Deserts of the World

One thing all deserts have in common is they are arid, or dry. Most experts agree a desert is an area of land receiving no more than ten inches of precipitation a year. The amount of evaporation in a desert often greatly exceeds the annual rainfall. In all deserts, there is little water available for plants and other organisms.
Deserts are found on every continent and cover about one-fifth of Earth's land area.