How many continents are there deserts on

Sand dunes in the Sahara Desert of Libya: Most people think of deserts as "sandy" landscapes. That is true part of the time. A desert is a landscape or region that receives very little precipitation - less than mm per year about ten inches. 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 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. The second-largest desert is the Arctic Polar Desert. It has a surface area of about 5. The Canada Glacier is in the background. 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.

A list of more than twenty of the largest non-polar deserts can be found below. 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. Hooves from grazing livestock compact the soil, preventing it from absorbing water and fertilizer s. Agricultural production is devastate d, and the economy of a region suffers.

The deserts of Patagonia , the largest in South America, are expanding due to desertification. Patagonia is a major agricultural region where non-native species such as cattle and sheep graze on grassland. Sheep and cattle have reduced the native vegetation in Patagonia, causing loss of valuable topsoil. More than 30 percent of the grasslands of Argentina, Chile, and Bolivia are faced with desertification. People often overuse natural resources to survive and profit in the short term, while neglecting long-term sustainability.

Madagascar, for instance, is a tropical island in the Indian Ocean. Seeking greater economic opportunities, farmers in Madagascar engaged in slash-and-burn agriculture. This method relies on cutting and burning forests to create fields for crops. Unfortunately, at the time farmers were investing in slash-and-burn agriculture, Madagascar experienced long-term droughts.

With little vegetation to anchor it, the thin topsoil quickly eroded. Rapid population growth also can lead to overuse of resources, killing plant life and depleting nutrients from the soil. Since the s, Lake Chad has shrunk to half its size. Desertification has severely reduced the wetland habitats surrounding the lake, as well as its fishery and grazing lands. Desertification is not new. Millions of people had to leave their farms and seek a living in other parts of the country.

Desertification is an increasing problem. Every year, about 6 million square kilometers 2. The Sahara Desert crept kilometers 39 miles south between and South Africa is losing million metric tons short tons of topsoil each year.

Many countries are working to reduce the rates of desertification. Trees and other vegetation are being planted to break the force of the wind and to hold the soil. Windbreak s made of trees have been planted throughout the Sahel , the southern border region of the Sahara Desert. These windbreaks anchor the soil and prevent sand from invading populated areas. They anchor the drifting sand with a gridlike network of straw fences. Straw is poked partway into the sand, forming a pattern of small squares along the contours of the dunes.

The resulting fences break the force of the wind at ground level, stopping dune movement by confining the sand within the squares of the grid. New technologies are also being developed to combat desertification. Nanoclay keeps the sand moist, clumping it together and preventing it from blowing away.

Deserts Get Hotter Rising temperatures can have huge effects on fragile desert ecosystems. Global warming is the most current instance of climate change. Human activities such as burning fossil fuel s contribute to global warming. In deserts, temperatures are rising even faster than the global average.

This warming has effects beyond simply making hot deserts hotter. For example, increasing temperatures lead to the loss of nitrogen , an important nutrient, from the soil. Heat prevents microbe s from converting nutrients to nitrate s, which are necessary for almost all living things. This can reduce the already limited plant life in deserts.

Climate change also affects rainfall patterns. Climate scientists predict that global warming will lead to more rainfall in some regions, but less rainfall in other places. Areas facing reduced precipitation include areas with some of the largest deserts in the world: North Africa Sahara , the American Southwest Sonoran and Chihuahuan , the southern Andes Patagonia , and western Australia Great Victoria. In literature and in legend, deserts are often described as hostile places to avoid.

Today, people value desert resources and biodiversity. Communities, government s, and organizations are working to preserve desert habitats and increase desert productivity. Hot and Cold Deserts The largest hot desert in the world is the Sahara, which is 9 million square kilometers 3.

It isn't the hottest place on Earth, though. The highest temperature on Earth was recorded there: The largest polar desert is Antarctica, at 13 million square kilometers 5 million square miles. Antarctica boasts the lowest official temperature recorded on Earth: Rising from the Ashes The desert city of Phoenix, Arizona, is named for the mythical desert bird that burns to death only to be reborn, rising from its own ashes.

