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By Amanda Briney
The
Sahara Desert is located in the northern portion of Africa and
covers over 3,500,000 square miles (9,000,000 sq km) or roughly 10% of the
continent.
It is
bounded in the east by the Red Sea and it stretches west to the Atlantic Ocean.
To the
north, the Sahara Desert's northern boundary is the Mediterranean
Sea, while in the south it ends at the Sahel, an area where the
desert landscape transforms into a semi-arid tropical savanna.
Since
the Sahara Desert makes up nearly 10% of the African continent, the Sahara is
often cited as the world's largest desert.
This is
not entirely true, however, as it is only the world's largest hot desert.
Based
on the definition of a desert as an area receiving less than 10 inches (250 mm)
of precipitation per year, the world's largest desert is actually the continent
of Antarctica.
Geography of the Sahara Desert
The Sahara covers parts of several African nations
including Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Sudan,
and Tunisia.
Most of the Sahara Desert is undeveloped and features
a varied topography.
Most of its landscape has been shaped over time by
wind and includes sand dunes, sand seas called ergs, barren stone plateaus,
gravel plains, dry valleys, and salt flats.
Around 25% of the desert is sand dunes, some of which
reach over 500 ft (152 m) in height.
There are also several mountain ranges within the
Sahara and many are volcanic.
The highest peak found in these mountains is Emi
Koussi, a shield volcano that rises to 11,204 ft (3,415 m).
It is a part of the Tibesti Range in northern Chad.
The lowest point in the Sahara Desert is in Egypt's Qattara Depression at -436
ft (-133 m) below sea level.
Most of the water found in the Sahara today is in the
form of seasonal or intermittent streams.
The only permanent river in the desert is the Nile
River that flows from Central Africa to the Mediterranean Sea.
Other water in the Sahara is found in underground
aquifers and in areas where this water reaches the surface, there are oases and
sometimes small towns or settlements like the Bahariya Oasis in Egypt and
Ghardaïa in Algeria.
Since the amount of water and topography varies based
on location, the Sahara Desert is divided into different geographic zones.
The center of the desert is considered hyper-arid and
has little to no vegetation, while the northern and southern portions have
sparse grasslands, desert shrub and sometimes trees in areas with more
moisture.
Climate of the Sahara Desert
Although hot and extremely dry today, it is believed
that the Sahara Desert has undergone various climatic shifts for the last few
hundred thousand years.
For example, during the last glaciation, it was bigger
than it is today because precipitation in the area was low.
But from 8000 BCE to 6000 BCE, precipitation in the
desert increased because of the development of low pressure over ice sheets to
its north.
Once these ice sheets melted, however, the low
pressure shifted and the northern Sahara dried out but the south continued to
receive moisture due to the presence of a monsoon.
Around 3400 BCE, the monsoon moved south to where it
is today and the desert again dried out to the state it is in today.
In addition, the presence of the Intertropical
Convergence Zone, ITCZ, in the southern Sahara Desert prevents moisture from
reaching the area, while storms north of the desert stop before reaching it as
well.
As a result, the annual rainfall in the Sahara is
below 2.5 cm (25 mm) per year.
In addition to being extremely dry, the Sahara is also
one of the hottest regions in the world.
The average annual temperature for the desert is 86°F
(30°C) but during the hottest months temperatures can exceed 122°F (50°C), with
the highest temperature ever recorded at 136°F (58°C) in Aziziyah, Libya.
Plants and Animals of the Sahara Desert
Due to the high temperatures and arid conditions of
the Sahara Desert, the plant life in the Sahara Desert is sparse and includes
only around 500 species.
These consist mainly of drought and heat resistant
varieties and those adapted to salty conditions (halophytes) where there is
sufficient moisture.
The harsh conditions found in the Sahara Desert have
also played a role in the presence of animal life in the Sahara Desert.
In the central and driest part of the desert, there
are around 70 different animal species, 20 of which are large mammals like the
spotted hyena.
Other mammals include the gerbil, sand fox, and Cape
hare. Reptiles like the sand viper and the monitor lizard are present in the
Sahara as well.
People of the Sahara Desert
It is believed that people have inhabited the Sahara
Desert since 6000 BCE and earlier.
Since then, Egyptians, Phoenicians, Greeks, and
Europeans have been among the peoples in the area.
Today the Sahara's population is around 4 million with
the majority of the people living in Algeria, Egypt, Libya, Mauritania, and
Western Sahara.
Most of the people living in the Sahara today do not
live in cities; instead, they are nomads who move from region to region
throughout the desert.
Because of this, there are many different nationalities
and languages in the region but Arabic is most widely spoken.
For those who do live in cities or villages on fertile
oases, crops and the mining of minerals like iron ore (in Algeria and
Mauritania) and copper (in Mauritania) are important industries that have
allowed population centers to grow.
Amanda Briney
Geography Expert
Education
M.A., Geography, California State
University - East Bay
B.A., English and Geography, California
State University - Sacramento
Introduction
Professional geographer, writer, and
scholar
Certificate of Advanced Study in
Geographic Information Systems (GIS)
More than 10 years of experience writing
about a broad array of geographical topics
Experience
Amanda Briney is a professional
geographer and writer who contributed to ThoughtCo for more than 10 years. She
wrote countless articles on a wide range of topics such as an introduction to
the subject of geography, reviews of ecotourism, discussions about
environmental determinism, and the structure of Latin American cities. The
scope of her work also includes other formats such as histories, guides, and
fact sheets about many parts of the world. An ultimate scholar, Amanda also
contributes work to academic venues and the GIS Lounge, an informational portal
about geography.
Amanda enjoys all aspects of geography
and mapping but is especially interested in examining natural landscapes
through spatial analysis. As such, she holds a certificate in Geographic
Information Systems (GIS) from California State University. She also attended
Diablo Valley College where she studied air photo interpretation and the
formation of the Earth's landscapes.
Education
Amanda Briney received a Master Arts
(M.A.) in Geography from California State University–East Bay. She also holds a
Bachelor Arts (B.A.) in English and Geography from California State
University–Sacramento and earned a Certificate of Advanced Study in Geographic
Information Systems (GIS) from California State University.
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