Deserts are areas that receive very piffling precipitation. People often employ the adjectives "hot," "dry," and "empty" to describe deserts, simply these words do not tell the whole story. Although some deserts are very hot, with daytime temperatures as high every bit 54°C (130°F), other deserts have common cold winters or are common cold year-circular. And near deserts, far from being empty and lifeless, are home to a variety of plants, animals, and other organisms. People have adapted to life in the desert for thousands of years.

1 thing all deserts have in common is that they are arid, or dry. Most experts agree that a desert is an surface area of land that receives no more than 25 centimeters (10 inches) of precipitation a twelvemonth. The amount of evaporation in a desert often greatly exceeds the annual rainfall. In all deserts, there is little water available for plants and other organisms.

Deserts are found on every continent and embrace about one-fifth of Earth'southward land expanse. They are abode to around 1 billion people—one-6th of the Earth's population.

Although the word "desert" may bring to heed a body of water of shifting sand, dunes cover but most 10 percentage of the world's deserts. Some deserts are mountainous. Others are dry expanses of rock, sand, or salt flats.

Kinds of Deserts

The globe'south deserts can exist divided into five types—subtropical, littoral, rain shadow, interior, and polar. Deserts are divided into these types according to the causes of their dryness.

Subtropical Deserts
Subtropical deserts are caused past the apportionment patterns of air masses. They are found forth the Tropic of Cancer, between 15 and thirty degrees north of the Equator, or along the Tropic of Capricorn, between 15 and thirty degrees southward of the Equator.

Hot, moist air rises into the atmosphere nearly the Equator. As the air rises, it cools and drops its wet as heavy tropical rains. The resulting cooler, drier air mass moves away from the Equator. Equally it approaches the tropics, the air descends and warms up again. The descending air hinders the formation of clouds, and so very lilliputian pelting falls on the state below.

The world's largest hot desert, the Sahara, is a subtropical desert in northern Africa. The Sahara Desert is nigh the size of the entire continental United States. Other subtropical deserts include the Kalahari Desert in southern Africa and the Tanami Desert in northern Australia.

Coastal Deserts
Cold ocean currents contribute to the formation of coastal deserts. Air bravado toward shore, chilled by contact with cold water, produces a layer of fog. This heavy fog drifts onto land. Although humidity is high, the atmospheric changes that normally cause rainfall are non present. A coastal desert may exist almost totally rainless, yet clammy with fog.

The Atacama Desert, on the Pacific shores of Chile, is a coastal desert. Some areas of the Atacama are oftentimes covered by fog. Just the region tin go decades without rainfall. In fact, the Atacama Desert is the driest identify on Earth. Some weather stations in the Atacama have never recorded a driblet of rain.

Rain Shadow Deserts
Rain shadow deserts exist well-nigh the leeward slopes of some mountain ranges. Leeward slopes face up away from prevailing winds.

When moisture-laden air hits a mount range, it is forced to ascension. The air and so cools and forms clouds that drib moisture on the windward (wind-facing) slopes. When the air moves over the mountaintop and begins to descend the leeward slopes, there is trivial moisture left. The descending air warms upwardly, making it difficult for clouds to form.

Expiry Valley, in the U.S. states of California and Nevada, is a rain shadow desert. Death Valley, the everyman and driest place in Due north America, is in the rain shadow of the Sierra Nevada mountains.

Interior Deserts
Interior deserts, which are establish in the heart of continents, exist because no wet-laden winds accomplish them. By the time air masses from coastal areas accomplish the interior, they have lost all their moisture. Interior deserts are sometimes called inland deserts.

The Gobi Desert, in Communist china and Mongolia, lies hundreds of kilometers from the ocean. Winds that reach the Gobi have long since lost their moisture. The Gobi is as well in the rain shadow of the Himalaya mountains to the south.

Polar Deserts
Parts of the Arctic and the Antarctic are classified every bit deserts. These polar deserts contain bully quantities of water, but virtually of it is locked in glaciers and water ice sheets twelvemonth-round. So, despite the presence of millions of liters of water, in that location is actually petty available for plants and animals.

The largest desert in the world is also the coldest. About the entire continent of Antarctica is a polar desert, experiencing little precipitation. Few organisms can withstand the freezing, dry climate of Antarctica.

Changing Deserts

The regions that are deserts today were not always so dry. Betwixt 8000 and 3000 BCE, for case, the Sahara had a much milder, moister climate. Climatologists identify this period equally the "Green Sahara."

Archaeological bear witness of past settlements is abundant in the middle of what are arid, unproductive areas of the Sahara today. This evidence includes rock paintings, graves, and tools. Fossils and artifacts show that lime and olive trees, oaks, and oleanders once bloomed in the Sahara. Elephants, gazelles, rhinos, giraffes, and people used stream-fed pools and lakes.

There were three or four other moist periods in the Sahara. Like lush conditions existed as recently equally 25,000 years ago. Between the moist periods came periods of dryness much like today's.

The Sahara is not the just desert to have dramatic climate change. The Ghaggar River, in what is now India and Pakistan, was a major water source for Mohenjo-daro, an urban surface area of the ancient Indus Valley Civilization. Over time, the Ghaggar changed course and at present only flows during the rainy monsoon flavour. Mohenjo-daro is now a function of the vast Thar and Cholistan deserts.

Most of Earth'due south deserts will continue to undergo periods of climate change.

