"Deserts are arid, barren regions deficient in moisture, plant and animal life."

The Light Brown Areas are Deserts

Deserts often generalised to be hot and sandy. However, this conception is not totally true, because not all deserts are hot and sandy. Deserts are distinguished to be areas with little water and generally inhospitable to life. Deserts have less than 250mm of rain per year. They also have a higher evaporation rate compared to rainfall. Most deserts are hot but come, like in the Tibetian regions, the land is 4000m above sea level and temperatures fluctuate around the freezing/melting point.

Deserts that are located in the temperate and polar regions have lower temperautes. For example, the semi-desert of Patagonia in South America has an average temperature of 7ºC throughout the year.

Temperatures change seasonally too. Deserts in the middle of continents, like some in Central Asia and USA, have bitterly cold winters as well as scrotching hot summers. This is varied against Sahara, a tropical desert, which experiences little temperature changes and is hot all throughout the year.

One fifth of the world's deserts are covered in sand. The giant waves of sand-dunes in the Rub al Khali (Empty Quarter) in Arabia are probably many people's image of a desert. However, most deserts are made up of stones, gravel and rock. For example, many parts of the Gobi Desert in north-west China have endless flat expanses of black and gray gravel with the occasional rock outcrop.

Despite their exotic appearances, deserts are the least welcoming habitats. Hence, due to the lack of water and vegetation, there are few animals and humans who live there. However, there are many varieties of desert plants and animals that have adapted to desert conditions. Humans have also used techonology to change conditions in deserts and made it more supportive of life.

	33.6% of the world arid/semi-arid 13% of world population live there	World's largest desert The Sahara, (area 9 million sq. km)
	Hottest temperature recorded 58 ºC at Al Aziziyah (Libya, Sahara)	World's driest place Arica, Chile - 0.8 mm rainfall per year.
	Hottest temperature recorded 58 ºC at Al Aziziyah (Libya, Sahara)	Longest drought Calama, Chile - 400 year until 1971