The Sahara Desert: Shifting

7 The Sahara Desert: Shifting“ Sandscape” Hot days with temperatures soaring above 40℃, nights of extreme cold, small bands of nomadic people travelling across a barren territory with only the stars to guide them. Welcome to the Sahara, the world's largest hot desert, covering more than nine million square kilometres across North Africa. The Sahara is a complex ecosystem bound by its dry, harsh climate. It is known as one of the toughest places on Earth. A mistake on the Sahara can cost you your life. People perish without water. You either carry enough water with you, or you know exactly where and how to find it. Any area of land where the annual rainfall is less than 250 mm is officially classified as a desert. It's the lack of water-not the sand-that makes a desert a desert. In fact, you might be surprised to learn that only 25 percent of the Sahara is covered with sand.

Although it occupies an area almost as big as Canada, the Sahara is one of the least populated places on Earth. Less than two and a half million people live there. Most of them are nomads-people with no permanent home. They are known as Bedouin, the Arabic word for " desert dwellers" . They are mostly descendants of Arabs who migrated west from their desert kingdoms. Everything they need for survival, they carry with them. These nomads live in small family groups and are constantly on the move. Age-old wisdom about how to live in the Sahara has been passed down from generation to generation. Often you can find Bedouin in places where water is abundant, and date trees provide shade and a welcome rest. Goats, sheep, and camels provide food and transport. It's hard to imagine, but the Sahara desert was once covered in ice during the last Ice Age. Thousands of years later, the ice melted, leaving fertile grasslands. Slowly, changes in the climate transformed the land from lush and tropical to the desert we know today. The story of the Sahara is indeed the story of shifting sands.