Desert Characteristics

Humidity—water vapor in the air—is near zero in nigh deserts. Lite rains oft evaporate in the dry air, never reaching the ground. Rainstorms sometimes come up as violent cloudbursts. A cloudburst may bring equally much as 25 centimeters (10 inches) of rain in a single 60 minutes—the only rain the desert gets all year.

Desert humidity is usually so depression that not plenty water vapor exists to form clouds. The sun'due south rays beat out downwards through clement skies and broil the land. The ground heats the air so much that air rises in waves you tin can really meet. These shimmering waves misfile the center, causing travelers to see distorted images called mirages.

Temperature extremes are a characteristic of almost deserts. In some deserts, temperatures rise then high that people are at risk of dehydration and even decease. At night, these areas absurd quickly because they lack the insulation provided past humidity and clouds. Temperatures tin drop to iv°C (40°F) or lower.

In the Chihuahuan Desert, in the United States and Mexico, temperatures tin vary by dozens of degrees in one twenty-four hours. Daytime temperatures in the Chihuahua can climb beyond 37°C (100°F), while nighttime temperatures can dip below freezing (0°C or 32°F).

Winds at speeds of about 100 kilometers per hr (60 miles per hour) sweep through some deserts. With little vegetation to cake it, the air current tin conduct sand and dust across entire continents and even oceans. Windstorms in the Sahara bung so much textile into the air that African dust sometimes crosses the Atlantic Ocean. Sunsets on the Atlantic declension of the U.S. country of Florida, for example, tin be tinted xanthous.

First-time visitors to deserts are ofttimes amazed by the unusual landscapes, which may include dunes, towering blank peaks, flat-topped rock formations, and smoothly polished canyons. These features differ from those of wetter regions, which are frequently gently rounded by regular rainfall and softened by lush vegetation.

Water helps carve desert lands. During a sudden storm, water scours the dry, difficult-baked state, gathering sand, rocks, and other loose material as it flows. As the dirty water roars downhill, it cuts deep channels, called arroyos or wadis. A thunderstorm tin send a fast-moving torrent of water—a wink overflowing—down a dry arroyo. A flash flood like this tin sweep away annihilation and anyone in its path. Many desert regions discourage visitors from hiking or camping in arroyos for this reason.

Even urban areas in deserts can exist vulnerable to flash floods. The city of Jeddah, Kingdom of saudi arabia, sits in the Arabian Desert. In 2011, Jeddah was struck by a sudden thunderstorm and wink alluvion. Roads and buildings were washed abroad, and more than 100 people died.

Fifty-fifty in a desert, water and current of air eventually vesture away softer rock. Sometimes, rock is carved into tablelike formations such as mesas and buttes. At the foot of these formations, water drops its brunt of gravel, sand, and other sediment, forming deposits called alluvial fans.

Many deserts accept no drainage to a river, lake, or ocean. Rainwater, including water from flash floods, collects in big depressions chosen basins. The shallow lakes that course in basins somewhen evaporate, leaving playas, or salt-surfaced lake beds. Playas, too chosen sinks, pans, or salt flats, can exist hundreds of kilometers wide.

The Black Rock Desert in the U.Southward. state of Nevada, for example, is all that remains of the prehistoric Lake Lahontan. The hard, apartment surface of desert salt flats are oft ideal for car racing. In 1997, British pilot Andy Greenish ready the land speed tape in Black Stone Desert—i,228 kilometers per hour (763 miles per hour). Greenish'southward vehicle, the ThrustSSC, was the first car to suspension the sound barrier.

Current of air is the primary sculptor of a desert's hills of sand, called dunes. Wind builds dunes that rising as loftier as 180 meters (590 feet). Dunes migrate constantly with the air current. They commonly shift a few meters a year, merely a particularly violent sandstorm can motility a dune 20 meters (65 feet) in a single 24-hour interval.

Sandstorms may coffin everything in their path—rocks, fields, and fifty-fifty towns. I legend holds that the Persian Emperor Cambyses II sent an regular army of 50,000 men to the Siwa Oasis in western Egypt around 530 BCE. Halfway in that location, an enormous sandstorm swallowed the entire group. Archaeologists in the Sahara accept been unsuccessfully looking for the "Lost Army of Cambyses" ever since.

Water in the Desert

Pelting is usually the main source of water in a desert, but it falls very rarely. Many desert dwellers rely on groundwater, stored in aquifers below the surface. Groundwater comes from pelting or other precipitation, like snow or hail. Information technology seeps into the ground, where it tin can remain for thousands of years.

Underground water sometimes rises to the surface, forming springs or seeps. A fertile green area chosen an oasis, or cienega, may be nigh such a water source. Near 90 major, inhabited oases dot the Sahara. These oases are supported past some of the world's largest supplies of underground water. People, animals, and plants all surround these oases, which provide stable access to water, food, and shelter.

When groundwater doesn't seep to the surface, people often drill into the ground to get to it. Many desert cities, from the American Southwest to the Middle Due east, rely heavily on such aquifers to fill their water needs. Rural Israeli communities chosen kibbutzim rely on aquifers to furnish water for crops and even fish farming in the dry out Negev Desert.

Drilling into aquifers provides water for drinking, agriculture, industry, and hygiene. However, it comes at a cost to the environment. Aquifers accept a long time to refill. If desert communities employ groundwater faster than information technology is replenished, water shortages can occur. The Mojave Desert, in southern California and Nevada, for instance, is sinking due to aquifer depletion. The booming desert communities of Las Vegas, Nevada, and California's "Inland Empire" are using h2o faster than the aquifer is being refilled. The h2o level in the aquifer has sunk as much every bit 30 meters (100 feet) since the 1950s, while the land in a higher place the aquifer has sunk every bit much as 10 centimeters (4 inches).

