Desert (2024)

Deserts are areas that receive very little precipitation. People often use 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

have cold winters or are cold year-round. And most

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.

One thing all

deserts

have in common is that they are arid, or dry. Most experts agree that a

desert

is an area of land that

receives

no more than 25 centimeters (10 inches) of

precipitation

a year. 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 cover about one-fifth of Earth’s land area. They are home to around 1 billion people—one-sixth of the Earth’s population.

Although the word “

desert

” may bring to mind a sea of shifting

sand

, dunes cover only about 10 percent of the world’s

deserts

. Some

deserts

are mountainous. Others are dry expanses of rock,

sand

, or salt flats.

Kinds of Deserts

The world’s

deserts

can be divided into five types—subtropical, coastal, rain shadow, interior, and polar.

Deserts

are divided into these types according 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 cooler, drier

air mass

moves away from the

Equator

. As it approaches the tropics, the air descends and warms up again. The descending air hinders the formation of clouds, so very little rain falls on the land below.

The world’s largest hot

desert

, the Sahara, is a

subtropical

desert

in northern Africa. The Sahara Desert is almost 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 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 normally cause rainfall are not present. A

coastal

desert

may be almost totally rainless, yet 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 can 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
Rain shadow

deserts

exist near the leeward slopes of some mountain ranges.

Leeward

slopes face away from prevailing winds.

When moisture-laden air hits a

mountain range

, it is forced to rise. The air then cools and forms

clouds

that drop moisture on the windward (wind-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 form.

Death Valley, in the U.S. states of California and Nevada, is a

rain 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

, exist because no moisture-laden

winds

reach them. By the time

air masses

from coastal areas reach the interior, they have lost all their moisture.

Interior

deserts

are sometimes called inland

deserts

.

The Gobi Desert, in China and Mongolia, lies hundreds of kilometers from the ocean.

Winds

that reach the Gobi have long since lost their moisture. The Gobi is also in the

rain 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 great quantities of water, but most of it is locked in glaciers and ice sheets year-round. So, despite the presence of millions of liters of water, there is actually little available for plants and animals.

The largest

desert

in the world is also the coldest. Almost the entire

continent

of

Ant

arctica

is a

polar

desert

, experiencing little

precipitation

. Few

organisms

can withstand the freezing, dry climate of

Ant

arctica

.

Changing Deserts

The regions that are

deserts

today were not always so dry. Between 8000 and 3000 BCE, for example, the Sahara had a much milder, moister

climate

. Climatologists identify this period as the “Green Sahara.”

Archaeological evidence 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. Similar lush conditions existed as recently as 25,000 years ago. Between the moist periods came periods of dryness much like today’s.

The Sahara is not the only

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 area of the ancient Indus Valley Civilization. Over time, the Ghaggar changed course and now only flows during the rainy monsoon season.

Mohenjo-daro

is now a part of the vast Thar and Cholistan

deserts

.

Most of Earth’s

deserts

will continue to undergo periods of

climate

change

.

Desert Characteristics

Humidity

—water vapor in the air—is near zero in most

deserts

. Light rains often e

vaporate

in the dry air, never reaching the ground. Rainstorms sometimes come as violent cloudbursts. A

cloudburst

may bring as much as 25 centimeters (10 inches) of rain in a single hour—the only rain the

desert

gets all year.

Desert

humidity

is usually so low that not enough water

vapor

exists to form

clouds

. The sun’s rays beat down through

cloudless

skies and bake the land. The ground heats the air so much that air rises in waves you can actually see. These shimmering waves confuse the eye, causing travelers to see distorted images called mirages.

Temperature

extremes are a

characteristic

of most

deserts

. In some

deserts

,

temperatures

rise so high that people are at risk of dehydration 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 by dozens of degrees in one day. 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 hour (60 miles per hour) sweep through some

deserts

. With little vegetation to block it, the

wind

can carry

sand

and dust across entire

continents

and even oceans.

Windstorms

in the Sahara hurl so much material into the air that African

dust

sometimes crosses the Atlantic Ocean. Sunsets on the Atlantic coast of the U.S. state of Florida, for example, 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 often gently rounded by regular rainfall and softened by

lush

vegetation

.

Water helps carve

desert

lands. During a sudden storm, water scours the dry, hard-baked land, gathering

sand

, rocks, and other loose material as it flows. As the muddy water roars downhill, it cuts deep channels, called arroyos or wadis. A thunderstorm can send a fast-moving torrent of water—a flash flood—down a dry

arroyo

. A

flash flood

like this can sweep away anything and anyone in its path. Many

desert

regions di

scourage

visitors from hiking or camping in

arroyos

for this reason.

