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The 10 Largest Deserts In The World

Deserts are usually considered to be hot, arid areas with vast stretches of sand and dry earth. While this is certainly the case for some regions, all do not fit this description. Precipitation, not sand and heat, determine what areas are deserts. Deserts are found in all continents of the world but the nature and size of these deserts vary greatly. Since deserts are associated with difficult living conditions, they are often some of the world's most sparsely populated regions. In this article, we explore the world's largest deserts. 

The 10 largest deserts in the world are

• Antarctic - 5.5 million square miles
• Arctic - 5.4 million square miles
• Sahara - 3.5 million square miles 
• Arabian - 1.0 million square miles 
• Gobi - 0.5 million square miles 
• Patagonian - 0.26 million square miles
• Great Victoria - 0.25 million square miles
• Kalahari - 0.22 million square miles
• Great Basin - 0.19 million square miles
• Syrian - 0.19 million square miles

Some interesting facts about these deserts are mentioned below:

1. Antarctic - 5.5 million square miles

The Antarctic is classified as a polar desert. Measuring 5.5 million square miles (14.2 million sq. km), it is the largest desert in the world. Unlike most global deserts, the Antarctic covers the entire continent. In fact, an astonishing 98 percent is permanently covered by a sheet of ice. It is considered a desert because it rains on average only 10 mm every year. Some experts even believe that certain parts located away from the coast have not had rain in the past 14 million years.

2. Arctic - 5.4 million square miles

The Arctic tundra is the only other polar desert in the world. It spans numerous northern countries, including Canada , Greenland , and Russia . It is second only to the Antarctic, measuring a whopping 5.4 million square miles (13.9 million sq. km). It is also considered a desert due to the lack of precipitation; the frigid air is too cold to hold moisture. While it gets more rain than the Antarctic, it still only receives approximately six to ten inches a year.   

3. Sahara - 3.5 million square miles 

The Sahara is the largest subtropical desert in the world, clocking in at 3.5 million square miles (9 million sq. km). Spanning eleven countries, it covers nearly an entire third of Africa. It is most known for its scorching hot climate and mountainous sand dunes that reach as high as 183 meters. Despite these harsh conditions, it is home to numerous desert animals, including camels, lizards, and scorpions. Water sources are rare, but the Sahara does have two rivers and twenty seasonal lakes.

4. Arabian - 1.0 million square miles 

The Arabian is the world’s second largest subtropical desert. Spanning most of the Arabian Peninsula in Asia, it measures approximately 1.0 million square miles (2.6 million sq. km). It is a barren and sandy landscape, but is surprisingly rich in natural resources, such as oil and sulfur. Summer temperatures can go as high as fifty degrees Celsius during the day, but drop drastically at night. Locust and dung beetles are native to this bleak region.

5. Gobi - 0.5 million square miles 

The Gobi Desert is the fifth largest desert in the world. Spanning parts of Mongolia and China , it measures 0.5 million square miles (1.3 million sq. km). Its terrain is mostly rocks and hard-packed earth, which made it a valuable trade route throughout history. Like all traditional semiarid deserts, the Gobi experiences extremely high temperatures during the summer and frigid temperatures during the winter. It is also considered a rain shadow desert because the Himalayas block out all rainy weather.

6. Patagonian - 0.26 million square miles

Located in Argentina , the Patagonian Desert—also known as the Patagonian Steppe—is the sixth largest desert in the world. It measures roughly 0.26 million square miles (0.67 million sq. km). To the west lie the Andes, the world’s longest mountain range, and to the east, the Atlantic Ocean. As a semiarid desert, it shares similar characteristics with the Gobi desert. Frost covers the ground during the winter season, but snow is unusual due to the dryness of the region.

7. Great Victoria - 0.25 million square miles

The Great Victoria is a subtropical desert located in Australia . It is the seventh largest desert in the world, clocking in at 0.25 million square miles (0.65 million sq. km). It is a harsh environment of sand, rocks, hard packed-earth, and grassland. During the summer, temperatures rise up to forty degrees Celsius. As with most subtropical deserts, it is cooler during the winter, but still fairly hot. The Great Victoria receives an average of eight to ten inches of rain every year.

8. Kalahari - 0.22 million square miles

The Kalahari is a subtropical desert located in southern Africa. Spanning parts of Namibia , Botswana , and South Africa , it is the eighth largest desert in the world at 0.22 million square miles (0.56 million sq. km). Interestingly, it is classified as a semi-desert as it receives four to eight inches of rain per year, but twenty during special wet years—ten more than what is generally accepted for a region to be considered a desert. Wild animals such as meerkat, hyena, kudu, and wildebeest call this region home.

