrous effects on both the human population and the biodiversity which includes waterfowl, crocodiles, fish, and a host of other creatures.

Climates 

With such a large land mass, the continent of Africa spans across many latitudes. Students should recall from the earlier lessons that latitude is one of several factors which influence an area's climate. The climates of Africa include:

• Savannah - Type A (Am, Aw) climates that are a bit drier are found to the north and south of the rain forest areas. They have distinct wet and dry seasons.
• Tropical rainforest - Type A (Af) climates that are found in the center of the continent and along the eastern coast of Madagascar.
• Steppe - Type B (BSh, BSk) climates appear as one travels away from the Equator, either north or south, the savannah grades into drier steppe.
• Desert - Type B (BWh) climates have little rainfall and wide differences between day and night temperatures. The Sahara in the north is the world's largest desert. The Kalahari in southern Africa covers an area larger than France.
• Humid sub-tropical - Type C (Cfa) climates are found in the southwest.
• Marine - Type C (Cfb) climates are largely in the southeast.
• Mediterranean - Type C (Csa) climates are mostly on the northwest (Mediterranean) coast and in the southeast.
• Highland - Type H climates are largely found in the east, below the Horn of Africa in areas with high elevations. These are not shown on the images.

The equator runs through the middle of Central Africa. Type A climates are dominant in the region, complete with tropical rain forests and jungle environments. The savannah regions of the east and south, with their drier Type A climates, have seasonal rains (wet/dry seasons) that affect the growing season. Soils in savannah areas are not capable of producing large food crops and cannot be depended on to fulfill the agricultural needs of a growing population. For this reason, savannahs are usually grasslands or scrub forests used for grazing cattle and livestock.

Southern Africa includes both type B and type C climates. The Tropic of Capricorn runs straight through the middle of the region, placing the most southern portion of the continent outside the tropics. This subtropical region lies in the area known as the Horse Latitudes. The high pressure in the area is responsible for the oceanic winds which push any rain clouds away from the region without depositing rain. This lack of precipitation caused the formation of the Kalahari Desert, which lies mainly in Botswana, and has an arid mixture of grasslands and sand. When there is adequate rainfall (December - April are the months of rainfall), the grasslands provide excellent grazing for wildlife. Through preservation efforts and tourism, the Kalahari has become known for its game reserves and national parks. Tourism is more prevalent during the drier, cooler season of winter (June to August) because the animals are forced, as a result of the drought, to visit the riverbeds and watering holes.  

South of the Kalahari Desert, conditions are suitable for a variety of agricultural activities which include fruit orchards and an expanding wine industry. Although regions with Type C climates support larger farming operations, populations grow faster than increases in agricultural production leading to a depletion in natural resources.

Complete the review activity below.

Unlike other continents, Africa does not have extended mountain ranges comparable to the ranges of other continents. Instead, the continent of Africa consists of basins and plateaus. The Cameroon Highlands are a product of a geologic rift in tectonic plates that created the border between Nigeria and Cameroon. The only active volcano, Mt. Cameroon, rises to more than thirteen thousand feet making it the highest point in elevation for the region.

The only continuous features of the continent are the eastern rift valleys that run along the tectonic plate boundaries from the Red Sea to South Africa.

The Great Rift Valley 

The Great Rift Valley provides evidence of a split in the African Plate, dividing it into two smaller tectonic plates: the Somalian Plate and the Nubian Plate. The Great Rift Valley is divided into the Western Rift and the Eastern Rift. Mountain ranges in the Western Highlands of the Congo have a greater effect on climate than the two massive peaks in the east. On the western edge of the Western Rift are the highlands, which have a series of high-elevation mountain ranges, including the Rwenzori Mountains, which include active volcanoes. Various volcanoes in this range have active lava lakes in their craters. Reaching elevations of more than sixteen thousand feet, the Rwenzori Mountains on the Congo-Uganda border have permanent snow and glaciers. These ranges create a rain shadow effect that cuts off moisture for the region from the westerly equatorial winds. Recall that westerly winds are winds that travel from the west to the east.

Complete the activity below.

 

RESOURCES IN THIS MODULE ARE OPEN EDUCATIONAL RESOURCES (OER) OR CREATED BY GAVS UNLESS OTHERWISE NOTED. SOME IMAGES USED UNDER SUBSCRIPTION.