More so than any other region of the world, the climates of the Middle East and Africa play an important role in human settlement and development. First, we will look at the extreme nature of the climate in the Middle East and then we will examine the variation of climates in Africa. As you can see in this map, the dominant climate of the Middle East is desert. As you might imagine, the extremely arid, or dry weather, poses many challenges to human settlement. As we have already established, water plays a pivotal role in food production and therefore where humans live. One of the best examples of this is found in Egypt, near the Nile River delta, where irrigated agriculture is possible. However, due to the harsh conditions of the Sahara desert, very few people live beyond the banks of the Nile. While the climate of the Middle East is primarily desert, the extreme differences in Africa’s climate make its environment much more complex.
As you can see, the African climate consists of everything from the driest conditions, the deserts, to the wettest, the rainforests. You may remember from the climate discussion how high and low pressure zones create differing environments. Recall that low pressure is associated with rising air and therefore, cloud development and rainfall; whereas high pressure is associated with sinking air and thus dry conditions. As this image illustrates, due to the fact that Africa straddles the equator, it has a relatively symmetrical climate. At the equator, low pressure dominates and this area is designated as rain forest. However, at approximately 20-30 degrees north and south latitude, the area is desert. Remember, at this latitude, high pressure dominates, thus the very dry conditions. Then, in between these extreme zones, you find the savanna and steppe climates. These climate types receive a moderate amount of precipitation and therefore, the dominant vegetation type is grassland.
One of the most productive regions in Africa is called the Sahel. The Sahel is a drought-prone savanna region just south of the Sahara desert. As we prepare to see an image showing vegetation in Africa, look for the effect that climate belts have on vegetation. Once again, you see the effects of the dry conditions to the north and south and the rainforest near the equator. Now that we have established that the savanna and steppe climates are located between the desert and rainforest, let’s go one step farther to understand the processes that create this environment. During the summer, the low-pressure zone responsible for the rainforest climate and the high-pressure zones responsible for the deserts, move slightly to the north. As the low-pressure belt moves over the Sahel, it brings rainfall. However, during the winter, these belts move in tandem to the south. Therefore, the Sahel is now dominated by high pressure. The areas of steppe and savanna, just to the south of the equator, experience the same seasonal rainfall and drought as the Sahel, just at opposite times of the year.
Notice on this infrared image, the cloud cover, or the lack thereof, over Africa: the east-west belt of clouds, created by low pressure, causes rainfall near the equator. You can also identify the high-pressure zones, just to the north and to the south of the equator, by the lack of clouds. The extreme environmental conditions in Africa have contributed to the lack of food production, and therefore development, on that continent. In the next section, Monsoon Asia, you will see where more favorable conditions have contributed to better food production, and therefore in increased development..