Deserts are areas that receive very little precipitation. People often employ the adjectives "hot," "dry," and "empty" to describe deserts, but these words do not tell the whole story. Although some deserts are very hot, with daytime temperatures as high as 54°C (130°F), other deserts accept common cold winters or are common cold year-round. And about deserts, far from existence empty and lifeless, are abode to a variety of plants, animals, and other organisms. People have adjusted to life in the desert for thousands of years.

One thing all deserts take in common is that they are arid, or dry. Virtually experts concur that a desert is an area of land that receives no more than than 25 centimeters (10 inches) of precipitation a year. The amount of evaporation in a desert often profoundly exceeds the annual rainfall. In all deserts, there is little water available for plants and other organisms.

Deserts are constitute on every continent and cover about ane-fifth of Globe'due south country area. They are home to effectually i billion people—one-sixth of the Earth's population.

Although the give-and-take "desert" may bring to listen a sea of shifting sand, dunes cover only about 10 percent of the world'south deserts. Some deserts are mountainous. Others are dry out expanses of rock, sand, or salt flats.

Kinds of Deserts

The world's deserts can be divided into five types—subtropical, coastal, pelting shadow, interior, and polar. Deserts are divided into these types co-ordinate to the causes of their dryness.

Subtropical Deserts
Subtropical deserts are caused by the circulation patterns of air masses. They are found along the Tropic of Cancer, between 15 and 30 degrees north of the Equator, or along the Tropic of Capricorn, between 15 and 30 degrees south of the Equator.

Hot, moist air rises into the atmosphere near the Equator. As the air rises, it cools and drops its moisture as heavy tropical rains. The resulting libation, drier air mass moves away from the Equator. As it approaches the tropics, the air descends and warms upwardly again. The descending air hinders the formation of clouds, so very little rain falls on the land below.

The earth'due south largest hot desert, the Sahara, is a subtropical desert in northern Africa. The Sahara Desert is almost the size of the entire continental Us. Other subtropical deserts include the Kalahari Desert in southern Africa and the Tanami Desert in northern Australia.

Coastal Deserts
Cold bounding main currents contribute to the formation of coastal deserts. Air blowing 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 ordinarily crusade rainfall are not nowadays. A coastal desert may be almost totally rainless, withal damp with fog.

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

Rain Shadow Deserts
Pelting shadow deserts be near the leeward slopes of some mountain ranges. Leeward slopes face away from prevailing winds.

When wet-laden air hits a mountain range, information technology is forced to rise. The air then cools and forms clouds that drop moisture on the windward (current of air-facing) slopes. When the air moves over the mountaintop and begins to descend the leeward slopes, there is little moisture left. The descending air warms up, making it difficult for clouds to class.

Expiry Valley, in the U.South. states of California and Nevada, is a pelting shadow desert. Death Valley, the lowest and driest place in North America, is in the rain shadow of the Sierra Nevada mountains.

Interior Deserts
Interior deserts, which are found in the heart of continents, be considering no moisture-laden winds reach them. By the fourth dimension air masses from coastal areas accomplish the interior, they accept lost all their moisture. Interior deserts are sometimes chosen inland deserts.

The Gobi Desert, in China and Mongolia, lies hundreds of kilometers from the sea. Winds that reach the Gobi have long since lost their moisture. The Gobi is also in the pelting shadow of the Himalaya mountains to the south.

Polar Deserts
Parts of the Arctic and the Antarctic are classified as deserts. These polar deserts contain nifty quantities of h2o, but nearly of it is locked in glaciers and ice sheets year-round. Then, despite the presence of millions of liters of water, there is really petty available for plants and animals.

The largest desert in the globe is also the coldest. Almost the entire continent of Antarctica is a polar desert, experiencing niggling precipitation. Few organisms tin can withstand the freezing, dry out climate of Antarctica.

Changing Deserts

The regions that are deserts today were not always and then dry out. Between 8000 and 3000 BCE, for instance, the Sahara had a much milder, moister climate. Climatologists identify this period as the "Green Sahara."

Archaeological bear witness of by settlements is arable in the center of what are barren, unproductive areas of the Sahara today. This bear witness includes rock paintings, graves, and tools. Fossils and artifacts bear witness that lime and olive copse, oaks, and oleanders one time bloomed in the Sahara. Elephants, gazelles, rhinos, giraffes, and people used stream-fed pools and lakes.

In that location were three or 4 other moist periods in the Sahara. Similar lush weather existed as recently as 25,000 years agone. Between the moist periods came periods of dryness much similar today'southward.

