Deserts cover about one-fifth of all the land in the world. There are deserts in
parts of Africa, Asia, Australia and North and South America.
Most deserts lie along two imaginary lines north and south of the
equator, called the Tropic of Cancer and the Tropic of Capricorn. Here,
and in other desert regions, dry air currents blow across the land. These
dry air currents can blow hot or cold
but they rarely carry rainclouds.
Consequently the lands they cross are
starved of rain and given no protection
from the sun.
Some deserts are called rain shadow
deserts. These occur where large
mountains block the path of rain-bearing
wind. The raised mountain ground pushes
the wind upwards and as it rises, it cools.
The drop in temperature causes clouds
carried by the wind to burst and release
their rain. The wind continues over the
mountains but by the time it reaches the
other side, it carries no rain clouds. This
natural process creates some of the
world’s wettest environments –
rainforests – alongside the world’s driest.
The Sahara Desert in northern
Africa is the largest desert in the
world. It covers an area the size of the
• The Gobi Desert in eastern Asia is
situated on high, windy plains. It is the
coldest desert in the world.
• The Arabian desert is the sandiest
desert in the world.
• The smallest desert regions of the
world are the Peruvian and Atacama
Deserts on the western coast of South
• Many of the world’s deserts are
bordered by areas of scant vegetation.
These scrublands can become true
deserts if they lose