What is a Desert?

A desert is any large, arid area with little to no rainfall, along with little vegetation.

Although incredibly dry, deserts are one of Earth’s main ecosystems and are home to various plants and animals that have adapted to harsh desert conditions.

Despite harsher conditions, deserts can be found on every continent and are home to a large proportion of the Earth’s population.

Low humidity, extreme temperatures, high wind speed, sudden storms, and sandstorms characterize deserts.

Here’s a list of some of Earth’s deserts:

• Namib Desert – Africa
• Sahara Desert – Africa
• Kalahari Desert – Africa
• Great Basin – North America
• Gobi Desert – Asia
• Atacama Desert – South America
• Patagonian Desert – South America
• Antarctic Polar – Antarctica
• Syrian Desert – Asia
• Arabian Desert – Asia
• Arctic Polar – Arctic
• Great Victoria – Australia
• The Chihuahuan Desert – North America

Origin of the Desert

In comparison to other environments around the world, deserts are fairly recent. It is because the world’s deserts result. The Cenozoic Era happened around 65.5 million years ago. During this time, savannas and scrublands developed in the wetter areas near the tropical and temperate margins of the developing deserts.

Moreover, scientists and historians have theorized that several plants commonly found in deserts cropped up during the Miocene Era. The Miocene Era is estimated to have occurred around 23 to 5.3 million years ago. These early desert plants started to grow and develop in the gradually vanishing Tethys Sea region. The Tethys Sea, which is now along the Mediterranean–Central Asian axis, is an extremely salty, arid environment.

It is also believed that deserts may have existed before these periods in the shelter of mountain ranges. These mountain ranges would protect the desert regions from rain. However, these deserts would have existed before the evolution of flowering plants. Only a few plants in modern-day deserts can be traced back to ancient desert vegetation. Today’s foliage in deserts derives from ancestors in much wetter environments.

The Types of Desert

There are different types of deserts, each being created differently.

Subtropical Deserts

Characterized by their extremely high temperatures and low rainfall, subtropical deserts are located just north of the equator between the Tropic of Cancer and Capricorn. The Sahara Desert is the world’s largest hot desert. The Kalahari and the Great Victoria Desert are other examples of subtropical, hot deserts.

How are subtropical deserts formed? These deserts are formed through patterns in airflow. As the sun heats the Earth at the equator, air rises, creating an area of low pressure at the equator.

As the air moves away from the heat source, it cools. The troposphere forces the air to spread high into the atmosphere. Cool air sinks over the tropics, creating high pressure where evaporation and rainfall cannot occur. The cool air spreads out and is drawn back to the equator, where there is a void left by rising air; this creates strong winds (trade winds).

So, there is warm, rising air and heavy rainfall at the equator – here, we get rainforests. But, in the tropics, we have cold, sinking air and get no rain – this creates deserts.

The Sahara Desert

Crossing 11 countries and a large proportion of Northern Africa, the Sahara is the largest subtropical, ‘hot’ desert and the third-largest desert in the world after Antarctica and the Arctic.

The Sahara Desert consists of huge dunes, which cover most of it, mountains, sand plains, and salt flats. The Nile River and the Niger River are both located in the Sahara.

Coastal Deserts

The cold water cools air from the ocean to the shore, producing a fog layer. This fog flows onto the land; although it has high humidity, rainfall is extremely low. It is how a coastal desert is formed.

The Atacama Desert in Chile is an example of a coastal desert and is, in fact, the driest place on Earth.

As mentioned above, certain animals and plants have adapted to living in extreme conditions. Cacti are an example of a plant that has adapted to living in even the driest place on Earth. A cactus stores large amounts of water within them and can survive in areas with little to no rainfall. There are many different species of cacti, and most can be found in North and South America.

Rain Shadow Deserts

When warm, moist air is forced to rise by the shape of the land, this causes relief rainfall. However, on the other side of the hill or slope, cold, dry air will sink back down with little moisture. This air then warms up, making it difficult for clouds to form; this forms deserts.

