Deserts cover about one-seventh of the earth’s land surface. Desert regions cover 35% of the earth’s surface. Deserts have been classified into sub-tropical desert, cold winter and the cool coastal deserts of the world. From the desert world map, it can be learned that Sub-tropical deserts lie between 15 and 30′ latitude. They are cantered along the Tropics of Cancer and Capricorn.
Deserts are landscape forms or regions that receive little precipitation. They are cold at night and since the desert air is dry it holds little moisture. Desert regions receive an average annual precipitation of less than 250 mm (10 inches). The deserts are further subdivided into semiarid, arid, extremely arid and rainless deserts based on the amount of total precipitation in a year.
The world desert map shows the worldwide distribution of hot and temperate deserts. A desert, despite being a vast area of land that is extremely dry with little or no vegetation, comprises of one of the major ecosystems on this planet. It supports a wide range of plant and animal species that are attuned to survive in the harsh conditions.
Nature has endowed desert vegetation with peculiar features to survive in desert climate. Some plant categories like Xerophytes do not have leaves, which help them reduce loss of water, while others have long roots (Phraetophytes) that help them fetch water from deep down the earth. Similarly, perennials and annuals have behavioural patterns that help them adapt to harsh conditions of the desert.
Although some definitions of world desert also include areas which are too cold to support any vegetation, such as frigid deserts, the world desert map on this page, however, shows the distribution of only those areas that are conventionally termed as hot desert and temperate deserts.
In case of Australia, more than half of the population is concentrated in only one sixth of the total area and two thirds of the population lives in state capitals, which are also the major sea ports. Australia has got one of the highest urbanised populations in the world. The transportation becomes difficult and costly in desert areas. In Australia, much of the goods between the cities are handled by costal shipping.
It is estimated that one fourth of the final cost of a commodity is that of transportation. In desert areas, the temperature range is also very extreme. In the Thar desert of Rajasthan the minimum temperature during winter goes into minus (3 to 4 degree Celsius) and the maximum during the summers to 50 degree Celsius).