Rivers sometimes provide water in a desert. The Colorado River, for instance, flows through iii deserts in the American Southwest: the Swell Basin, the Sonoran, and the Mojave. Seven states—Wyoming, Colorado, Utah, New Mexico, Nevada, Arizona, and California—rely on the river for some of their water supply.

People often modify rivers to aid distribute and store h2o in a desert. The Nile River ecosystem dominates the eastern part of the Sahara Desert, for instance. The Nile provides the well-nigh reliable, plentiful source of freshwater in the region. Between 1958 and 1971, the regime of Arab republic of egypt constructed a massive dam on the Upper Nile (the southern function of the river, about Egypt's edge with Sudan). The Aswan Dam harnesses the ability of the Nile for hydroelectricity used in industry. Information technology likewise stores water in a manmade lake, Lake Nasser, to protect the country'due south communities and agriculture confronting drought.

Construction of the Aswan High Dam was a huge engineering projection. Local desert communities can divert rivers on a smaller scale. Throughout the Middle E, communities accept dug bogus wadis, where freshwater can flow during rainy seasons. In countries like Yemen, artificial wadis can carry enough water for whitewater rafting trips during sure times of the year.

When deserts and water supplies cantankerous state and national borders, people oft fight over water rights. This has happened amid the states in the Colorado River Basin, which have negotiated for many years over the division of the river's water. Rapidly expanding populations in California, Nevada, and Arizona have compounded the problem. Agreements that were made in the early on 20th century failed to account for Native American water rights. Mexican access to the Colorado, which has its delta in the Mexican state of Baja California, was ignored. Desert agriculture, including cotton production, demanded a large portion of the Colorado. The environmental bear upon of dams was not considered when the structures were built. States of the Colorado River Basin go on to negotiate today to prepare for population growth, agronomical development, and the possibility of time to come droughts.

Life in the Desert

Plants and animals adapt to desert habitats in many ways. Desert plants grow far apart, allowing them to obtain equally much water effectually them as possible. This spacing gives some desert regions a desolate advent.

In some deserts, plants have unique leaves to capture sunlight for photosynthesis, the process plants apply to brand food. Small pores in the leaves, called stomata, take in carbon dioxide. When they open up, they also release water vapor. In the desert, all these stomata would quickly dry out out a plant. And so desert plants typically have tiny, waxy leaves. Cactuses have no leaves at all. They produce food in their greenish stems.

Some desert plants, such as cactuses, accept shallow, wide-spreading root systems. The plants soak up water speedily and store information technology in their cells. Saguaro cactuses, which live in the Sonoran Desert of Arizona and northern Mexico, expand similar accordions to shop water in the cells of their trunks and branches. A large saguaro is a living storage tower that tin hold hundreds of liters of water.

Other desert plants have very deep roots. The roots of a mesquite tree, for instance, can achieve water more than 30 meters (100 feet) hush-hush.

Mesquites, saguaros, and many other desert plants also have thorns to protect them from grazing animals.

Many desert plants are annuals, which means they simply live for ane season. Their seeds may lie dormant for years during long dry spells. When rain finally comes, the seeds sprout quickly. Plants grow, bloom, produce new seeds, and die, oft in a brusk span of time. A soaking rain can change a desert into a wonderland of flowers almost overnight.

Animals that have adapted to a desert environment are chosen xerocoles. Xerocoles include species of insects, reptiles, birds, and mammals. Some xerocoles avoid the sun by resting in scarce shade. Many escape the oestrus in cool burrows they dig in the ground. The fennec fox, for example, is native to the Sahara Desert. Fennec flim-flam communities piece of work together to dig large burrows, some as large as 93 foursquare meters (1,000 square anxiety). Dew can collect in these burrows, providing the foxes with fresh water. However, fennec foxes have adjusted and then they do not have to drink water at all: Their kidneys retain enough water from the food they eat.

Virtually xerocoles are nocturnal. They sleep through the hot days and do their hunting and foraging at nighttime. Deserts that seem desolate during the mean solar day are very active in the absurd dark air. Foxes, coyotes, rats, and rabbits are all nocturnal desert mammals. Snakes and lizards are familiar desert reptiles. Insects such as moths and flies are abundant in the desert. Almost desert birds are restricted to areas near water, such equally river banks. Nevertheless, some birds, such as the roadrunner, have adapted to life in the desert. The roadrunner, native to the deserts of North America, obtains water from its food.

Some xerocoles have bodies that help them handle the heat. A desert tortoise's thick shell insulates the animal and reduces water loss. Sand lizards, native to the deserts of Europe and Asia, are nicknamed "dancing lizards" because of the way they chop-chop lift one leg at a time off the hot desert sand. A jackrabbit'southward long ears contain blood vessels that release estrus. Some desert vultures urinate on their own legs, cooling them by evaporation.

Many desert animals have developed ingenious ways of getting the water they need. The thorny devil, a lizard that lives in the Australian Outback, has a arrangement of tiny grooves and channels on its body that lead to its oral fissure. The lizard catches rain and dew in these grooves and sucks them into its oral cavity by gulping.

Camels are very efficient water users. The animals practise not store water in their humps, as people one time believed. The humps shop fat. Hydrogen molecules in the fat combine with inhaled oxygen to form water. During a shortage of food or water, camels draw upon this fat for nutrition and moisture. Dromedary camels, native to the Arabian and Sahara deserts, can lose upwardly to 30 percentage of their body weight without impairment. Camels, nicknamed "ships of the desert," are widely used for transportation, meat, and milk in the Maghreb (a region in Northwest Africa), the Center East, and the Indian Subcontinent.

