 You are clear for launch. And with that, shut down your visors, O2 on, and prepare for ignition to O2. You can copy that and... Mr. Ruchoff here. Alright, so in this lesson, we're going to move down south of the Sahara into the heart of Africa. More specifically, we're going to look at the physical geography of sub-Saharan Africa. Now, we need to realize that Africa is a huge, huge continent. After Asia, it is the largest continent in the world, covering over one-third of the world's surface area. And the term sub-Saharan Africa means below the Sahara Desert, and the region we first come to is the Sahel. The Sahel is a semi-arid transitional zone between the Sahara Desert to the north and the savannas to the south. The Sahel will receive less than 20 inches of rain during the year. Now, fortunately for the people of Western Africa, the Niger River flows through the region to provide needed water. Now, another body of water in the Sahel is Lake Chad. Unfortunately, between 1963 and 1998, Lake Chad lost about 95% of its water. Just like the Aral Sea, this is a result of the diverting of water for irrigation and the desertification we see within the Sahel. Now, providing water to the people of the east is the Nile River, which is the longest river in the world. And the Nile has two tributaries that feeds into it. The Blue Nile comes out of the Ethiopian highlands, and the White Nile comes out of Lake Victoria. Both these tributaries come to Khartoum Sudan and combine to become the Nile River flowing into the Mediterranean Sea. And like we said, one of the sources of the Nile is the Ethiopian highlands that feeds into the Blue Nile. These mountains are over 14,000 feet and are known as the Roof of Africa. Now, running right through the Ethiopian highlands is something known as the Great Rift Valley. Now, a Rift Valley is created whenever you have tectonic plates that are diverging. As the plates pull away from each other, the land in the middle may drop down in creating a valley. The Great Rift Valley in Africa is a Y-shaped valley that was created when the Somalia plate pulls away from the Nubian or the African plate. Now, the separated plates means that the crust in between is under less pressure. This lowers the melting temperature of the rock, and as it melts, lava will corrupt and it will come through the cracks in the ground. This also creates volcanoes. The group of volcanoes created by the Rift Valley are known as the Eastern Rift Mountains. Now, all volcanoes are divided into three groups. You have active, dormant, and extinct. An active volcano means that there has been an eruption in the last 10,000 years, and geologists pretty much know that it will erupt sometime in the future. Now, geologists also believe that dormant volcanoes will erupt in the future, but they haven't done so in the last 10,000 years. They pretty much just sleeping. And extinct volcanoes are those that geologists believe will never erupt again. Now, it's in the Eastern Rift Mountains we find the two tallest mountains in Africa. The first is Mount Kilimanjaro, which over 19,000 feet is the highest point in Africa. Now, this is a dormant volcano with its last major eruption about 360,000 years ago. Now, Mount Kenya is the second tallest mountain in Africa, and while it is a volcano, is it extinct? It is not expected to ever erupt again. Another feature of a Rift Valley is that it creates very, very deep lakes. Essentially, the valley that is created as the diverging plates separate will fill up with water creating these lakes. In the Great Rift Region, we find three major lakes, Lake Victoria, Lake Tanganyika, and Lake Malawi. Lake Victoria is the second largest lake in the world if we're looking at surface area. It is also the source of the white Nile, which is the second of the Nile's tributaries that we previously discussed. Now, just to the west of Lake Victoria, we find Lake Tanganyika, which is the second deepest lake in the world at about 4,500 feet or just under a mile deep. It also is the lake with the second most volume of any lake in the world. It is also the second oldest lake in the world. Lake Baikal leads Lake Tanganyika in each of these other three categories. And to the south of Lake Tanganyika, we find Lake Malawi, which is Africa's third largest lake. It is also a rather deep lake at about 24 feet deep. But what is special about Lake Malawi is that it has more species of fish in its water than in the other lake in the world. There are over 1,000 identified species of fish in the lake and more are being identified pretty much every year. Some biologists estimate that there is actually up to 2,000 different species of fish. Another thing that is interesting about the lakes of the Rift Valley is that many of these lakes are what we call soda lakes. Due to the volcanic activity, volcanic chemical deposits make the lakes poisonous to humans. However, other animals can thrive in these lakes. For example, red algae, which flamingos will eat. Now what a lot of people don't realize is that flamingos are actually born either white or gray. It is the betel keratin in this red algae that actually turns flamingos pink. So let's take a moment to look at the climate of Africa. Now we've already seen it in the north that Africa is dominated by an air climate in the Sahara Desert and the Sahel has a semi-air climate. In the center of the continent, we find the tropical climates of tropical wet, tropical monsoon, and tropical wet dry. By the way, tropical monsoon climate is the same thing as a tropical wet dry, but it has a longer wet season. Now one of the types of grasslands we find in Africa is the steppe, which we find in this semi-air climate such as in the Sahel. These grasslands are similar to the grasslands we find in America's Great Plains, but then there is the savanna, which we find in the tropical wet-dry regions of eastern Africa. Now, although the annual rainfall of a tropical wet climate is actually much more than we might have here in Bryant, Texas, because it has a long dry season, a savanna does not have forests. It is basically a grassland with maybe some isolated trees. It is in the savannas such as in Serengeti or the Norgoregore crater showing these pictures that I took on my trip to Tanzania. We find elephants, ostriches, lions, wildebeests, and even giraffes. However, if we move directly west, we find the climate and the biome changes drastically as we move from a tropical wet-dry climate to a tropical wet climate of the Congo River Valley. The Congo River is Africa's second largest river system, and the Congo