The Gobi Desert is an example of a rain shadow desert, created through the presence of the Himalayas blocking rainfall from the Indian Ocean from reaching the area.

Polar Deserts

Parts of Antarctica and the Arctic are classed as deserts because water is contained within the glaciers and ice sheets, there’s little to no rainfall, and therefore animals and vegetation cannot live in extreme conditions.

Antarctica is the world’s largest (and coldest) desert.

The Environment in the Desert

While when we think of a desert, we think of a standard dry, sterile environment, there is a lot of variation in environments between different deserts around the world. However, one characteristic is fundamental to the climate of all deserts. This characteristic is a lack of moisture available for plants, which produces an imbalance between precipitation and evapotranspiration.

• Precipitation in Deserts

The average rainfall for deserts ranges greatly, from almost a complete zero in certain South American coastal deserts and Libyan deserts to around 600 millimeters in deserts in Madagascar. The average rainfall for most deserts sits below 400 millimeters. However, this statistic is highly disputed. Some believe the upper limit for annual rainfall in actual deserts is 250 millimeters. These people, therefore, consider the regions with an average rainfall of between 250 and 400 millimeters as semideserts. Regions with this little rainfall are extremely arid, meaning they cannot be farmed and used for agriculture. The only contribution to human food production that deserts can make is providing grazing lands for some livestock.

The reason for the extreme dryness of most desert areas is their location in subtropical regions on either side of the equator belt. The Hadley cell, an atmospheric circulation pattern, is vital to creating the desert climate. It is because, in regions close to the equator, the air near the ground is heated, then rises, expands, and cools. This process causes the condensation of moisture and, as a result, precipitation. However, the rising air moves away from the equatorial region at high levels in the atmosphere, eventually falling into the subtopics. It then moves back towards the equator at much lower altitudes. It is what is known as the Hadley cell atmospheric circulation pattern. The air over the subtropics has already lost most of its moisture. As it descends, it compresses and becomes warmer, causing its humidity even lower.

The lack of rainfall in some deserts worldwide means several years may pass without rain. One of the biggest examples of this is the Cochones desert in Chile. From 1919 to 1964, this desert went a whopping 45 consecutive years without so much as a drop of rain. When rainfall occurs in deserts, it tends to be very heavy in short bursts.

In certain deserts located in coastal areas, fog is a vital source of moisture. Precipitation in these areas is very scarce. Moisture droplets within the fog settle on plants and either drip down onto the soil or are absorbed by plant shoots. In most desert regions, excluding those in coastal areas, there is not enough humidity to allow fog formation.

• The Temperature in Deserts

We often think of all deserts as extreme;y hot; however, there are hot and cold deserts. The temperatures in hot deserts can get extremely high, particularly in summer. The maximum air temperature in hot deserts is more than 40 °C. The highest recorded temperature in any desert was 58 °C in a desert in Libya. The surface of soil’s surface can get even hotter than the air.

Surprisingly, this extreme heat disappears at nighttime because the lack of cloud cover in the desert causes extreme heat during the day. However, this clear sky in the desert also causes a rapid decline in temperature at night. As a result, the minimum temperatures in deserts at nighttime are typically below freezing. However, this is not the case in desert areas close to the sea.

Keep reading for more information on cold deserts!

• Landforms in the Desert

The unique, arid environment of deserts has resulted in the growth of several landforms characteristic of desert areas. Stony plains are one example of these landforms. The surface area of these plains is covered by what is known as ‘desert pavement.’ This pavement is made up of rough gravel and stones. Another landform characteristic of deserts is the rocky plateaus found by arid, steep-sided valleys, known as ‘wadis.’ The most characteristic landform of deserts is the vast areas of loose, mobile sand.