The Sahara is non the only desert to take dramatic climate change. The Ghaggar River, in what is at present India and Pakistan, was a major water source for Mohenjo-daro, an urban area of the aboriginal Indus Valley Civilisation. Over fourth dimension, the Ghaggar changed course and now but flows during the rainy monsoon season. Mohenjo-daro is now a part of the vast Thar and Cholistan deserts.

Most of Earth'due south deserts will keep to undergo periods of climatic change.

Desert Characteristics

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

Desert humidity is usually so low that non enough water vapor exists to grade clouds. The sun'due south rays beat down through cloudless skies and bake the state. The footing heats the air so much that air rises in waves yous tin can actually see. These shimmering waves confuse the center, causing travelers to encounter distorted images called mirages.

Temperature extremes are a feature of nearly deserts. In some deserts, temperatures rising so loftier that people are at risk of aridity and even death. At night, these areas cool quickly because they lack the insulation provided by humidity and clouds. Temperatures can drop to 4°C (40°F) or lower.

In the Chihuahuan Desert, in the United States and Mexico, temperatures can vary past dozens of degrees in ane day. Daytime temperatures in the Chihuahua tin climb beyond 37°C (100°F), while nighttime temperatures can dip beneath freezing (0°C or 32°F).

Winds at speeds of about 100 kilometers per hour (60 miles per hour) sweep through some deserts. With footling vegetation to block it, the wind can carry sand and grit beyond entire continents and fifty-fifty oceans. Windstorms in the Sahara hurl so much fabric into the air that African dust sometimes crosses the Atlantic Ocean. Sunsets on the Atlantic coast of the U.S. state of Florida, for instance, can be tinted yellow.

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

Water helps carve desert lands. During a sudden storm, h2o scours the dry, difficult-baked land, gathering sand, rocks, and other loose fabric equally it flows. As the muddy h2o roars downhill, it cuts deep channels, called arroyos or wadis. A thunderstorm tin can ship a fast-moving torrent of water—a flash inundation—down a dry arroyo. A wink flood similar this can sweep away anything and anyone in its path. Many desert regions discourage visitors from hiking or camping ground in arroyos for this reason.

Fifty-fifty urban areas in deserts tin be vulnerable to wink floods. The metropolis of Jeddah, Saudi Arabia, sits in the Arabian Desert. In 2011, Jeddah was struck past a sudden thunderstorm and flash flood. Roads and buildings were washed away, and more than 100 people died.

Even in a desert, water and wind eventually wear abroad softer stone. Sometimes, rock is carved into tablelike formations such as mesas and buttes. At the pes of these formations, water drops its burden of gravel, sand, and other sediment, forming deposits called alluvial fans.

Many deserts accept no drainage to a river, lake, or ocean. Rainwater, including h2o from flash floods, collects in large depressions called basins. The shallow lakes that form in basins eventually evaporate, leaving playas, or table salt-surfaced lake beds. Playas, too called sinks, pans, or salt flats, tin exist hundreds of kilometers broad.

The Blackness Rock Desert in the U.South. state of Nevada, for instance, is all that remains of the prehistoric Lake Lahontan. The difficult, flat surface of desert salt flats are often ideal for car racing. In 1997, British airplane pilot Andy Green gear up the state speed tape in Black Stone Desert—1,228 kilometers per hour (763 miles per hour). Green's vehicle, the ThrustSSC, was the first car to intermission the sound bulwark.

Wind is the primary sculptor of a desert's hills of sand, chosen dunes. Wind builds dunes that rise as high as 180 meters (590 anxiety). Dunes drift constantly with the current of air. They usually shift a few meters a year, simply a peculiarly violent sandstorm can move a dune 20 meters (65 feet) in a unmarried day.

Sandstorms may bury everything in their path—rocks, fields, and fifty-fifty towns. Ane legend holds that the Persian Emperor Cambyses 2 sent an ground forces of 50,000 men to the Siwa Haven in western Arab republic of egypt around 530 BCE. Halfway in that location, an enormous sandstorm swallowed the entire group. Archaeologists in the Sahara have been unsuccessfully looking for the "Lost Regular army of Cambyses" e'er since.

H2o in the Desert

Rain is normally the main source of h2o in a desert, but information technology falls very rarely. Many desert dwellers rely on groundwater, stored in aquifers below the surface. Groundwater comes from rain or other precipitation, like snow or hail. It seeps into the basis, where it can remain for thousands of years.

