A Desert is large, extremely dry area of land with sparse vegetation.
More specifically, it is defined as an area that receives an average annual precipitation of less than 250 millimeters (10 inches).
Deserts cover about 33 percent, or one-third, of the Earth‘s total landmass.
There are four types of deserts:
• subtropical deserts are hot and dry year-round
• coastal deserts have cool winters and warm summers
• cold winter deserts have long, dry summers and cold winters with low rain or snowfall
• polar deserts are cold year-round
In terms of sheer size, the Antarctic Desert is the largest desert on Earth, measuring a total of 14.2 million square kilometers (5.5 million square miles). Antarctica is the coldest, windiest, and most isolated continent on Earth, and is considered a desert because its annual precipitation can be less than 51 millimeters (10 inches) in the interior.
The Arctic Desert is the second-largest desert in the world, covering a land surface of about 14 million square kilometers (5.4 million square miles). The desert partially occupies parts of territories claimed or controlled by Canada, Denmark, Norway, Russia, Sweden, and the United States.
The Sahara Desert is the third-largest desert in the world, and the world’s largest “hot desert.” It occupies a surface area of about 9.2 million square kilometers (3.3 million square miles). The Sahara covers large parts of Algeria, Chad, Egypt, Libya, Mauritania , Mali, Morocco, Niger, Western Sahara, Sudan and Tunisia.
The smallest desert in the world is the Atacama Desert, Chile, covers only 105,200 square kilometers (40,600 square miles).
Some deserts that are hot during the day become cold at night because they lack the insulation provided by clouds and humidity.
Deserts support a community of distinctive plants and animals specially adapted to the harsh environment.
Plant life in the desert is scarce, but there are more plants living here than you would expect. For example two of the most popular desert plants are the ocotillo which is a leafy green plant that produces flowers. The other one is the saguaro cactus which was named Arizona‘s state flower.
Animals find clever ways to adapt in deserts. Some are nocturnal, only coming out at night when it’s cool and others can go days without drinking.
Camels are one of the most recognizable of all desert animals. They have a great capacity to resist heat and thirst. Even above 50 C° (122 F°), they can stay without drinking water for many days.
A dune is a mound of sand this is formed by the wind, usually in a desert. Dunes form when wind blows sand into a sheltered area behind an obstacle.
Europe is the only continent without deserts; there are, however, semiarid portions around the Black and Caspian seas, in parts of Ukraine and the North Caucasus.
The words desert in English, désert in French, desierto in Spanish, and deserto in Italian all come from the Latin desertum, meaning “an unpopulated place.”
People have struggled to live in deserts and the surrounding semi-arid lands for millennia. Nomads have moved their flocks and herds to wherever grazing is available and oases have provided opportunities for a more settled way of life.
Around 2 million people live in the Sahara Desert.
Some of the world’s largest supplies of underground water exist beneath the Sahara Desert, supporting about 90 major oases there.
Death Valley is a desert valley located in Eastern California, in the northern Mojave Desert bordering the Great Basin Desert. It contains some of North America’s most inhospitable terrain, with extreme heat that has left this desert area strangely beautiful.
The Nazca Lines are a series of large ancient geoglyphs in the Nazca Desert, in southern Peru. The Nazca (or Nasca) civilization flourished in southern Peru between 200 BC and 500 AD. The Nazca Lines were made over many centuries and although their exact purpose is disputed the most widely held theory is that they were designed to be walked along as part of religious rites and processions.
Mars is the only other planet in the Solar System besides earth on which deserts have been identified.