• The Soil in the Desert

Desert soils are largely alkaline and poorly developed. The most common types of soil found in deserts are sandy, gravelly, shallow stony soils, alluvium (materials deposited by bodies of water like rivers or streams), and scree-derived deposits (Rocky materials found at the bottom of cliffs). All of these soils are very dry but do still manage to support some well-developed groups of microorganisms. However, through trampling, domestic animals can have a detrimental effect on the soil in deserts. The impact of this trampling is a reduction in the filtration of water, which, in turn, harms the vegetation and leads to erosion.

What is Desertification?

As a result of drought, deforestation, and threatening agricultural practices, fertile land becomes desert. This process is known as desertification and threatens drylands and fertile land.

As a result of climate change, droughts have become more common. In addition, due to population growth, fertile drylands that experience lower rainfall are increasingly threatened by land degradation. Although drylands account for much of the world’s surface area and are home to over a billion people, desertification is turning these areas into deserts and endangering the life that inhabits these areas.

Desertification can be seen in the Gobi Desert, located in China and Mongolia. The Gobi is growing at an alarming rate due to the effects of desertification on the fertile lands surrounding it.

People have been implementing strategies to combat desertification. These involve planting more trees, improving soil quality, and water management, such as using earth dams to store vast amounts of water in the wet season.

Can a cold desert exist?

Yes, they can! As we’ve touched on above with our mention of polar deserts, cold deserts are very real. It might seem a bit counter-intuitive, but all a desert is, when you boil it down to the basics is a large, arid area of land where little to no rainfall occurs, along with little vegetation. So they can be any temperature, even though we commonly think deserts are hot. Cold deserts are less common because they have more specific requirements for formation, so don’t ditch the camels for your displays just yet!

We can observe two main types of cold deserts in the world around us: Temperate Deserts and Polar Deserts. Here’s a quick breakdown of why these two groups are classed as deserts and why they’re distinct from other types of deserts.

Temperate deserts, also commonly known as ‘cold deserts,’ are, for the most part, much like other deserts: they’re dry, often rocky or sandy, and have very little plant growth. However, as the name would imply, they have a lot more variation in temperature compared to other deserts: a temperate desert usually has very hot summers but freezing winters, whereas a ‘hot’ desert like the Sahara is hot all year round, and even during the summer, a temperate desert will rarely be as hot as a subtropical desert.

It is because temperate deserts usually form in temperate regions further away from the equator—and therefore colder temperatures—than those at which hot deserts are found.

These extremely dry environments are caused by either remoteness from the coast, which results in low atmospheric humidity from a lack of onshore winds, or the presence of high mountains separating the desert from the coast and preventing rainfall from moving further inland. The largest area of temperate desert is the Gobi Desert, which lies in Central Asia, with smaller areas in western North America, southeastern South America, and southern Australia.

While they experience lower temperatures than the more typical hot deserts, temperate deserts are similar in aridity and consequent environmental features, including landforms and soils, so they still look very much like what we’d think of as a desert.

The other main type of cold desert is a bit further from what we’d expect, however. Polar deserts are exactly what the name would indicate: they’re the frozen expanses at the North and South Pole! While it might seem extremely strange to think of the icy poles as being deserts when we go back to our initial description of what a desert is, it’s just a large, arid area of land where little to no rainfall occurs and with little vegetation – and that’s the Poles to a T!

When you think about it, it makes a lot of sense: because the North and South Poles are so far from the sun, the temperatures are so low that there’s very little liquid precipitation: any water that falls from the sky comes down as snow, and because the ground is mostly made up of gravel plains and bedrock, buried beneath layer upon layer of thick ice, it doesn’t melt upon contact with the ground – so although there’s technically water everywhere, in the form of ice and snow, it’s almost all frozen solid, making the Poles almost as arid as the Sahara!