Secret water sometimes rises to the surface, forming springs or seeps. A fertile green surface area called an oasis, or cienega, may be virtually such a water source. Almost 90 major, inhabited oases dot the Sahara. These oases are supported by some of the world's largest supplies of surreptitious water. People, animals, and plants all environs 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 go to it. Many desert cities, from the American Southwest to the Middle East, rely heavily on such aquifers to make full their water needs. Rural Israeli communities called kibbutzim rely on aquifers to furnish water for crops and even fish farming in the dry Negev Desert.

Drilling into aquifers provides water for drinking, agriculture, manufacture, and hygiene. However, information technology comes at a cost to the environment. Aquifers take a long time to refill. If desert communities apply groundwater faster than it is replenished, water shortages tin occur. The Mojave Desert, in southern California and Nevada, for case, is sinking due to aquifer depletion. The booming desert communities of Las Vegas, Nevada, and California's "Inland Empire" are using water faster than the aquifer is being refilled. The water level in the aquifer has sunk every bit much as thirty meters (100 anxiety) since the 1950s, while the land above the aquifer has sunk every bit much as 10 centimeters (iv inches).

Rivers sometimes provide water in a desert. The Colorado River, for instance, flows through three deserts in the American Southwest: the Great Basin, the Sonoran, and the Mojave. 7 states—Wyoming, Colorado, Utah, New Mexico, Nevada, Arizona, and California—rely on the river for some of their h2o supply.

People often modify rivers to help distribute and store water in a desert. The Nile River ecosystem dominates the eastern role of the Sahara Desert, for case. 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 part of the river, almost Arab republic of egypt'southward border with Sudan). The Aswan Dam harnesses the power of the Nile for hydroelectricity used in industry. Information technology also stores water in a manmade lake, Lake Nasser, to protect the state's communities and agriculture against drought.

Structure of the Aswan High Dam was a huge engineering project. Local desert communities tin can divert rivers on a smaller scale. Throughout the Middle East, communities have dug artificial wadis, where freshwater tin flow during rainy seasons. In countries similar Yemen, artificial wadis tin carry enough h2o for whitewater rafting trips during certain times of the yr.

When deserts and water supplies cross state and national borders, people oftentimes fight over water rights. This has happened among united states of america in the Colorado River Bowl, which take 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 ecology impact of dams was non considered when the structures were built. States of the Colorado River Basin continue to negotiate today to gear up for population growth, agricultural development, and the possibility of future droughts.

Life in the Desert

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

In some deserts, plants take unique leaves to capture sunlight for photosynthesis, the procedure plants employ to make food. Small pores in the leaves, chosen stomata, take in carbon dioxide. When they open up, they likewise release h2o vapor. In the desert, all these stomata would apace dry out a plant. So desert plants typically have tiny, waxy leaves. Cactuses accept no leaves at all. They produce nutrient in their green stems.

Some desert plants, such as cactuses, take shallow, wide-spreading root systems. The plants soak up water speedily and store it in their cells. Saguaro cactuses, which alive in the Sonoran Desert of Arizona and northern United mexican states, aggrandize like accordions to store water in the cells of their trunks and branches. A big saguaro is a living storage tower that can hold hundreds of liters of water.

Other desert plants have very deep roots. The roots of a mesquite tree, for example, can reach water more than thirty meters (100 feet) underground.

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

Many desert plants are annuals, which means they only live for one season. Their seeds may prevarication dormant for years during long dry out spells. When rain finally comes, the seeds sprout rapidly. Plants abound, bloom, produce new seeds, and die, oft in a curt bridge of fourth dimension. A soaking rain can change a desert into a wonderland of flowers most overnight.

Animals that accept adapted to a desert environment are called xerocoles. Xerocoles include species of insects, reptiles, birds, and mammals. Some xerocoles avoid the sun by resting in scarce shade. Many escape the heat in cool burrows they dig in the ground. The fennec fox, for example, is native to the Sahara Desert. Fennec pull a fast one on communities work together to dig large burrows, some as large as 93 square meters (ane,000 square feet). Dew tin can collect in these burrows, providing the foxes with fresh water. Yet, fennec foxes take adjusted so they exercise non have to potable water at all: Their kidneys retain plenty h2o from the food they consume.