People and the Desert

Most 1 billion people live in deserts. Many of these people rely on centuries-old customs to make their lives as comfy as possible

Civilizations throughout the Middle East and Maghreb have adapted their habiliment to the hot, dry conditions of the Sahara and Arabian deserts. Vesture is versatile and based on robes fabricated of rectangles of fabric. Long-sleeved, full-length, and frequently white, these robes shield all but the head and hands from the air current, sand, oestrus, and cold. White reflects sunlight, and the loose fit allows cooling air to menstruation across the skin.

These robes of loose fabric can exist adjusted (folded) for length, sleeves, and pockets, depending on the wearer and the climate. A thobe is a full-length, long-sleeved white robe. An abaya is a sleeveless cloak that protects the wearer from grit and heat. A djebba is a brusk, square pullover shirt worn by men. A kaffiyeh is a rectangular piece of cloth folded loosely around the head to protect the wearer from lord's day exposure, grit, and sand. It tin can be folded and unfolded to cover the mouth, nose, and eyes. Kaffiyehs are secured effectually the caput with a cord called an agal. A turban is similar to a kaffiyeh, simply wrapped around the head instead of being secured with an agal. Turbans are also much longer—upwards to six meters (20 anxiety)!

Desert dwellers have also adjusted their shelters for the unique climate. The ancient Anasazi peoples of the southwestern United States and northern Mexico constructed huge apartment complexes in the rocky cliffs of the Sonoran Desert. These cliff dwellings, sometimes dozens of meters off the ground, were constructed with thick, earthen walls that provided insulation. Although temperatures outside varied profoundly from day to dark, temperatures within did not. Tiny, high windows permit in just a fiddling light and helped keep out grit and sand.

The demand to notice nutrient and water has led many desert civilizations to become nomadic. Nomadic cultures are those that do non have permanent settlements. In the deserts of the Heart East and Asia, nomadic tent communities continue to flourish. Tent walls are fabricated of thick, sturdy material that can go on out sand and dust, but as well allow cool breezes to blow through. Tents tin be rolled upwardly and transported on pack animals (usually horses, donkeys, or camels). Nomads motility frequently so their flocks of sheep and goats will have water and grazing land.

Too animals like camels and goats, a multifariousness of desert vegetation is constitute in oases and along the shores of rivers and lakes. Figs, olives, and oranges thrive in desert oases and have been harvested for centuries.

Some desert areas rely on resources brought from more fertile areas—food trucked in from distant farmlands or, more often, water piped from wetter regions. Big areas of desert soil are irrigated past h2o pumped from underground sources or brought by canal from distant rivers or lakes. The booming Inland Empire of southeastern California is made upward of deserts (the Mojave and the Sonoran) that rely on water for agriculture, manufacture, and residential evolution. Canals and aqueducts supply the Inland Empire with water from the Colorado River, to the east, and the Sierra Nevada snowmelt to the northward.

A variety of crops can thrive in these irrigated oases. Sugar cane is a very h2o-intensive crop by and large harvested in tropical regions. Nonetheless, sugar pikestaff is also harvested in the deserts of Pakistan and Commonwealth of australia. Water for irrigation is transported from hundreds of kilometers away, or drilled from hundreds of meters hole-and-corner.

Oases in desert climates have been pop spots for tourists for centuries. Spas ring the Dead Ocean, a saline lake in the Judean Desert of Israel and Hashemite kingdom of jordan. The Dead Sea has had flourishing spas since the time of King David.

Air transportation and the development of air conditioning have fabricated the sunny climate of deserts even more accessible and attractive to people from colder regions. Populations at resorts like Palm Springs, California, and Las Vegas, Nevada, have boomed. Desert parks, such as Death Valley National Park, California, concenter thousands of visitors every year. People who drift to the warm, dry desert for the winter and return to more temperate climates in the spring are sometimes called "snowbirds."

In rural areas, hot days turn into cool nights, providing welcome relief from the scorching sun. Only in cities, structures like buildings, roads, and parking lots concord on to daytime heat long later the lord's day sets. The temperature stays high even at night, making the city an "island" of heat in the middle of the desert. This is called the urban heat island effect. It is less pronounced in desert cities than cities built in heavily forested areas.  Cities similar New York Metropolis, New York, and Atlanta, Georgia, can be 5 degrees warmer than the surrounding area. New York was congenital on wetland habitat, and Atlanta was built in a wooded surface area. Cities like Phoenix, Arizona, or Kuwait City, Kuwait, have a much smaller urban rut island effect. They may be only slightly warmer than the surrounding desert.

Deserts can hold economically valuable resources that drive civilizations and economies. The most notable desert resource in the world is the massive oil reserves in the Arabian Desert of the Middle East. More than than one-half of the proven oil reserves in the world lie beneath the sands of the Arabian Desert, mostly in Saudi arabia. The oil industry draws companies, migrant workers, engineers, geologists, and biologists to the Eye East.

Desertification

Desertification is the process of productive cropland turning into not-productive, desert-like environments. Desertification commonly happens in semi-arid areas that edge deserts.