9. Great Basin - 0.19 million square miles

At 0.19 million square miles (0.49 million sq. km), the Great Basin is one of the “big four” deserts in North America. It spans multiple states, covering most of Nevada and Utah . Located directly north of the Mojave Desert , it is a dry expanse of clay, silt, and sand; however, as a semiarid desert, it receives a fair amount of snow during the winter months. It is said that at 4,950 years old, a local Bristlecone Pine is the world’s oldest living thing.

9. Syrian - 0.19 million square miles

The Syrian—also known as the Syrian or Jordanian Steppe—is the tenth largest desert in the world, measuring approximately 0.19 million square miles (0.49 million sq. km). It spans multiple Middle Eastern countries, including Syria , Jordan , Saudi Arabia , and Iraq . Despite its name, it covers more of Jordan than Syria. As a subtropical desert, it is a barren landscape of rock and gravel. What wildlife is able to thrive in such an environment is currently under threat from drought, over-grazing, and hunting.

The Effects Of Climate Change On Desertification

Human-made climate change is having a severe impact on our global deserts. It is common knowledge that the melting ice caps are shrinking the polar deserts, but global warming is also leading to higher rates of desertification—the process where fertile land becomes dry and arid. Pollution and other human activities are creating droughts and wildfires, and increasing levels of salt in the ground, which is ultimately causing subtropical and semiarid desert regions to expand and rise in temperature. Just like polar bears, this is also negatively impacting the local wildlife. Even animals such as lizards who normally thrive in these types of hot environments are struggling with desertification.

The Sahara is the best example to illustrate the above. A study conducted in 2018 shows that it has grown by ten percent since 1920. Deserts generally increase in size during dry seasons and decrease during wet seasons, but humans are interfering with this natural cycle, causing deserts to grow faster than they are shrinking. In fact, an entire third of the Sahara’s current size is due to climate change. Approximately 33 percent of the Earth’s land is covered by desert. Unless we change our ways, this number could increase drastically throughout the coming years.

The Largest Deserts In The World

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How Extreme Temperature Swings in Deserts Stir Sand and Dust

Understanding the movement of particles, some of which enter the atmosphere, may help scientists improve climate models and forecast dust storms on Mars

Richard Kemeny

The White Sands Dune Field is desolate and isolated, far removed from any human activity, traits that made the New Mexico desert an ideal spot for the U.S military to test the world’s first atomic bomb in 1945. It still serves today as an active missile range. The 275-square-mile expanse of white, gypsum sands also provide an ideal place for geomorphologist Andrew Gunn to conduct an unprecedented field experiment.

Able to work in peace, and without concerns of losing his expensive equipment to thieves, Gunn and his colleagues were trying to uncover the secrets of how sand moved. More specifically, they were studying whether daily temperature and wind changes in the Earth’s atmosphere led to predictable movements of sand and dust below. Determining a cause and effect at this patch of desert would be a key step in forecasting how particles at the planet’s surface influence the weather.

“The dune field is very strange, kind of inhospitable,” says Gunn. “It feels alien.”

Geomorphology, which Gunn studies at the University of Pennsylvania, looks at the way ice, water and air mold and transform the Earth’s landscapes. At White Sands, where temperatures can shift from -19 degrees Fahrenheit at night to 95 degrees during the day, Gunn discovered that the environment’s extreme temperature swings generate powerful winds that move dunes and pump dust into the atmosphere. The finding, published in Geophysical Research Letters earlier this year , will help scientists understand both how to build climate models here on Earth and how atmospheric processes may have shaped the surface of Mars.

Deserts cover roughly one-third of Earth’s terrestrial surface and are a critical part of the climate system . When sand turns to dust, winds or storms lift it into the atmosphere where it joins a global sediment circulation system that provides nutrients to phytoplankton in the ocean , feeds plant-life in the Amazon and even affects the formation of clouds. Several studies have explored how large weather events like thunderstorms and haboobs carry dust into the system, yet studies of how normal daily atmospheric changes affect the movement of sediment are less common.

Gunn and his team headed out to White Sands in the springs of 2017 and 2018—the windy season—armed with a hypothesis and a collection of gizmos to test it. The scientists thought that as the Earth’s surface and lower atmosphere became warmer than the air above, this would create winds that would move the sand. The researchers used a doppler lidar machine to scatter lasers into the air to measure winds roughly 1000 feet above the surface. They used a solar-powered tower with sensors, called a meteorological mast, to record heat and moisture. A sand saltation sensor detected when even a single grain of sand moved. And back in the lab, they analyzed satellite images using a machine-learning algorithm to measure dust entering the atmosphere.