Most xerocoles are nocturnal. They sleep through the hot days and practice their hunting and foraging at night. Deserts that seem desolate during the twenty-four hours are very active in the cool nighttime air. Foxes, coyotes, rats, and rabbits are all nocturnal desert mammals. Snakes and lizards are familiar desert reptiles. Insects such equally moths and flies are arable in the desert. Most desert birds are restricted to areas almost water, such as river banks. However, some birds, such as the roadrunner, have adjusted 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'southward thick crush insulates the beast and reduces h2o loss. Sand lizards, native to the deserts of Europe and Asia, are nicknamed "dancing lizards" because of the way they rapidly lift one leg at a time off the hot desert sand. A jackrabbit's long ears contain claret vessels that release heat. Some desert vultures urinate on their own legs, cooling them by evaporation.

Many desert animals have developed ingenious means of getting the water they demand. The thorny devil, a cadger that lives in the Australian Outback, has a organisation of tiny grooves and channels on its body that lead to its rima oris. The lizard catches rain and dew in these grooves and sucks them into its mouth by gulping.

Camels are very efficient water users. The animals do not store water in their humps, as people once believed. The humps shop fatty. Hydrogen molecules in the fatty combine with inhaled oxygen to course water. During a shortage of food or water, camels draw upon this fat for diet and moisture. Dromedary camels, native to the Arabian and Sahara deserts, can lose upwards to xxx pct of their torso weight without harm. Camels, nicknamed "ships of the desert," are widely used for transportation, meat, and milk in the Maghreb (a region in Northwest Africa), the Eye East, and the Indian Subcontinent.

People and the Desert

About i billion people live in deserts. Many of these people rely on centuries-old customs to make their lives as comfortable equally possible

Civilizations throughout the Eye East and Maghreb have adapted their vesture to the hot, dry conditions of the Sahara and Arabian deserts. Wear is versatile and based on robes made of rectangles of fabric. Long-sleeved, full-length, and ofttimes white, these robes shield all but the head and hands from the current of air, sand, heat, and cold. White reflects sunlight, and the loose fit allows cooling air to flow across the peel.

These robes of loose fabric tin be adjusted (folded) for length, sleeves, and pockets, depending on the wearer and the climate. A thobe is a total-length, long-sleeved white robe. An abaya is a sleeveless cloak that protects the wearer from grit and heat. A djebba is a short, foursquare pullover shirt worn by men. A kaffiyeh is a rectangular piece of cloth folded loosely around the caput to protect the wearer from sun exposure, dust, and sand. Information technology can be folded and unfolded to cover the mouth, nose, and eyes. Kaffiyehs are secured around the caput with a cord chosen an agal. A turban is similar to a kaffiyeh, but wrapped around the head instead of beingness secured with an agal. Turbans are too much longer—up to six meters (20 feet)!

Desert dwellers have also adapted their shelters for the unique climate. The ancient Anasazi peoples of the southwestern United States and northern United mexican states synthetic huge apartment complexes in the rocky cliffs of the Sonoran Desert. These cliff dwellings, sometimes dozens of meters off the basis, were constructed with thick, earthen walls that provided insulation. Although temperatures outside varied greatly from day to night, temperatures inside did non. Tiny, high windows let in but a little light and helped keep out grit and sand.

The need to find food and water has led many desert civilizations to become nomadic. Nomadic cultures are those that do not accept permanent settlements. In the deserts of the Centre Due east and Asia, nomadic tent communities keep to flourish. Tent walls are made of thick, sturdy cloth that can go along out sand and dust, but also allow cool breezes to blow through. Tents can be rolled up and transported on pack animals (usually horses, donkeys, or camels). Nomads move frequently and so their flocks of sheep and goats volition have water and grazing land.

Likewise animals like camels and goats, a multifariousness of desert vegetation is found 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 resource brought from more fertile areas—food trucked in from afar farmlands or, more ofttimes, water piped from wetter regions. Large areas of desert soil are irrigated by water pumped from secret sources or brought past canal from distant rivers or lakes. The booming Inland Empire of southeastern California is made up of deserts (the Mojave and the Sonoran) that rely on water for agriculture, industry, 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 north.

A variety of crops can thrive in these irrigated oases. Carbohydrate cane is a very water-intensive crop mostly harvested in tropical regions. However, sugar cane is also harvested in the deserts of Pakistan and Australia. Water for irrigation is transported from hundreds of kilometers away, or drilled from hundreds of meters underground.