Human activities are a primary cause of desertification. These activities include overgrazing of livestock, deforestation, overcultivation of farmland, and poor irrigation practices. Overgrazing and deforestation remove plants that ballast the soil. As a result, wind and water erode the food-rich topsoil. Hooves from grazing livestock compact the soil, preventing information technology from absorbing water and fertilizers. Agronomical production is devastated, and the economic system 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 not-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 Republic of 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 case, is a tropical island in the Indian Body of water. Seeking greater economic opportunities, farmers in Republic of madagascar engaged in slash-and-burn agriculture. This method relies on cut and burning forests to create fields for crops. Unfortunately, at the fourth dimension farmers were investing in slash-and-burn agriculture, Madagascar experienced long-term droughts. With little vegetation to anchor it, the thin topsoil quickly eroded. The island's central plateau is now a barren desert.

Rapid population growth besides can lead to overuse of resources, killing plant life and depleting nutrients from the soil. Lake Chad is a source of freshwater for four countries on the edge of the Sahara Desert: Chad, Cameroon, Niger, and Nigeria. These developing countries use Lake Chad's shallow waters for agriculture, manufacture, and hygiene. Since the 1960s, Lake Chad has shrunk to half its size. Desertification has severely reduced the wetland habitats surrounding the lake, every bit well every bit its fishery and grazing lands.

Desertification is not new. In the 1930s, parts of the Great Plains of Due north America became the "Grit Bowl" through a combination of drought and poor farming practices. Millions of people had to leave their farms and seek a living in other parts of the land.

Desertification is an increasing problem. Every year, about vi million square kilometers (two.three million square miles) of land get useless for cultivation due to desertification. The Sahara Desert crept 100 kilometers (39 miles) southward between 1950 and 1975. South Africa is losing 300-400 meg metric tons (330-441 brusque tons) of topsoil each twelvemonth.

Many countries are working to reduce the rates of desertification. Trees and other vegetation are being planted to intermission the strength of the current of air and to concur the soil. Windbreaks fabricated of copse have been planted throughout the Sahel, the southern edge region of the Sahara Desert. These windbreaks ballast the soil and prevent sand from invading populated areas.

In People's republic of china's Tengger Desert, researchers have developed another style to control wandering dunes. They anchor the drifting sand with a gridlike network of straw fences. Harbinger is poked partway into the sand, forming a pattern of small-scale squares forth the contours of the dunes. The resulting fences intermission the force of the wind at ground level, stopping dune movement past circumscribed the sand within the squares of the grid.

New technologies are as well being developed to gainsay desertification. "Nanoclay" is a substance sprayed on desert sands that acts as a binding amanuensis. Nanoclay keeps the sand moist, clumping it together and preventing information technology from blowing abroad.

Deserts Get Hotter

Rising temperatures can have huge effects on delicate desert ecosystems. Global warming is the most current instance of climate change. Human activities such as burning fossil fuels contribute to global warming.

In deserts, temperatures are rising even faster than the global boilerplate. This warming has furnishings beyond simply making hot deserts hotter. For example, increasing temperatures pb to the loss of nitrogen, an important nutrient, from the soil. Estrus prevents microbes from converting nutrients to nitrates, 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 atomic number 82 to more rainfall in some regions, merely less rainfall in other places. Areas facing reduced precipitation include areas with some of the largest deserts in the globe: Northward Africa (Sahara), the American Southwest (Sonoran and Chihuahuan), the southern Andes (Patagonia), and western Commonwealth of australia (Peachy Victoria).

In literature and in fable, deserts are ofttimes described as hostile places to avoid. Today, people value desert resources and biodiversity. Communities, governments, and organizations are working to preserve desert habitats and increase desert productivity.

desert

I've been through the desert on a rock with no name.

Hot and Common cold Deserts
The largest hot desert in the world is the Sahara, which is 9 meg square kilometers (three.v million foursquare miles). Information technology isn't the hottest identify on Earth, though. That stardom belongs to Death Valley, in California's Mojave Desert. The highest temperature on Earth was recorded in that location: 56.7 C (134.1 F).

The largest polar desert is Antarctica, at xiii million square kilometers (5 million square miles). Antarctica boasts the lowest official temperature recorded on World: -89.2 C (-128.half-dozen F), recorded on July 21, 1983.

Rising from the Ashes
The desert city of Phoenix, Arizona, is named for the mythical desert bird that burns to decease only to exist 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 500 and 1450 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 Tempest
Grit devils are common in hot deserts. They await like tiny tornadoes, only 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 upwards dust and dirt. These spinning columns of dirt tin can rise hundreds of feet in the air.

Freak Floods
Deserts are defined by their dryness. However, flash floods have more lives in deserts than thirst does.

abaya

Substantive

long, thin, loose cloak worn past some Muslim women.

accessibility

Noun

the ease with which a place or thing tin exist reached from other places.

adapt

Verb

to adjust to new surroundings or a new situation.

agal

Noun

cord wrapped around a kaffiyeh, or head roofing, to keep it in place.

agricultural development

Noun

modern farming methods that include mechanical, chemic, engineering science and technological methods. Besides called industrial agronomics.

Noun

the art and science of cultivating land for growing crops (farming) or raising livestock (ranching).

air conditioning

Substantive

organisation that cools the air.

Noun

a large volume of air that is mostly consequent, horizontally, in temperature and humidity.

Noun

fan-shaped deposit of eroded material, commonly sediment and sand.

alluvium

Noun

gravel, sand, and smaller materials deposited by flowing water.

Anasazi

Noun

(1200 BCE-1300 CE) people and civilization native to what is now the southwestern Us. Likewise called Ancestral Puebloans.

anchor

Verb

to concur firmly in place.

aboriginal

Adjective

very sometime.

