The Sahara Desert is the world’s largest hot desert, located in North Africa.
Its surface area of 9,400,000 square kilometers (3,630,000 square miles) including the Libyan Desert and covers about 1/4 of the African continent.It is comparable to the respective land areas of China or the United States.
The Sahara is bordered by the Atlantic Ocean on the western edge, the Atlas Mountains and the Mediterranean Sea to the north, the Red Sea on the east, and the Sudan and the valley of the Niger River on the south.
The Sahara has one of the harshest climates in the world.
The Sahara is the world’s hottest desert.
The Sahara used to be a lush region with many plants and animals.It began to dry up around 4000 years ago due to a gradual change in the tilt of the Earth’s orbit.Earth’s obliquity oscillates between 22.1 and 24.5 degrees on a 41,000-year cycle. It is currently 23.44 degrees and decreasing.
The Sahara Desert is made up of sand dunes, sand seas, gravel plains, stone plateaus, salt flats, dry valleys, mountains, rivers, streams, and oases.
There is sparse grassland in some parts of the desert including the highlands and northern and southern parts of the desert.
The desert landforms of the Sahara are shaped by wind or by extremely rare rainfall and include sand dunes and dune fields or sand seas, stone plateaus, gravel plains, dry valleys, dry lakes and salt flats.Land formations change regularly.
Many of its sand dunes reach over 180 meters (590 feet) in height.
Several deeply dissected mountains and mountain ranges, many volcanic, rise from the desert.
Emi Koussi (huge extinct volcano), a peak in the Tibesti Mountains is 3,415 meters (11,204 feet) high and the highest point in the desert.
Snow may fall occasionally in some of the higher mountain ranges.On Feb. 18, 1979, low altitude areas of the Sahara desert recorded their first snowfall in living memory. Snow fell in spots in southern Algeria.It snowed in Algeria again in 2012.
Most of the rivers and streams in the Sahara desert are seasonal or intermittent, the main exception being the Nile River, which crosses the desert from its origins in central Africa to empty into the Mediterranean.
There are some 20 or more lakes in the Sahara.Most of these are saltwater lakes. Lake Chad is the only freshwater lake in the desert.
Some of the world’s largest supplies of underground water exist beneath the Sahara Desert, supporting about 90 major oases there.
Around two million people live in the Sahara Desert.
The people who live in the Sahara are mostly nomads. Nomads move from place to place.
Like all deserts, the Sahara harbors a relatively sparse community of wild plants, with the highest concentrations occurring along the northern and southern margins and near the oases and drainages.
It has imposed adaptations on the plants.
For instance, near wadis and oases, plants such as date palms, tamarisks and acacia put down long roots to reach life-sustaining water.
In the more arid areas, the seeds of flowering plants sprout quickly after a rain, putting down shallow roots, and completing their growing cycle and producing seeds in a matter of days, before the soil dries out. The new seeds may lie dormant in the dry soil for years, awaiting the next rainfall to repeat the cycle.
From the Mediterranean vegetation which covered the Sahara mountains before they became a desert, only laurel and cypress trees remain in the region near gueltas.
Across the central, most arid part of the Sahara, the plant community comprises perhaps 500 species, which is extremely low considering the huge extent of the area.
Date palm trees, introduced by Arabs, is requisite for the existence of humans in the oasis; dates are very energetic food, trunks are used to make beams, leaves are used to make baskets, ropes, mats and covers for huts,… its preserves fruit trees against the sun.
Camels are the main animal of the desert.They have a great capacity to resist heat and thirst. Even above 50°, they can stay without drinking water for many days.The camel is the favourite animal used by nomads.The second favorite animal for nomads in the Sahara desert is goat.
Several species of fox live in the Sahara, including the fennec fox, pale fox and Rüppell’s fox.
The addax, a large white antelope, can go nearly a year in the desert without drinking. The dorcas
gazelle is a north African gazelle that can also go for a long time without water. Other notable gazelles
include the rhim gazelle and dama gazelle.
The northwest African cheetah, also known as the Saharan cheetah, is a subspecies of cheetah found in the northwestern part of Africa (particularly the central western Sahara desert and the Sahel).
Other animals include the monitor lizards, deathstalker scorpions, sand vipers, hyrax and small populations of African wild dog, red-necked ostrich, secretary birds, Nubian bustards, various raptors…
There is also dung beetle which was a holy symbol to the ancient Egyptians and has some impressive adaptability.
Saharan rock art is a significant area of archaeological study focusing on the precious treasures carved or painted on the natural rocks found in the central Sahara desert. There are over three thousand sites discovered that have information about Saharan rock art.
There have been dinosaur fossils found in the Sahara Desert.
Daytime temperatures can reach 58°C (136°F), but freezing temperatures are not uncommon at night. Its temperature can become as low as -6°C (22°F).
Half of the Sahara receives less than 2 centimeters (0.79 inches) of rain per year, and the rest receives up to 10 centimeters (3.9 inches) per year.The rainfall happens very rarely, but when it does it is usually torrential when it occurs after long dry periods, which can last for years.
Sandstorms are very common in the desert.Brown clouds of sand cover the sky as wind blows sand everywhere.
The word “Sahara” means “desert” in the Arabic language.