Oases in desert climates have been popular spots for tourists for centuries. Spas ring the Dead Sea, a saline lake in the Judean Desert of Israel and 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 fifty-fifty 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 every bit Death Valley National Park, California, attract thousands of visitors every year. People who drift to the warm, dry out desert for the winter and render 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 dominicus. But in cities, structures like buildings, roads, and parking lots concur on to daytime estrus long afterward the sunday sets. The temperature stays high even at night, making the city an "island" of estrus in the middle of the desert. This is called the urban heat island effect. Information technology is less pronounced in desert cities than cities congenital in heavily forested areas.  Cities like New York City, New York, and Atlanta, Georgia, tin be 5 degrees warmer than the surrounding area. New York was congenital on wetland habitat, and Atlanta was built in a wooded area. Cities like Phoenix, Arizona, or State of kuwait City, Kuwait, have a much smaller urban heat island effect. They may be only slightly warmer than the surrounding desert.

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

Desertification

Desertification is the procedure of productive cropland turning into non-productive, desert-like environments. Desertification usually happens in semi-arid areas that edge deserts.

Man activities are a main 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 outcome, current of air and water erode the nutrient-rich topsoil. Hooves from grazing livestock meaty the soil, preventing information technology from absorbing water and fertilizers. Agronomical production is devastated, and the economy of a region suffers.

The deserts of Patagonia, the largest in Due 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 take 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 economical opportunities, farmers in Madagascar engaged in slash-and-burn down agriculture. This method relies on cutting and burning forests to create fields for crops. Unfortunately, at the time farmers were investing in slash-and-fire agriculture, Republic of madagascar experienced long-term droughts. With trivial vegetation to ballast it, the thin topsoil quickly eroded. The island'due south central plateau is now a barren desert.

Rapid population growth likewise can atomic number 82 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 utilise Lake Chad's shallow waters for agriculture, manufacture, and hygiene. Since the 1960s, Lake Republic of 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. In the 1930s, parts of the Great Plains of N America became the "Grit Bowl" through a combination of drought and poor farming practices. Millions of people had to exit their farms and seek a living in other parts of the country.

Desertification is an increasing problem. Every twelvemonth, well-nigh 6 million square kilometers (2.3 million square miles) of land become useless for cultivation due to desertification. The Sahara Desert crept 100 kilometers (39 miles) s between 1950 and 1975. South Africa is losing 300-400 million metric tons (330-441 brusk tons) of topsoil each year.

Many countries are working to reduce the rates of desertification. Trees and other vegetation are being planted to intermission the strength of the air current and to hold the soil. Windbreaks fabricated 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.

In China's Tengger Desert, researchers have developed another way to control wandering dunes. They anchor the drifting sand with a gridlike network of harbinger fences. Straw is poked partway into the sand, forming a pattern of small squares along the contours of the dunes. The resulting fences interruption the force of the wind at footing level, stopping dune movement by confining the sand within the squares of the grid.

New technologies are likewise being adult to combat desertification. "Nanoclay" is a substance sprayed on desert sands that acts as a binding agent. Nanoclay keeps the sand moist, clumping it together and preventing it from bravado away.

Deserts Get Hotter

Rise temperatures can have huge effects on fragile desert ecosystems. Global warming is the about current example of climate change. Human being activities such as called-for fossil fuels 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 microbes from converting nutrients to nitrates, which are necessary for well-nigh all living things. This tin can reduce the already limited plant life in deserts.

Climate alter also affects rainfall patterns. Climate scientists predict that global warming will lead to more rainfall in some regions, only less rainfall in other places. Areas facing reduced precipitation include areas with some of the largest deserts in the earth: North Africa (Sahara), the American Southwest (Sonoran and Chihuahuan), the southern Andes (Patagonia), and western Commonwealth of australia (Slap-up Victoria).

In literature and in legend, deserts are often described every bit 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 proper noun.

Hot and Cold Deserts
The largest hot desert in the world is the Sahara, which is 9 million square kilometers (3.v million square miles). Information technology isn't the hottest place on Earth, though. That distinction belongs to Death Valley, in California's Mojave Desert. The highest temperature on World was recorded there: 56.7 C (134.1 F).

The largest polar desert is Antarctica, at thirteen million foursquare kilometers (v meg square miles). Antarctica boasts the lowest official temperature recorded on Earth: -89.2 C (-128.6 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 death just to be reborn, ascent from its ain ashes. The urban center of Phoenix was built on meridian 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 too 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 go very hot, the heated air above them begins to ascent and spin. This whirling column of hot air picks up dust and dirt. These spinning columns of clay can rising hundreds of feet in the air.