The city of Phoenix was built on top of the ruins of canals built by the Hohokam people between and CE. The Hohokam used the canals to irrigate their crops. Modern-day residents also rely on an extensive canal system to provide irrigation. Devil of a Storm Dust devils are common in hot deserts. They look like tiny tornadoes, but they start on the ground rather than in the sky.

When patches of ground get very hot, the heated air above them begins to rise and spin. This whirling column of hot air picks up dust and dirt.

These spinning columns of dirt can rise hundreds of feet in the air. Freak Floods Deserts are defined by their dryness. However, flash floods take more lives in deserts than thirst does. Also called industrial agriculture. Also called Ancestral Puebloans. Carbon dioxide is also the byproduct of burning fossil fuels.

Also called the Wet Sahara. Also called hydroelectric energy or hydroelectric power. Monsoon usually refers to the winds of the Indian Ocean and South Asia, which often bring heavy rains. Native American usually does not include Eskimo or Hawaiian people. Also called a salt flat, sink, or salt pan.

Also called a playa, sink, or salt pan. Also called a midlatitude desert. Sometimes, water rights include the amount of water a consumer is allowed to use. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Caryl-Sue, National Geographic Society. Dunn, Margery G. For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource. If a media asset is downloadable, a download button appears in the corner of the media viewer.

If no button appears, you cannot download or save the media. Text on this page is printable and can be used according to our Terms of Service. Any interactives on this page can only be played while you are visiting our website. You cannot download interactives. A terrestrial ecosystem is a land-based community of organisms and the interactions of biotic and abiotic components in a given area.

Examples of terrestrial ecosystems include the tundra, taigas, temperate deciduous forests, tropical rainforests, grasslands, and deserts. The type of terrestrial ecosystem found in a particular place is dependent on the temperature range, the average amount of precipitation received, the soil type, and amount of light it receives.

Use these resources to spark student curiosity in terrestrial ecosystems and discover how different abiotic and biotic factors determine the plants and animals found in a particular place.

A biome is an area classified according to the species that live in that location. Temperature range, soil type, and the amount of light and water are unique to a particular place and form the niches for specific species allowing scientists to define the biome. However, scientists disagree on how many biomes exist. Some count six forest, grassland, freshwater, marine, desert, and tundra , others eight separating two types of forests and adding tropical savannah , and still others are more specific and count as many as 11 biomes.

Use these resources to teach middle school students about biomes around the world. Economies are often molded by the location and cultures of which they are apart. This explains why distinct regional economies develop to serve the unique needs of people. Use these resources to teach students about the regional economies found throughout the world.

Deserts may seem lifeless, but in fact many species have evolved special ways to survive in the harsh environments. Deserts are extremely dry environments that are home to well-adapted plants and animals.

The main types of deserts include hot and dry deserts, semi-arid deserts, coastal deserts, and cold deserts. Join our community of educators and receive the latest information on National Geographic's resources for you and your students.

Skip to content. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. I've been through the desert on a rock with no name.

Photograph by Steve Zappe, MyShot. Also called a wadi. Aswan Dam. Atacama Desert. Cambyses II. Death Valley. Dust Bowl. Fossil fuels formed from the remains of ancient plants and animals. Gobi Desert. Great Plains. Green Sahara. Indus Valley Civilization. Inland Empire. King David. Middle East. Native American. Excess nitrates can choke freshwater ecosystems. Resources can be natural or human. Sahara Desert. Tropic of Cancer. Tropic of Capricorn. Also called an arroyo. It covers an area of approximately 3.

The Namib Desert has the highest dunes in the world. It covers three countries, namely Namibia, South Africa, and Angola. South America has some of the largest deserts in the world including the Patagonian Desert, which is the largest desert in Argentina and the fourth largest in the world.

The Atacama Desert occupies about , square miles across Peru and Chile. Australia has several deserts due to its unique geographical characteristics and climate.

Although Europe has no major deserts, some countries such as Italy, Poland, Serbia, Greece, and Spain have semi-arid areas. In North America, the United States has more than 25 deserts spread across the country, while Mexico has three deserts. In fact, the United States has the highest number of deserts in the world.