Antarctic

Noun

region at World's extreme southward, encompassed by the Antarctic Circle.

aqueduct

Noun

a pipe or passage used for carrying water from a altitude.

Noun

an undercover layer of rock or earth which holds groundwater.

aquifer depletion

Substantive

process past which people pump more h2o out of aquifers than tin be replaced by rain or snow.

archaeological

Adjective

having to do with the study of ancient people and cultures.

archaeologist

Noun

person who studies artifacts and lifestyles of aboriginal cultures.

Noun

region at World'due south extreme north, encompassed by the Chill Circle.

arroyo

Noun

deep channel or canyon, often dry except during flash floods. Also chosen a wadi.

Noun

material remains of a culture, such equally tools, wear, or food.

Aswan Dam

Noun

organisation of 2 dams in Egypt that command the catamenia of the Nile River for agricultural, electrical, and sanitary uses.

Atacama Desert

Noun

large, nearly rainless desert in western South America.

atmospheric changes

Substantive

alterations in the layer of air surrounding the Globe, such as an increment of pollution or humidity.

Substantive

a dip or depression in the surface of the country or ocean floor.

Noun

all the different kinds of living organisms within a given expanse.

biologist

Substantive

scientist who studies living organisms.

couch

Noun

small-scale hole or tunnel used for shelter.

Noun

unmarried hill or stone formation that rises sharply from a flat landscape, usually in a desert.

cactus

Noun

type of plant native to dry regions.

Cambyses Two

Noun

(?-522 BCE) emperor of Persia.

canal

Noun

artificial waterway.

Noun

deep, narrow valley with steep sides.

carbon dioxide

Noun

greenhouse gas produced by animals during respiration and used by plants during photosynthesis. Carbon dioxide is also the byproduct of burning fossil fuels.

cattle

Noun

cows and oxen.

jail cell

Noun

smallest working part of a living organism.

characteristic

Noun

physical, cultural, or psychological characteristic of an organism, place, or object.

cienega

Substantive

haven or swampy wetland, usually fed by natural springs.

circulation

Noun

moving in a round movement.

Noun

complex manner of life that adult every bit humans began to develop urban settlements.

Noun

steep wall of rock, earth, or water ice.

climate

Substantive

all atmospheric condition atmospheric condition for a given location over a period of time.

Noun

gradual changes in all the interconnected weather elements on our planet.

climatologist

Noun

person who studies long-term patterns in weather.

Noun

visible mass of tiny water aerosol or ice crystals in Earth'due south atmosphere.

cloudburst

Noun

sudden, heavy rainfall.

coastal desert

Substantive

arid areas usually found on the western edges of continents almost the Tropic of Cancer and the Tropic of Capricorn.

Substantive

ane of the vii chief land masses on World.

cotton

Noun

material made from fibers of the cotton found.

Noun

agronomical produce.

cultivate

Verb

to prepare and nurture the land for crops.

Noun

steady, predictable flow of fluid inside a larger body of that fluid.

dam

Noun

structure congenital across a river or other waterway to control the flow of water.

Death Valley

Noun

(~3,900 square kilometers/ane,500 square miles) dry basin in the U.South. states of California and Nevada, the lowest point in Northward America (86 meters/282 feet below sea level).

Noun

devastation or removal of forests and their undergrowth.

dehydration

Noun

illness in which the body loses too much water.

Noun

area of state that receives no more than 25 centimeters (ten inches) of precipitation a year.

desertification

Noun

rapid depletion of plant life and topsoil, often associated with drought and human activeness.

desolate

Adjective

barren, spare, or lonely.

devastate

Verb

to destroy.

Noun

h2o droplets condensed from the temper onto cool surfaces near the ground.

divert

Verb

to direct away from a familiar path.

djebba

Noun

brusque, pullover tunic or shirt worn past men.

dominate

Verb

to overpower or control.

fallow

Describing word

state of minimal growth or action.

Noun

period of greatly reduced precipitation.

Noun

a mound or ridge of loose sand that has been deposited by air current.

Noun

tiny, dry particles of material solid enough for wind to carry.

Grit Bowl

Noun

(1930-1940) term for the Great Plains of the U.S. and Canada when severe dust storms forced thousands of people off their farms.

economic system

Noun

system of production, distribution, and consumption of goods and services.

Noun

customs and interactions of living and nonliving things in an area.

efficient

Adjective

performing a task with skill and minimal waste.

engineering

Noun

the art and science of edifice, maintaining, moving, and demolishing structures.

enormous

Adjective

very large.

Noun

imaginary line around the Earth, some other planet, or star running due east-west, 0 degrees latitude.

Noun

process by which liquid water becomes water vapor.

exceed

Verb

to go beyond the limit.

fertile

Describing word

able to produce crops or sustain agronomics.

fertilizer

Noun

food-rich chemic substance (natural or manmade) applied to soil to encourage constitute growth.

fishery

Noun

industry or occupation of harvesting fish, either in the wild or through aquaculture.

fish farming

Substantive

art and scientific discipline of raising and harvesting fish and other seafood, such as shrimp or crabs.

flash alluvion

Noun

sudden, short, and heavy catamenia of water.

flourish

Verb

to thrive or exist successful.

Noun

clouds at ground level.

forage

Verb

to search for food or other needs.

forest

Verb

to cover with trees and other vegetation.