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

abaya

Substantive

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

accessibility

Noun

the ease with which a identify or thing can be reached from other places.

conform

Verb

to arrange to new surroundings or a new situation.

agal

Noun

string wrapped around a kaffiyeh, or head covering, to go on it in place.

agricultural evolution

Noun

modern farming methods that include mechanical, chemic, applied science and technological methods. Also called industrial agronomics.

Substantive

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

air conditioning

Substantive

system that cools the air.

Noun

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

Substantive

fan-shaped deposit of eroded material, normally 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 United States. Also called Ancestral Puebloans.

anchor

Verb

to hold firmly in place.

ancient

Adjective

very old.

Antarctic

Noun

region at Earth's extreme south, encompassed by the Antarctic Circle.

aqueduct

Substantive

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

Noun

an hugger-mugger layer of rock or earth which holds groundwater.

aquifer depletion

Substantive

process by which people pump more water out of aquifers than can be replaced by pelting or snow.

archaeological

Adjective

having to practise with the report of ancient people and cultures.

archaeologist

Noun

person who studies artifacts and lifestyles of ancient cultures.

Noun

region at Earth'due south extreme north, encompassed by the Arctic Circle.

arroyo

Noun

deep aqueduct or canyon, often dry except during flash floods. Also called a wadi.

Noun

fabric remains of a civilisation, such as tools, wear, or food.

Aswan Dam

Noun

system of ii dams in Egypt that control the menstruation of the Nile River for agricultural, electrical, and sanitary uses.

Atacama Desert

Noun

large, near rainless desert in western South America.

atmospheric changes

Noun

alterations in the layer of air surrounding the Earth, such equally an increment of pollution or humidity.

Noun

a dip or depression in the surface of the country or bounding main flooring.

Noun

all the dissimilar kinds of living organisms within a given area.

biologist

Noun

scientist who studies living organisms.

burrow

Noun

pocket-size pigsty or tunnel used for shelter.

Noun

unmarried hill or rock formation that rises sharply from a flat landscape, ordinarily in a desert.

cactus

Noun

type of plant native to dry out regions.

Cambyses II

Noun

(?-522 BCE) emperor of Persia.

canal

Substantive

artificial waterway.

Substantive

deep, narrow valley with steep sides.

carbon dioxide

Noun

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

cattle

Substantive

cows and oxen.

prison cell

Substantive

smallest working part of a living organism.

feature

Substantive

physical, cultural, or psychological feature of an organism, identify, or object.

cienega

Noun

haven or swampy wetland, usually fed by natural springs.

circulation

Substantive

moving in a circular motility.

Substantive

complex way of life that adult as humans began to develop urban settlements.

Noun

steep wall of rock, earth, or water ice.

climate

Noun

all weather conditions for a given location over a catamenia of fourth dimension.

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 droplets or water ice crystals in Earth's atmosphere.

cloudburst

Noun

sudden, heavy rainfall.

coastal desert

Noun

barren areas usually found on the western edges of continents near the Tropic of Cancer and the Tropic of Capricorn.

Noun

i of the seven main country masses on Earth.

cotton

Substantive

material made from fibers of the cotton plant.

Noun

agronomical produce.

cultivate

Verb

to prepare and nurture the land for crops.

Noun

steady, predictable period of fluid within a larger body of that fluid.

dam

Noun

construction built beyond a river or other waterway to control the flow of water.

Expiry Valley

Noun

(~3,900 foursquare kilometers/1,500 square miles) dry out basin in the U.S. states of California and Nevada, the everyman bespeak in North America (86 meters/282 feet below sea level).

Noun

devastation or removal of forests and their undergrowth.

aridity

Noun

illness in which the body loses too much water.

Substantive

surface area of land 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

arid, spare, or lonely.

devastate

Verb

to destroy.

Substantive

h2o droplets condensed from the atmosphere onto cool surfaces almost the ground.

divert

Verb

to direct away from a familiar path.

djebba

Noun

short, pullover tunic or shirt worn by men.

dominate

Verb

to overpower or control.

dormant

Adjective

country of minimal growth or action.

Noun

period of greatly reduced precipitation.

Substantive

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

Noun

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

Dust Bowl

Substantive

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

economy

Noun

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

Substantive

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

efficient

Adjective

performing a task with skill and minimal waste.

engineering

Noun

the fine art and scientific discipline of edifice, maintaining, moving, and demolishing structures.

enormous

Describing word

very large.

