Biggest Deserts on Earth

What is a Desert? 

A desert is a landscape or region that receives very little precipitation - less than 250 mm per year (about ten inches). Approximately 1/3 of Earth's land surface is a desert. There are four different types of deserts based upon their geographic situation: 1) polar deserts; 2) subtropical deserts, 3) cold winter deserts, and 4) cool coastal deserts. As shown on the map above, deserts occur on all of Earth's continents.

The Largest Desert 

The two largest deserts on Earth are in the polar areas. The Antarctic Polar Desert covers the continent of Antarctica and has a size of about 5.5 million square miles. The second-largest desert is the Arctic Polar Desert. It extends over parts of Alaska, Canada, Greenland, Iceland, Norway, Sweden, Finland and Russia. It has a surface area of about 5.4 million square miles.

Non-Polar Deserts 

The rest of Earth's deserts are outside of the polar areas. The largest is the Sahara Desert , a subtropical desert in northern Africa. It covers a surface area of about 3.5 million square miles. A list of the twenty largest non-polar deserts can be found below.


The Desert Environment 

When most people think of a desert they imagine a landscape covered with sand and sand dunes. Although many deserts are sand-covered, most are not. Many desert landscapes are rocky surfaces. They are rocky because any sand-size or smaller particles on the surface are quickly blown away. Rocky deserts are barren wind-swept landscapes.

Most deserts receive so little precipitation that surface streams usually only flow immediately after rainfall - unless the stream has a source of water outside of the desert. Streams that enter a desert usually suffer major water losses before they exit. Some of the water is lost to evaporation. Some is lost to transpiration (taken up by plants and then released to the atmosphere from the plants). And, some is lost to infiltration (water soaking into the ground through the bottom of the stream channel).


Desert Fauna and Flora 

The plants and animals that live in a desert must be adapted to the environment. Plants must be very tolerant to intense sun, prolonged periods without precipitation and an ability to prevent moisture loss to conditions of severe temperature ranges, dry winds and low humidity.

Animals must be able to tolerate temperature extremes, temperature ranges and have an ability to survive with very little water. Many animals adapt to desert conditions by living underground and being active at night.

Major Deserts of the World
Name	Type of Desert	Surface Area	Location
Antarctic	Polar	5.5 million mi²	Antarctica
Arctic	Polar	5.4 million mi²	Alaska, Canada, Greenland, Iceland, Norway, Sweden, Finland, Russia
Sahara	Subtropical	3.5 million mi²	Northern Africa
Arabian	Subtropical	1 million mi²	Arabian Peninsula
Gobi	Cold Winter	500,000 mi²	China and Mongolia
Patagonian	Cold Winter	260,000 mi²	Argentina
Great Victoria	Subtropical	250,000 mi²	Australia
Kalahari	Subtropical	220,000 mi²	South Africa, Botswana, Namibia
Great Basin	Cold Winter	190,000 mi²	United States
Syrian	Subtropical	190,000 mi²	Syria, Iraq, Jordan, Saudi Arabia
Chihuahuan	Subtropical	175,000 mi²	Mexico
Great Sandy	Subtropical	150,000 mi²	Australia
Kara-Kum	Cold Winter	135,000 mi²	Uzbekistan, Turkmenistan
Colorado Plateau	Cold Winter	130,000 mi²	United States
Gibson	Subtropical	120,000 mi²	Australia
Sonoran	Subtropical	120,000 mi²	United States, Mexico
Kyzyl-Kum	Cold Winter	115,000 mi²	Uzbekistan, Turkmenistan, Kazakhstan
Taklamakan	Cold Winter	105,000 mi²	China
Iranian	Cold Winter	100,000 mi²	Iran
Thar	Subtropical	75,000 mi²	India, Pakistan
Simpson	Subtropical	56,000 mi²	Australia
Mojave	Subtropical	54,000 mi²	United States
Atacama	Cool Coastal	54,000 mi²	Chile
Namib	Cool Coastal	13,000 mi²	Angola, Namibia, South Africa