tropical rainforest is the second largest rainforest in the world after South America's Amazon. Now elsewhere, we find that vast areas of Africa are plateaus, which are separated by something known as escarpments. Escarpments are long, steep slopes that separate areas of land at different heights, and as you might imagine, this might interfere with land travel. But these escarpments create problems for river transportation in Africa as well. If a river flows over one of these escarpments, then a type of waterfall called in a cataract is called that has a steep surface that can be very wide. So while escarpments hinders land travel, cataracts hinders river transportation in Africa. It is on the Zambeze River that we find the biggest of these cataracts. See, the Zambeze River is in the southern portion of Africa and it flows eastward into the Indian Ocean. However, on this river we find Victoria Falls, which at over a mile wide is the widest waterfall in the world. Victoria Falls is also twice as tall as Niagara Falls is that sits in between the United States and Canada. This means a great amount of water flows over the falls every second. In fact, almost one million gallons of water flows over every three seconds. As we move further south, we leave the tropical climates and once again, we find ourselves in the arid and semi-arid areas of Africa. Now speaking of arid climates, one of the most interesting deserts is the Namib Desert, which sits right on the coast of the Atlantic Ocean. Now just like the Atacama Desert in South America, this desert is caused by the cool ocean currents to the Bengala current that passes right by it. Cool oceans don't evaporate very easily and if you don't have an evaporation, you don't have humidity. Without humidity, you don't have clouds. Without clouds, you don't have rain. In fact, the western edge of the Namib Desert near the Atlantic Ocean only receives about a fifth of an inch of rain every year. Now as we move eastward into the interior of the southern portion of Africa, we find ourselves in the Kalahari Desert. The Kalahari Desert spans over an area that has both semi-arid and arid climate. And it is in this desert we find the Saan tribes or the Bushmen. The Saan, who are a collection of different tribes that lives in the Kalahari, is the oldest culture in the world. Their culture in the region goes back some 40,000 years and some scientists actually think that it actually goes back as far as 100,000 years. And then as we continue moving southwest, we find the Drachenberg Mountains. Now these were named by the Dutch who settled into the area around the 17th century and their name actually means Dragon Mountains and they go up to about 11,000 feet. Now it is in these mountains that archaeologists have found paintings that the Saan painted some 35,000 to 40,000 years ago. So under these landforms, what resources do we find in Africa? Well, the answer is plenty. Oil is an important resource in several African countries, in fact both Nigeria and Angola are actually members of OPEC. Like diamonds, well, look nowhere else. The countries in Africa produce half of all the diamonds in the world. And in the south, there's gold. Several African countries are producers of gold, but none are so big as South Africa, which currently produces about one eighth of the gold produced in the world. And back in the 1990s, South Africa was actually producing about 30% of the world's gold. Something else Africa has a lot of is endangered animals. Animals such as elephants, black rhinos, and mountain gorillas are all endangered and face extinction. Now there are two major reasons for this. First, these animals are losing their habitat to either desertification, which we'll talk about in a few moments, and due to human settlement. The second reason is poaching, which is the illegal hunting of protected animals. Ivory from elephants or horns from rhinos command very high prices around the world. Now to combat these, there are three things that African countries are doing in order to protect their animals. The first thing that many countries are doing are establishing national parks in order to protect animals' habitat. One such example is in the Gorogor Crater in Tanzania. The second step is ecotourism. When I went to Tanzania in 2011, I had to pay our tour guide money. Part of what I paid our tour guide went to the government to be able to fund the conservation efforts of these national parks. And the third step is the enforcement of strict penalties for poaching, where that is fines or even prison time for poachers who are caught. Now another environmental problem in Africa is desertification. Desertification is when irritable land, this is land that you can farm on, is becoming a desert. Now there are four major reasons that causes desertification, what I call the four overs. The first reason is overplanting. When farmers do not use crop rotation or other techniques, the plants they raise strip the nutrients out of the ground and soon the ground cannot support any plants or crops. Without plants, the roots no longer hold the soil together and winter erosion picks up the soil and carries it away. The second reason is overgrazing by livestock. If livestock such as cows or goats are allowed to be in the same area too long, they will eat up all the plants. No plants means no roots, no roots means nothing to hold the soil together and the winter erosion will come and it will take the soil away. The third thing is overcutting. When people begin to cut down trees, whether it has fur lumber or fur firewood, we once again we lose plants in the roots that holds the soil together. And the last is overpopulation. With the growing African population, people need more and more water. In fact Cape Town, South Africa almost completely ran out of water a couple years ago. This often means that more water has to be diverted from flowing into the lakes and you have the situation we find in late Chad in which it has lost 95% of its water volume. Now each of these factors contributes to desertification, but there are things we can do. This includes crop rotation, would allow for the soil to continue to maintain its fertility and be able to produce crops and plants. Terracing of land can also prevent water erosion from taking that fertile topsoil away and planting in tree belts around farms will be able to block the wind and reduce wind erosion. Alright, so we've taken a look at the physical geography of sub-Saharan Africa. In our next lesson, we'll start looking at the people of the region. But until then, keep on learning.