Noun

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

Noun

process by which liquid water becomes water vapor.

exceed

Verb

to get across the limit.

fertile

Describing word

able to produce crops or sustain agriculture.

fertilizer

Noun

food-rich chemical substance (natural or manmade) applied to soil to encourage plant growth.

fishery

Noun

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

fish farming

Substantive

art and science of raising and harvesting fish and other seafood, such every bit shrimp or crabs.

flash overflowing

Substantive

sudden, short, and heavy flow of water.

flourish

Verb

to thrive or be 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

fragile or easily broken.

geologist

Noun

person who studies the physical formations of the World.

Noun

mass of ice that moves slowly over state.

Substantive

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

Gobi Desert

Noun

large desert in Cathay and Mongolia.

government

Noun

organization or order of a nation, country, or other political unit of measurement.

grassland

Noun

ecosystem with large, flat areas of grasses.

grave

Noun

specific place where a body is buried.

gravel

Noun

small stones or pebbles.

grazing animal

Noun

animal that feeds on grasses, trees, and shrubs.

Great Plains

Noun

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

Green Sahara

Noun

(7000-3000 BCE) moist, temperate climate of the present-day Sahara Desert during the Neolithic Subpluvial period. Also called the Wet Sahara.

Noun

water found in an aquifer.

Noun

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

hinder

Verb

to delay or concord back.

hoof

Substantive

thick, horny covering of the feet of animals such equally horses and cattle.

hostile

Describing word

confrontational or unfriendly.

Substantive

amount of water vapor in the air.

hydroelectricity

Noun

power generated past moving h2o converted to electricity. Also called hydroelectric energy or hydroelectric ability.

hydrogen

Noun

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

hygiene

Noun

scientific discipline and methods of keeping make clean and healthy.

Noun

thick layer of glacial ice that covers a big expanse of land.

industry

Noun

activity that produces appurtenances and services.

Indus Valley Civilisation

Substantive

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

ingenious

Adjective

very clever or smart.

Inland Empire

Substantive

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

arid area found in the interior of continents, formed because no moisture-laden winds reach them.

kaffiyeh

Substantive

short headdress worn by Arab men and tied with a string (agal).

kibbutzim

Plural Noun

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

kidney

Noun

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

King David

Substantive

(?1050-970 BCE) rex of ancient State of israel and major religious effigy for Judaism, Christianity, and Islam.

Substantive

the geographic features of a region.

leeward

Adjective

downwind, or facing away from prevailing winds.

legendary

Adjective

famous, heroic, or historic.

literature

Noun

written cloth, including novels, poetry, drama and history.

livestock

Noun

animals raised for human employ.

lush

Describing word

abundant and rich.

Maghreb

Noun

region in North Africa made of five countries: Morocco, Algeria, Tunisia, Libya, and Mauritania.

Noun

broad, flat-topped landform with steep sides.

mesquite

Noun

tree or shrub native to the hot deserts of Due north America.

microbe

Noun

tiny organism, usually a bacterium.

Heart East

Substantive

region of southwest Asia and northeast Africa.

migrate

Verb

to move from one place or activity to some other.

delusion

Noun

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

modify

Verb

to change or alter.

Mohenjo-daro

Noun

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

molecule

Substantive

smallest concrete unit of a substance, consisting of 2 or more atoms linked together.

Noun

seasonal change in the direction of the prevailing winds of a region. Monsoon commonly refers to the winds of the Indian Body of water and Southward Asia, which often bring heavy rains.

mountain range

Substantive

series or concatenation of mountains that are close together.

nanoclay

Substantive

collection of tiny particles that acts every bit a bounden agent to materials such equally sand or plastics.

Native American

Noun

person whose ancestors were native inhabitants of North or South America. Native American usually does non include Eskimo or Hawaiian people.

natural resources

Substantive

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

neglect

Noun

failure to pay attention.

negotiate

Verb

to hash out with others of different viewpoints in order to attain an understanding, contract, or treaty.

nitrate

Noun

type of salt used every bit fertilizer. Excess nitrates tin choke freshwater ecosystems.

nitrogen

Substantive

element with the symbol N, whose gas form is 78% of the Earth'southward temper.

nocturnal

Adjective

agile at night.

nomad

Noun

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

nomadic

Adjective

having to do with a way of life lacking permanent settlement.

notable

Describing word

important or impressive.

Substantive

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

nutrition

Noun

process past which living organisms obtain food or nutrients, and use information technology for growth.

Noun

area made fertile by a source of fresh water in an otherwise arid region.

oil reserve

Substantive

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 matter.