Here are some extra fun facts about Cold Deserts

• If we stick to the less than 250 mm rainfall rule, the polar deserts are the two largest deserts on Earth. It hasn’t been this way for millions of years, however: much of the polar deserts were formed during the recent ice ages, so they are quite young.
• The Antarctic polar deserts and surrounding areas are home to about 90% of all the ice on planet Earth. About 97% of the surface of Antarctica itself consists of ice, although climate change is causing temperatures to rise. Although most of us may not be very aware of their existence, the polar deserts form a vital ecosystem that protects the global balance in climate zones.
• Some inland areas of the Antarctic polar desert can be so incredibly dry that even the Sahara desert experiences more precipitation in one year. However, the most extreme regions in Antarctica only receive about 60 mm of annual rain or snowfall. Since the low temperatures prevent any evaporation, the ice sheets remain; this means today’s ice sheets are a build-up of thousands of years of occasional rain and snow.
• Polar deserts may seem devoid of life, but don’t be fooled by the ‘barren’ icy landscape. You won’t see any trees or animals except some incidental moss and a rare polar fox in the Arctic. But right below the ice caps, you’ll find one of the richest microbial ecosystems on Earth. You’d need microscopic vision to see over half of the creatures in the Arctic and Antarctic!

Dust Storms and Sandstorms

Dust storms and sandstorms are natural phenomena that occur in areas of great aridity with no vegetation to protect the land; this means that they appear very often in deserts. However, dust storms tend to originate not in deserts but in their margins. In a dust storm, the wind begins to blow, and fine particles on the ground vibrate. Then, as the wind picks up, some particles are taken into the air stream. When these particles land, they collide with other particles, then jerk into the air. It begins a chain reaction of particles being whisked up into the air. Depending on several factors, such as the particles’ size, shape, and density, they can move in one of three ways once ejected. First, small particles smaller than 0.1 mm in diameter can be suspended in the air. These tiny particles can be raised as high as 6 km in the air during a dust storm. The presence of these particles in the air greatly reduces visibility, and they can remain there for days. Dense clouds can form during extremely heavy dust storms when strong winds are strong enough. The density of these clouds is so intense that they can completely block out the sun as they travel across the land.

Sandstorms happen much less often than dust storms. Typically, sandstorms occur after intense dust storms when the wind velocity gets up to a point where it can lift heavier particles into the air. These particles, which have a diameter of around 0.5 mm, are lifted into the air briefly before falling back to the ground. It causes other particles to lift into the sky, thus creating a chain reaction. Due to the weight of these particles, they cannot stay in the air for very long, nor are they capable of traveling long distances. Therefore, the particles of sand travel just above the ground at the height of around 30 cm. If the wind is extremely strong, the particles of sand can get as high as 2 m above the ground.

A fascinating fact about sandstorms is that the particles of sand can become electrically charged. As a result, it creates an electric field that can produce sparks and interfere with telecommunications equipment. The electric field is produced by the airborne particles crashing into one another and by the impact of bouncing sand grains on the ground.

12 Amazing Desert Facts

1. Deserts cover one-third of the Earth’s surface.
2. If a place receives less than 25 cm of rain annually, it is considered a desert.
3. The Sahara Desert covers an area of Northern Africa similar to the size of the United States.
4. Polar deserts, like the Arctic and Antarctica, are known as ‘cold deserts’ and ‘frigid deserts.’
5. The Arabian Desert is the second largest ‘hot desert’ after the Sahara.
6. Though incredibly hot in the day, reaching up to 58 degrees Celsius, during the night and in the winter months, the temperature of the Sahara Desert and other ‘hot deserts’ can drop to below freezing.
7. There are parts of the Atacama Desert where no rainfall has ever been recorded.
8. Humans have adapted to living in certain desert areas, creating innovative methods for extracting and collecting water from aquifers and snowmelt from the mountains.
9. Due to desertification, many plants and animals face extinction.
10. The Mojave Desert is located south of the Great Basin Desert and is the driest desert in North America.
11. The Sahara Desert has grown over 10% due to desertification in the last 100 years.
12. Salt flats (or salt pans) are large expanses of the ground made up of salt and other minerals found in deserts. They appear white under the sun’s light. The world’s largest salt flat is the Salar de Uyuni, located in Bolivia.

Do animals and plants live in the deserts of the world?

Despite often harsh and arid conditions, hundreds of desert plants and animals live in deserts.

