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What is a desert?
A desert, according to scientists, is
an area that has an average rainfall of less than ten inches in a
year. The classification covers both hot and cold deserts such as
Greenland, Antarctica and Northern Russia. There is a third type of
desert too, known as edaphic desert, wherein there is adequate
rainfall, but despite there being enough rainfall, the soil remains
too poor for trees and plants. A study says that hot deserts and
edaphic deserts cover eighteen per cent of the earth’s land surface
and cold deserts account for sixteen per cent. Or in other words,
deserts cover more than one-third of the earth’s land surface. |
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The driest spot
on the earth
The Atacama Desert in South America is considered the driest
spot on earth. It has been reported that parts of the Atacama
went without rain for over four hundred years, between 1570 and
1971. Fog clouds roll towards the Atacama Desert from the
Pacific Ocean at least sixty days in a year. This is the only
source of water to the area. However, these clouds do not have
much moisture and the area remains without water most of the
time. |
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Along the coast, the
aridity is also the result of the Humboldt or Peru Current, which
brings cold water from the Antarctic, causing a thermal inversion.
There is cold air at the surface of the ocean and stable, warmer air
higher up. This condition produces fog and stratus clouds but no
rain. Heavy rains fall in Iquique or Antofagasta only two to four
times a century. The average summer temperature in the region is
about 19°C.
Geographical features
Known in Spanish as Desierto De Atacama, it covers an area of
seventy thousand square miles (1,80,000 square kilometers) and forms
part of the Pacific coast of South America. It lies mainly in the
cool and arid region of Northern Chile, running a length of one
thousand or eleven hundred kilometers from north to south. It also
touches Peru and Bolivia.
The Atacama is
surrounded by a line of low coastal mountains, the Cordillera de la
Costa, on its west and to its east lies the Cordillera Domeyko,
foothills of the Andes. It consists mainly of salt pans at the foot
of the coastal mountains on the west and of alluvial fans sloping
from the Andean foothills to the east. Some of the fans are sandy
and covered with dunes. Pebble accumulations are very common.
Desert potato
Farming, to a small extent has been possible in the desert.
Lemons are grown at Pica, and other products are cultivated on the
shores of the salt marshes at San Pedro de Atacama. Potato is also
grown in some parts of the desert.
Mineral resources
The area is rich in nitrate deposits, particularly sodium
nitrate, which were found in the central depression and in several
basins of the coastal range. Mining was being systematically done
after the mid nineteenth century. Ports were built and railroads
were developed to further the cause of industrialization. Until the
early part of the twentieth century, Chile had world monopoly on
nitrate. There were times when 3,000,000 tons of nitrates have been
extracted and taxes on its export amounted to half the government's
revenues. Some sulphur is also mined in the high Cordillera. The
chief source of revenue, however, is copper, mined at Chuquicamata
in the Andes.
Fight for the land
Because of its rich nitrate deposits, Chile, Peru and Bolivia
fought for claim on the area. Much of the area originally belonged
to Bolivia and Peru, but the mining industry was controlled by
Chile. Chile emerged victorious in the War of the Pacific that was
fought between the three countries between 1879 and 1883. A treaty
drawn at the end of the war, known as the Treaty of Ancón, gave
Chile permanent ownership of the whole Pacific coastline. |