Substantive

remnant, impression, or trace of an ancient organism.

fossil fuel

Noun

coal, oil, or natural gas. Fossil fuels formed from the remains of ancient plants and animals.

fragile

Noun

delicate or easily broken.

geologist

Noun

person who studies the physical formations of the Earth.

Substantive

mass of water ice that moves slowly over land.

Noun

increase in the average temperature of the Earth's air and oceans.

Gobi Desert

Noun

large desert in China and Mongolia.

government

Noun

organisation or club of a nation, state, or other political unit.

grassland

Substantive

ecosystem with large, apartment areas of grasses.

grave

Substantive

specific place where a trunk is buried.

gravel

Noun

small stones or pebbles.

grazing animal

Noun

beast that feeds on grasses, trees, and shrubs.

Great Plains

Noun

grassland region of North America, between the Rocky Mountains and the Mississippi River.

Dark-green Sahara

Noun

(7000-3000 BCE) moist, temperate climate of the nowadays-twenty-four hours Sahara Desert during the Neolithic Subpluvial period. Likewise chosen the Wet Sahara.

Noun

water found in an aquifer.

Substantive

environment where an organism lives throughout the year or for shorter periods of time.

hinder

Verb

to delay or hold dorsum.

hoof

Noun

thick, horny covering of the anxiety of animals such as horses and cattle.

hostile

Adjective

confrontational or unfriendly.

Noun

amount of water vapor in the air.

hydroelectricity

Substantive

power generated by moving h2o converted to electricity. Also called hydroelectric free energy or hydroelectric power.

hydrogen

Noun

chemical element with the symbol H, whose most mutual isotope consists of a unmarried electron and a single proton.

hygiene

Substantive

science and methods of keeping clean and healthy.

Noun

thick layer of glacial water ice that covers a large expanse of land.

manufacture

Noun

activity that produces appurtenances and services.

Indus Valley Civilization

Noun

(2500-1500 B.C.E.) civilization that flourished in the Indus River Valley, in present-day Islamic republic of pakistan.

ingenious

Adjective

very clever or smart.

Inland Empire

Noun

desert region in southern California, consisting of parts of Riverside, San Bernardino, and Los Angeles counties.

insulation

Noun

material used to proceed an object warm.

interior desert

Noun

barren surface area found in the interior of continents, formed because no moisture-laden winds attain them.

kaffiyeh

Noun

short headdress worn past Arab men and tied with a cord (agal).

kibbutzim

Plural Substantive

(singular: kibbutz) Israeli agricultural community organized under collective principles.

kidney

Substantive

organ that removes the waste product products from blood and helps regulate general wellness.

King David

Noun

(?1050-970 BCE) king of ancient Israel and major religious figure for Judaism, Christianity, and Islam.

Noun

the geographic features of a region.

leeward

Adjective

downwind, or facing away from prevailing winds.

legendary

Describing word

famous, heroic, or celebrated.

literature

Noun

written material, including novels, poesy, drama and history.

livestock

Noun

animals raised for human use.

lush

Adjective

abundant and rich.

Maghreb

Noun

region in Northward Africa made of v countries: Morocco, Algeria, Tunisia, Libya, and Islamic republic of mauritania.

Noun

wide, flat-topped landform with steep sides.

mesquite

Noun

tree or shrub native to the hot deserts of North America.

microbe

Noun

tiny organism, unremarkably a bacterium.

Middle East

Noun

region of southwest asia and northeast Africa.

migrate

Verb

to motility from one place or activity to another.

delusion

Substantive

optical illusion formed nether certain atmospheric conditions, in which objects appear to exist reflected or displaced.

alter

Verb

to change or alter.

Mohenjo-daro

Noun

(2600-1500 BCE) metropolis of the Indus Valley civilization, in what is today Pakistan.

molecule

Noun

smallest physical unit of a substance, consisting of two or more atoms linked together.

Noun

seasonal change in the direction of the prevailing winds of a region. Monsoon usually refers to the winds of the Indian Ocean and S Asia, which often bring heavy rains.

mountain range

Noun

series or chain of mountains that are close together.

nanoclay

Substantive

collection of tiny particles that acts equally a binding agent to materials such as sand or plastics.

Native American

Noun

person whose ancestors were native inhabitants of North or South America. Native American usually does not include Eskimo or Hawaiian people.

natural resource

Noun

a material that humans have from the natural environment to survive, to satisfy their needs, or to trade with others.

neglect

Substantive

failure to pay attending.

negotiate

Verb

to discuss with others of different viewpoints in order to reach an agreement, contract, or treaty.

nitrate

Substantive

type of table salt used as fertilizer. Excess nitrates can choke freshwater ecosystems.

nitrogen

Noun

chemical element with the symbol N, whose gas course is 78% of the Earth's temper.

nocturnal

Adjective

agile at night.

nomad

Noun

person who moves from place to place, without a fixed dwelling house.

nomadic

Adjective

having to practice with a fashion of life lacking permanent settlement.

notable

Describing word

important or impressive.

Noun

substance an organism needs for energy, growth, and life.

nutrition

Substantive

process by which living organisms obtain food or nutrients, and use it for growth.

Noun

area fabricated fertile past a source of fresh water in an otherwise arid region.

oil reserve

Noun

petroleum from a specific reservoir that can be successfully brought to the surface.

oleander

Noun

shrub cultivated for its flowers.

organism

Noun

living or once-living affair.

