Africa is called "tropical continent", and its climate is characterized by high temperature, little rain and dryness, and the distribution of climate zones is symmetrical from north to south. The equator passes through the center, and with the increase of latitude, the climate generally decreases from the equator. The area with annual average temperature above 20℃ accounts for about 95% of the whole continent.

More than half of the year is hot, and nearly half have hot and warm seasons and warm and cool seasons. Only the Lake Chad basin has a sound river system. Okavango River basin and Sahara desert are very dry, and there are many intermittent rivers and many dry valleys in the desert.

The precipitation in Africa decreases from the equator to the north and south sides, and the distribution of precipitation is extremely uneven. In some areas, there is almost no rain all year round, and in some places, the annual precipitation is as high as 10000 mm or more. The average annual precipitation in the whole continent13 is less than 200mm. There is more precipitation on the windward slope in the southeast, along the coast of the Gulf of Guinea and in mountainous areas.

I. Famine in Africa

Land drought and sand erosion caused by tropical climate and desert have reduced grain production or even failed to harvest, and hunger has long plagued Africa. Some people think that it is caused by the extreme population expansion in Africa, and the out-of-control population intensification has led to the emergence of food shortage crisis. Some people say that it is caused by the destruction of the ecological environment.

Second, the characteristic terrain

1. The most important terrain in Africa is the plateau. Except for the extreme northwest and south, the whole African continent can be regarded as a plateau, with an average elevation of 650m, slightly lower than that of the Asian continent; However, the vast plateau area is the highest of all continents.

2. Fault landforms are widely developed. The steep cliffs on the edge of the African continent are, of course, the product of the crustal fracture during Gondwana's split, and even those terraces that stretch for hundreds of kilometers and reach tens to hundreds of meters in West Africa are caused by the fracture. But the most developed area of fault topography is East Africa.

3. There are few folded mountains, which are distributed on the edge of the plateau. Most of the towering mountains on the African plateau are volcanic bodies. Only Mount Ruwenzori in East Africa is an exception. This is a big mountain.

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