From cacti, hedgehogs, baboons, and hyenas to owls, ostriches, snakes, and lizards, deserts are home to an array of wildlife. In addition, animals and plants have adapted to living in desert conditions: for example, plants often have deep roots where they can store water.

Desert habitats

Animals and plants will adapt to their environment by migrating or traveling regularly and burrowing underground where it is cooler. Some places you may spot animals and plants in the deserts of the world are:

• Burrows and dens in the sand;
• Animals and plants will travel and meander up the dunes themselves;
• Live near salt basins or salt licks to ensure they’re getting the nutrients they need;
• Rocky cliffs, plateaus, and hills are prime locations for many living organisms;
• Plants are also habitats for smaller animals – and sometimes other plants!
• An oasis is an area of water in a desert. Mostly comprising of natural springs and a few plants, animals like camels will travel long distances between these spots of respite and refuge.

Desert Animals and Plants

Tumbleweeds are a family of desert plants that dry and detach from their stem and roll due to the force of the wind. In some species, this ‘tumbleweed’ isn’t just a part of the plant but the whole plant. When the tumbleweed has reached a wet location, they usually stop and germinate. They release their seeds once they have absorbed water. Tumbleweeds have been known to build up in power lines and fences, which causes problems for people in desert communities.

Dromedary camels are one of the most famous desert animals. In the Sahara, camels are well-adapted to living in their hot, dry environment. A camel’s hump on its back stores fat, a perfect energy reserve and source of hydration that allows them to go more than a week without water or food.

Cacti are a type of desert plant specially adapted to live in deserts. Cacti have extensive root systems, which help them to collect water that can be stored for later use. There are over 1,700 different recorded species of cacti. They range from small, cultivated cacti to the USA and Mexico’s iconic saguaro (pictured below). Some species of cacti have sharp spines to help protect them from animals. These spines can be as sharp and as strong as needles!

Red kangaroos are another famous desert animal. They are found in the Australian outback, the world’s second-largest hot desert (after the Sahara). They survive in this challenging environment by conserving water from fresh vegetation. Kangaroos aren’t usually active in the middle of the day when it’s hottest. Instead, they prefer to relax in the cooler shade. Did you know that kangaroos can jump up to 10 meters in one leap?

Scorpions are another example of a Sahara desert animal. There are over 2000 species of scorpions, with many being poisonous. Scorpions use their pincers to catch insects and the barb on their tail to release deadly venom. The Deathstalker Scorpion is the most lethal type of scorpion. Being able to blend into their environments and being nocturnal allows them to live successfully in the Sahara Desert.

Rattlesnakes live in the deserts of the Southwestern USA and Northern Mexico. Rattlesnakes are the leading cause of snake-related injuries in the USA, although they don’t usually attack unless provoked. They’re also venomous, although if their bites are treated quickly, they’re rarely lethal. Rattlesnakes shake the end of their tail to make a distinctive rattling sound to warn predators; this is how they get their name.

Bactrian camels live in the Gobi Desert. Unlike dromedary camels, these have two humps, which also store fat. During the winter months, the Gobi Desert can be very cold. To survive in this harsh environment, the Bactrian camel has a thick woolly coat to help them stay warm. They can also eat snow to get enough water. Uniquely, Bactrian camels can survive on water that’s saltier than seawater.

Fennec foxes are the world’s smallest canid (that is, it’s the world’s smallest dog-like carnivore). They live in the Sahara Desert and the Sinai Peninsula. The fennec fox has unusually large ears relative to its size. It is a special feature that lets the fox stay cool in warmer temperatures. They can also help the fox to catch its prey at night. The fennec fox also digs burrows to help it stay cool during the daytime.

Addax is the name given to a species of antelope that inhabits the Sahara. Their broad hooves allow them to move on the sand, and their light-colored coat will enable them to blend into their surroundings. The addax can also drink water by extracting it from plants. However, the Addax are now critically endangered due to hunting, and fewer than 100 live in the wild today.