They found that in the morning, sunlight heats the ground, which heats the lower atmosphere to the point that it becomes unstable and begins to convect—with hot, less-dense air rising and cooler, and denser air sinking. This convection stirs up the atmosphere and eventually drags a stream of fast-moving higher winds down to the ground.

“The idea is, basically, that dune fields create their own wind,” says Gunn.

Around noon, as surface temperatures peaked, the team discovered wind speeds reached their highest speeds while humidity in the sand had evaporated. Sand grains skipped along the surface, and dust moved up into the atmosphere. After sunset, the temperature of the air and sand dropped quickly. Wind speeds at the surface died down and the sand grains settled. Every day, the process repeated, with the desert moving a little and pumping more dust into the atmosphere.

“The transport of sand, the movement of the dunes, the emission of dust from the landscape—that is all intrinsically tied to this daily cycle,” says Gunn.

After the study at White Sands, Gunn and colleagues looked at meteorological observations taken over a decade from 45 dune fields around the world to see if they could find evidence of the same process. The findings mirrored those at White Sands. The higher the change in temperatures, the faster the winds generated at the surface of the desert.

Unexpectedly, they found that the size of the desert influenced the strength of the wind. The larger the dune field, the stronger the link between temperature shifts and wind speeds, and sand transport along the ground and into the atmosphere.

The discovery of this daily cycle of heat and the transport of sand and dust could improve climate modeling says Doug Jerolmack, an experimental geophysicist at the University of Pennsylvania and an author on the study. These models, which use dust emission data to predict cloud formation, are helpful for climate physicists and meteorologists in making accurate climate predictions. Clouds play an important and complex role in regulating the temperature of Earth’s climate, yet are difficult to model. Better data on dust could help researchers understand more about how clouds form, grow and interact with each other.

“There are a variety of things that water condenses around to make clouds, but the two major ones are dust and sea salt,” Jerolmack says. “This convective instability in the desert is now like a vertical pump, that is taking the dust and delivering it to the upper atmosphere where it can seed clouds.”

Lori Fenton , a planetary scientist at SETI Institute not involved with the study, says the same process observed at White Sands is likely to happen on Mars, perhaps with even stronger temperature and humidity swings. “On Mars, the dune sand is darker than the surrounding terrain, which would further enhance the convective instability that forms wind gusts,” she says.

Until relatively recently, scientists thought sand dunes on Mars were stationary relics from a former age. Yet ripples and dunes shown to be moving on the red planet suggest certain areas, such as Nili Patera dune field, Styrtis Major and Mawrth Vallis , are being moved by the current climate .

Martian dust storms, which start local and sometimes combine to envelope the whole planet, might be partially explained by Gunn’s findings too, as the atmospheric mechanics discovered at White Sands could be what kicks off the initial dust that creates local storms. “The formation of big planet-scale dust storms are an unsolved mystery in Mars science,” says Fenton.

NASA’s Perseverance, now roving along the surface of Mars, is expected to cross sand dunes and large ripples along its traverse of Jezero Crater to the edge of an ancient river delta. Its onboard sensors will be picking up meteorological data on surface temperature, wind profiles and dust particles—similar to Gunn’s experiment at White Sands. This will help confirm if intense heating is driving higher wind speeds on the Red Planet.

Getting accurate predictions of dust movement on Mars is important for practical reasons, too. In 2018, when NASA’s Curiosity rover got caught in a dust storm, it could no longer recharge its battery. “As we plan to send more equipment and eventually people to Mars, you want to have a good understanding of the wind regime,” says Jean-Philippe Avouac , a geologist and planetary scientist at CalTech. “If there's a lot of sand blown by the wind it’s going to damage all the equipment and that would be a major issue.”

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ENCYCLOPEDIC ENTRY

Not all deserts are sandy.

Deserts are landscapes that receive little precipitation. They can be hot and sandy like the Sahara, or cold and ice-covered like Antarctica.

Earth Science, Climatology, Geography, Physical Geography

Vegetation in the Sahara

The Sahara Desert's vast, harsh landscape is home to little life, but hardy animals and vegetation can be found in sparse pockets like the Merzouga oasis in Morocco.

Photograph by Dea/ A. Garozzo/ Contributor 

Sandy. Dry. Hot. These are the words typically used to describe the desert. But the endless, windswept dunes that come to mind only make up a small percentage of the deserts on the planet. A desert is actually just a place that has very little precipitation.

