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THE SAHARA DESERT
The Sahara is the biggest desert on earth. In fact, it is as large as Europe and larger than the combined area of the next nine largest deserts in the world.
Did you know that once upon a time, elephants, giraffes and buffalo roamed its vast expanses? Unbelievable as it may seem, but the Sahara was once a green and well-watered area. Of course, that was some 30 or 40 thousand years ago!
But then the Sahara became warmer as much of the ice that covered parts of Europe receded northward. As a result, the rivers dried up; the rain became less. Gradually the great expanse turned into one of the most forbidding areas in the world — an endless stretch of sand blistered by the sun in the day, and icy cold at night.
The extreme fluctuation in the day and night temperatures have made the Sahara a desert. It is also one of the hottest regions in the world. The fierce heat in the daytime makes the rocks expand, while the sharp drop in temperature at night and the constant evaporation make them crack. The strong winds grind the fragments together, making sand.
Rainfall is generally very low. Sometimes rain starts falling and due to the intense heat evaporates before reaching the ground. Some years are even rainless. Wherever water can be found at or near the surface, oases are found. Here, date palms flourish. A lush oasis offers welcome shade from the scorching desert sun.
There are three main types of scenery in the Sahara: the erg, desert with shifting sand dunes; the reg, rocky plains; and the hammada, bare plateaux.
The world’s largest deserts include: Sahara of North Africa (9,065,000 sq km.), Gobi Desert of Mongolia-China (1,295,000 sq km.), the Kalahari of Southern Africa (582,000 sq km.), and Great Victoria located in Australia, covering an area of 338,500 sq km.
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