Outback

Noun

remote, sparsely populated interior region of Commonwealth of australia.

overcultivation

Noun

process of growing too many crops in too short a time catamenia on one area of land.

overgrazing

Noun

process of as well many animals feeding on i area of pasture or grassland.

oxygen

Substantive

chemical element with the symbol O, whose gas form is 21% of the Earth's atmosphere.

pack animal

Substantive

domesticated animal used past humans for transporting goods.

Patagonia

Noun

large plateau in southern S America, stretching from the Andes Mountains to the Atlantic Sea.

Substantive

process past which plants plow water, sunlight, and carbon dioxide into water, oxygen, and simple sugars.

Noun

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

playa

Substantive

large, flat surface area of earth covered by a thick layer of common salt left by an evaporated saline lake or pond. Likewise chosen a table salt flat, sink, or salt pan.

polar desert

Substantive

arid surface area establish in the Arctic or Antarctic.

Substantive

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

prevailing wind

Noun

wind that blows from one direction.

primary

Adjective

first or most important.

turn a profit

Noun

coin earned after production costs and taxes are subtracted.

Substantive

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

rain shadow desert

Noun

arid expanse found on the leeward side of mountain ranges.

receive

Verb

to get or accept.

resources

Substantive

available supply of materials, goods, or services. Resources can exist natural or human.

Noun

large stream of flowing fresh water.

root arrangement

Noun

all of a establish's roots.

rural

Adjective

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

Sahara Desert

Noun

world'due south largest desert, in n Africa.

Sahel

Noun

transition zone in northern Africa between the Sahara Desert in the north and the savanna ecosystems in the s.

salt apartment

Noun

large, flat expanse of world covered by a thick layer of salt left by an evaporated saline lake or pond. Besides called a playa, sink, or salt pan.

sand

Noun

small, loose grains of disintegrated rocks.

scorching

Adjective

very hot.

scour

Verb

to rub harshly, often to shine.

slash-and-fire

Noun

method of agriculture where trees 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 summertime.

snowmelt

Noun

water supplied by snow.

sound barrier

Substantive

speed of sound, 343 meters per second (1,125 feet per 2d).

spa

Noun

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

spring

Substantive

small flow of water flowing naturally from an underground water source.

stomata

Plural Noun

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

straw

Noun

stalks of grain.

subtropical desert

Substantive

arid surface area institute most the Tropic of Cancer and the Tropic of Capricorn, formed by the circulation of air masses. Also called a midlatitude desert.

sugar cane

Noun

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

Noun

use of resources in such a manner that they will never be wearied.

Noun

degree of hotness or coldness measured past a thermometer with a numerical scale.

thobe

Noun

long, loose robe or tunic made of sparse fabric, ordinarily white and worn by Arabic men.

thunderstorm

Noun

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

topsoil

Noun

the well-nigh valuable, upper layer of soil, where most nutrients are institute.

Tropic of Cancer

Noun

line of latitude 23.5 degrees north of the Equator.

Tropic of Capricorn

Noun

line of latitude 23.5 degrees south of the Equator.

turban

Substantive

man's caput covering consisting of a long piece of fabric wrapped around a cap or around the head.

unique

Adjective

one of a kind.

Noun

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

Noun

city expanse that is always warmer than the surrounding surface area.

vapor

Noun

visible liquid suspended in the air, such as fog.

vegetation

Noun

all the constitute life of a specific identify.

versatile

Adjective

able to adjust to different conditions.

vulnerable

Adjective

capable of being hurt.

wadi

Substantive

deep channel or canyon, often dry except during flash floods. Also called an arroyo.

water rights

Plural Noun

right of a consumer (person, business concern, or regime) to use water from a specific source. Sometimes, water rights include the amount of water a consumer is immune to apply.

conditions station

Noun

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

Noun

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

whitewater

Noun

fast-moving parts of a river.

Noun

motion of air (from a high pressure zone to a low pressure zone) caused by the uneven heating of the Earth past the sunday.

windbreak

Noun

structure that serves to interrupt an air current or flow of wind.

windward

Adjective

facing or toward the wind.

xerocole

Substantive

animate being that has adjusted 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 mostly link to another page that contains the media credit. The Rights Holder for media is the person or grouping 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 One thousand. (Editor). (1989, 1993). "Exploring Your World: The Gamble of Geography." Washington, D.C.: National Geographic Order.

    Last Updated

    Oct. xix, 2011

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