Subtropical deserts like the Sahara are what people generally imagine when they think about the desert. The Sahara has rocky plateaus as well as sand dunes . During the summer, the temperature in the Sahara can reach over 50°C (122°F), making it one of the hottest deserts on Earth. Despite these temperatures, the Sahara is home to olive trees, antelope , jerboa , scorpions , jackals, and hyenas . It is even home to some people, with several major cities located there, including Egypt’s Cairo, Libya’s Tripoli, and Mali’s Timbuktu. At 9.4 million square kilometers (3.6 million square miles), the Sahara is also the largest hot desert on Earth.

The largest desert on Earth is Antarctica, which covers 14.2 million square kilometers (5.5 million square miles). It is also the coldest desert on Earth, even colder than the planet’s other polar desert, the Arctic. Composed of mostly ice flats, Antarctica has reached temperatures as low as -89°C (-128.2°F). The ice that covers the area is on average 2.45 kilometers (1.5 miles) thick. There is almost no vegetation in Antarctica, so the animals that live there are mostly carnivores, such as penguins, albatrosses, whales, and seals. Antarctica’s waters are abundant with sea life, including fish, krill, and sea sponges.

How can both the Sahara and Antarctica be deserts? The reason is that they both see little precipitation during the course of a year, typically around 25 centimeters (10 inches), or less. This makes them both difficult places for plants and animals to live. Both deserts have fossil evidence suggesting that this was not always true. Based on fossil evidence, the Sahara and Antarctica appear to have been the homes of many plants and animals in the past.

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show/hide words to know

Bajada: a group of fan-shaped areas on the ground where sand is deposited, starting from a small point (usually in the mountains) and widening until they reach flat ground.

Caliche: a hard rock layer found under some desert floors that is made of calcium, gravel, sand, and other materials in the ground.

Water Signs

Arroyos are also called streambeds, wadis, or washes. Image by Stickpen.

The desert may seem like a barren place, with more open areas of soil surface and much less life than some other biomes. So when we look at the desert, we notice more than just the plants and animals. We also notice some peculiar patterns in the ground.

Although deserts are dry for most of the year, when they do get rain, they can get a lot. This creates all kinds of shapes and paths in the sandy desert floor. The runoff from rain creates deep, broad streambeds, called arroyos or wadis that remain dry for most of the year.

When there is too much rainwater for the streambeds to hold, they start to overflow. Click to enlarge the image.

The Flash Flood

Sometimes, when a lot of rain falls in the desert, the streambeds aren’t deep enough to hold all the water. The water can overflow, rushing across the hard-packed desert floor in a fast moving flash flood. These floods can cover a large section of ground, moving gravel, clay, sand, and other soil particles out of the streams and spreading them out across a broad, flat area. This broad area is called an alluvial fan. Several alluvial fans can cover a larger area, creating a bajada.

Beneath the Dirt

Though water can rush across the sand in deserts, it can also soak in very quickly in some areas. However, sometimes there are unseen barriers to water below the surface. Hard patches of concrete-like material can develop inches or feet below the desert floor. 

Haboobs are huge dust storms with fast moving clouds of dust that can be thousands of feet tall and many miles across. Click to enlarge image.

This material, called caliche or hardpan, is created when minerals like carbon dioxide and water interact and accumulate over time after drying out.

What is a Haboob?

Water isn’t the only driving force that moves dust or creates barriers in the desert. Huge dust storms, called haboobs, can grow to thousands of feet tall, moving soil and minerals miles across the desert. Over enough time, haboobs can even move enough dirt to create sand dunes in some areas.

Additional images via Wikimedia Commons. Sand dunes by user Brocken Inaglory. Racetrack Playa image by Jason Hickey.

Read more about: Delving into Deserts

View citation, bibliographic details:.

• Article: Anatomy of the Desert
• Author(s): Karla Moeller
• Publisher: Arizona State University School of Life Sciences Ask A Biologist
• Site name: ASU - Ask A Biologist
• Date published: July 24, 2013
• Date accessed: May 15, 2024
• Link: https://askabiologist.asu.edu/anatomy-desert

Karla Moeller. (2013, July 24). Anatomy of the Desert. ASU - Ask A Biologist. Retrieved May 15, 2024 from https://askabiologist.asu.edu/anatomy-desert

Chicago Manual of Style

Karla Moeller. "Anatomy of the Desert". ASU - Ask A Biologist. 24 July, 2013. https://askabiologist.asu.edu/anatomy-desert

MLA 2017 Style

Karla Moeller. "Anatomy of the Desert". ASU - Ask A Biologist. 24 Jul 2013. ASU - Ask A Biologist, Web. 15 May 2024. https://askabiologist.asu.edu/anatomy-desert

Delving into Deserts

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