General Information

The largest desert in the world, the Sahara is a vast sun-baked world of barren rock, gravel, and shifting sand that stretches all across northern Africa. This enormous plot of land is almost as large as the whole United States, covering a grand total of more than 9,065,000 sq km. Fortunately, there is some respite for the dry landscape as the Sahara is dotted by some 207,200 sq km of partially fertile oases.

The great desert area extends from the Atlantic Ocean eastward to the Red Sea, about 1610 km from north to south and about 4830 km long from east to west. This vast area covers parts of Western Sahara, Mauritania, Morocco, Algeria, Tunisia, Mali, Niger, Chad, Libya, Egypt, and Sudan. The boundaries of the exact area not clearly defined and have been shifting for millennia. Over 8000 years ago, the Sahara was a fertile area where farmers were able to grow millet. Unfortunately, as conditions gradually became drier and desertification set in, the farmers abandoned their land.

The burning sun and scorching winds makes the Sahara the hottest region in the world in summer. The cloudless sky and dry air exposes the land to the piercing tropical sun. A sandy surface may have a temperature of 77 degrees Celsius or more. In July, the air temperature is more than 38 degrees Celsius in many places. However, the land cools rapidly when the sun sets- temperatures may drop to -1 to 10 degrees Celsius. In winter, they may fall below freezing in the north and form ice at night.

The Sahara is one of the Earth's low latitude deserts that extend inland from west coasts in and near the tropics. The dry winds that blow over the hot land seldom drop rain except where mountains force the air upward, cooling it. Elsewhere rain falls only when a powerful cyclonic storm invades the region, bringing a downpour. In some areas, such storms occur only once in ten or more years. Other then the Nile and the Niger rivers, which cross the edges of the Sahara, there are no other permanent streams. Dry streambeds, called wadis, seam the desert. They may fill with torrents of water during the rare downpours. As a result, travelers are warned against camping in them.

In the Sahara, various surface formations common to most deserts can be found. Flat dry land, called hamadas, broad stretches of gravel, and groups of sand dunes, called ergs are numerous. Though the dunes are the most picturesque feature, they occupy only about one eighth of the area. The Libyan Erg near Egypt holds the greatest mass of dunes on Earth, covering an area as large as France.

Although the Sahara is recognized as a single desert area, there are three geographically distinct areas within the region. The western Sahara (a.k.a. the Sahara proper) is an area of rock-strewn plains and sand deserts of varying elevation. The land is almost entirely without rainfall or surface water, but possesses a number of underground rivers. Occasionally the waters of these rivers find their way to the surface; in these naturally irrigated oases, plants grow freely. The soil of this region of the Sahara is fertile and, where irrigation is possible, produces excellent crops.

The central Ahaggar Mountains and the Tibesti massif, a plateau region, runs for approximately 1610 km in a northwestern to southeastern direction. The plateau itself varies in height from about 580 to 760 m, and peaks in the several mountain ranges that rise from the plateau. Although rainfall is scanty in the area, a number of the central peaks are snowcapped during part of the year.

The Libyan Desert in the east is considered the most arid part of the Sahara. Moisture is almost totally absent and few oases exist. Sandy wastes and large dunes of sand 122 m or more in height characterizes the land. Although the valley of the Nile River and the mountainous area of the Nubian Desert to the east of the Nile are geographically part of the Sahara, the irrigation afforded by the Nile transforms the desert into fertile agricultural land.

Vegetation & Wildlife

Except in the oases, the desert is almost completely barren. Only a few stunted, thorny shrubs grow in western Sahara. However, many dormant seed remain. Soon after the rare rains, a carpet of delicate, quick-blooming flowers is quick to spread. The chief trees of the oases are the date palm and a form of acacia.

Gazelle and antelope are found in many parts of the desert, as are jackal, fennec fox, badger, and hyena. Bright-colored lizards can also be found lying half-buried in the sand. However, the Libyan Desert is virtually devoid of any form of animal or vegetable life.

Formation

The Sahara was not always a parched desert as it is today. Throughout the Ice Age, the huge glaciers and icecaps of Europe pushed the zone of temperate climate southward. The Sahara was then rich grassland and hunting ground for prehistoric people. Relics of these people include stone tools and rock carvings on sheltered cliffs and walls of caves.

History

By early ancient times, the Sahara was as dry and hot as it is today. The vast desert long barred travel to central Africa. However, during the reign of the Roman Empire, people learned to use the camel for desert travel. People from the Mediterranean coast filtered southward. They improved irrigation systems and planted date palms. Arabs with long camel caravans crossed the Sahara to collect ivory and gold, skins and ostrich feathers, and black slaves from central Africa.

The spread of modern transportation was speeded up after World War II, when the French began exploring and developing the petroleum and gas resources of Algeria. Caravan trails were changed into roads covered with a tar that withstands the heat. Four such roads cross the desert from north to south. Airports were built at the chief oasis towns and at oil and gas fields. Pipelines were laid to carry the oil to Mediterranean ports. By the early 1960s, proven petroleum reserves in Algeria & Libya were estimated to be among the world's largest.

Life in the Sahara Today

Some of the people inhabit in the Sahara raise crops on irrigated land in an oasis. Others choose to tend flocks of goats, sheep, and camels along the desert's fringe or where sudden rains have fallen. These nomads wear long woolen robes called barracans, turbans and sandals for protection against the hot sun and stinging sandstorms. In the markets of the oasis villages they trade wool, hides, and some of their animals for dates, coffee, and manufactured articles.

Through the centuries palm-shaded oases have been ports of call for thirsty caravans. Here, they made stops to rest and pasture their camels. Many oases grew into fortified villages. The larger ones have a citylike appearance, with narrow, roofed-over streets and buildings several stories high. In recent years, gasoline stations and hotels have been built as well.