Outback

Noun

remote, sparsely populated interior region of Australia.

overcultivation

Noun

process of growing as well many crops in too short a time period on i area of country.

overgrazing

Noun

process of too many animals feeding on one surface area of pasture or grassland.

oxygen

Noun

chemical element with the symbol O, whose gas course is 21% of the World'due south atmosphere.

pack animate being

Substantive

domesticated animal used past humans for transporting appurtenances.

Patagonia

Noun

large plateau in southern South America, stretching from the Andes Mountains to the Atlantic Ocean.

Noun

process past which plants turn h2o, sunlight, and carbon dioxide into water, oxygen, and elementary sugars.

Noun

big region that is higher than the surrounding area and relatively flat.

playa

Noun

big, flat expanse of world covered by a thick layer of salt left by an evaporated saline lake or swimming. Also chosen a table salt apartment, sink, or salt pan.

polar desert

Noun

arid area found in the Arctic or Antarctic.

Noun

all forms in which water falls to Globe from the atmosphere.

prevailing wind

Substantive

air current that blows from one management.

primary

Adjective

first or most important.

profit

Noun

coin earned after product costs and taxes are subtracted.

Noun

dry out land on the side of a mountain facing away from prevailing winds.

rain shadow desert

Noun

barren area found on the leeward side of mountain ranges.

receive

Verb

to get or have.

resource

Noun

bachelor supply of materials, goods, or services. Resource can exist natural or human.

Substantive

large stream of flowing fresh water.

root system

Noun

all of a plant'southward roots.

rural

Adjective

having to do with land life, or areas with few residents.

Sahara Desert

Noun

world's largest desert, in north Africa.

Sahel

Noun

transition zone in northern Africa betwixt the Sahara Desert in the n and the savanna ecosystems in the south.

table salt flat

Substantive

large, flat expanse of earth covered by a thick layer of table salt left past an evaporated saline lake or pond. Likewise called a playa, sink, or common salt pan.

sand

Noun

small, loose grains of disintegrated rocks.

scorching

Adjective

very hot.

scour

Verb

to rub harshly, oft to smoothen.

slash-and-burn

Noun

method of agriculture where copse and shrubs are cleared and burned to create cropland.

snowbird

Noun

person who migrates to warm, dry climates in the winter and to cool, dry climates in the summer.

snowmelt

Noun

water supplied by snow.

sound barrier

Noun

speed of sound, 343 meters per second (one,125 anxiety per second).

spa

Noun

facility, usually with mineral hot springs, offer health benefits.

spring

Noun

small period of h2o flowing naturally from an underground water source.

stomata

Plural Noun

(singular: stoma) tiny openings on the surface of leaves that command the exchange of gases in a plant.

straw

Substantive

stalks of grain.

subtropical desert

Noun

arid area constitute near the Tropic of Cancer and the Tropic of Capricorn, formed by the circulation of air masses. Also chosen a midlatitude desert.

saccharide cane

Noun

tall grass that is harvested to excerpt sugar from its sap or juice.

Noun

use of resources in such a style that they volition never be exhausted.

Substantive

degree of hotness or coldness measured by a thermometer with a numerical calibration.

thobe

Noun

long, loose robe or tunic made of thin material, usually white and worn by Arabic men.

thunderstorm

Substantive

cloud that produces thunder and lightning, often accompanied by heavy rains.

topsoil

Noun

the most valuable, upper layer of soil, where almost nutrients are found.

Tropic of Cancer

Noun

line of latitude 23.5 degrees due north of the Equator.

Tropic of Capricorn

Noun

line of breadth 23.5 degrees s of the Equator.

turban

Noun

man'southward head covering consisting of a long slice of cloth wrapped around a cap or effectually the head.

unique

Adjective

one of a kind.

Noun

developed, densely populated area where most inhabitants have nonagricultural jobs.

Noun

metropolis expanse that is ever warmer than the surrounding area.

vapor

Noun

visible liquid suspended in the air, such equally fog.

vegetation

Substantive

all the plant life of a specific place.

versatile

Adjective

able to accommodate to different conditions.

vulnerable

Adjective

capable of beingness hurt.

wadi

Noun

deep channel or coulee, often dry except during wink floods. As well called an approach.

water rights

Plural Noun

right of a consumer (person, business organisation, or government) to use h2o from a specific source. Sometimes, water rights include the amount of water a consumer is allowed to use.

weather station

Noun

expanse with tools and equipment for measuring changes in the atmosphere.

Noun

area of land covered by shallow water or saturated by water.

whitewater

Noun

fast-moving parts of a river.

Noun

movement of air (from a high pressure zone to a low force per unit area zone) caused by the uneven heating of the Globe by the sun.

windbreak

Noun

construction that serves to interrupt an air current or menses of air current.

windward

Adjective

facing or toward the wind.

xerocole

Noun

fauna that has adapted to live in the desert.

  • Credits

    Media Credits

    The audio, illustrations, photos, and videos are credited beneath the media nugget, except for promotional images, which generally link to another folio that contains the media credit. The Rights Holder for media is the person or group credited.

    Writers

    Diane Boudreau
    Melissa McDaniel
    Erin Sprout
    Andrew Turgeon

    Illustrators

    Mary Crooks, National Geographic Society
    Tim Gunther, Illustrator

    Editors

    Jeannie Evers, Emdash Editing
    Kara W

    Educator Reviewer

    Nancy Wynne

    Producer

    Caryl-Sue, National Geographic Society

    Sources

    Dunn, Margery 1000. (Editor). (1989, 1993). "Exploring Your World: The Adventure of Geography." Washington, D.C.: National Geographic Society.

    Final Updated

    Oct. nineteen, 2011

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