Even

urban areas

in

deserts

can be vulnerable to

flash floods

. The city of Jeddah, Saudi Arabia, sits in the Arabian

Desert

. In 2011, Jeddah was struck by 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 away softer rock. Sometimes, rock is carved into tablelike formations such as mesas and buttes. At the foot of these formations, water drops its burden of gravel,

sand

, and other sediment, forming deposits called alluvial fans.

Many

deserts

have no drainage to a

river

, lake, or ocean. Rainwater, including water from

flash floods

, collects in large depressions called basins. The shallow lakes that form in

basins

eventually e

vaporate

, leaving playas, or salt-surfaced lake beds.

Playas

, also called sinks, pans, or

salt flats

, can be hundreds of kilometers wide.

The Black Rock

Desert

in the U.S. state of Nevada, for instance, is all that remains of the prehistoric Lake Lahontan. The hard, flat surface of

desert

salt flats

are often ideal for car racing. In 1997, British pilot Andy Green set the land speed record in Black Rock

Desert

—1,228 kilometers per hour (763 miles per hour). Green’s vehicle, the ThrustSSC, was the first car to break the sound barrier.

Wind

is the primary sculptor of a

desert

’s hills of

sand

, called

dunes

.

Wind

builds

dunes

that rise as high as 180 meters (590 feet).

Dunes

migrate constantly with the

wind

. They usually shift a few meters a year, but a particularly violent

sandstorm

can move a

dune

20 meters (65 feet) in a single day.

Sandstorms

may bury everything in their path—rocks, fields, and even towns. One legend holds that the Persian Emperor Cambyses II sent an army of 50,000 men to the Siwa Oasis in western Egypt around 530 BCE. Halfway there, an enormous

sandstorm

swallowed the entire group. Archaeologists in the Sahara have been unsuccessfully looking for the “Lost Army of Cambyses” ever since.

Water in the Desert

Rain 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 rain or other

precipitation

, like snow or hail. It seeps into the ground, where it can remain for thou

sands

of years.

Underground water sometimes rises to the surface, forming springs or seeps. A fertile green area called an

oasis

, or cienega, may exist near such a water source. About 90 major, inhabited oases dot the Sahara. These oases are supported by 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 East, rely heavily on such

aquifers

to fill 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, industry, and hygiene. However, it comes at a cost to the environment.

Aquifers

take a long time to refill. If

desert

communities use

groundwater

faster than it 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 water faster than the

aquifer

is being refilled. The water level in the

aquifer

has sunk as much as 30 meters (100 feet) since the 1950s, while the land above the

aquifer

has sunk as much as 10 centimeters (4 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. 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 help distribute and store water in a

desert

. The Nile

River

ecosystem dominates the eastern part of the

Sahara

Desert

, for instance. The Nile provides the most reliable, plentiful source of freshwater in the region. Between 1958 and 1971, the government of Egypt constructed a massive

dam

on the Upper Nile (the southern part of the

river

, near Egypt’s border with Sudan). The Aswan Dam harnesses the power of the Nile for hydroelectricity used in

in

dustry

. It also stores water in a manmade lake, Lake Nasser, to protect the country’s communities and

agriculture

against drought.

Construction of the Aswan High

Dam

was a huge engineering project. Local

desert

communities can divert

rivers

on a smaller scale. Throughout the

Middle East

, communities have dug artificial

wadis

, where freshwater can flow during rainy seasons. In countries like Yemen, artificial

wadis

can carry enough water for whitewater rafting trips during certain times of the year.

When

deserts

and water supplies cross state and national borders, people often fight over water rights. This has happened among 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 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 impact of

dams

was not considered when the structures were built. States of the Colorado

River

Basin

continue to

negotiate

today to prepare for population growth, agricultural development, and the possibility of future

droughts

.

Life in the Desert

Plants and animals

adapt

to

desert

habitats in many ways.

Desert

plants grow far apart, allowing them to obtain as much water around them as possible. This spacing gives some

desert

regions a desolate appearance.

In some

deserts

, plants have unique leaves to capture sunlight for photosynthesis, the process plants use to make food. Small pores in the leaves, called stomata, take in carbon dioxide. When they open, they also release water

vapor

. In the

desert

, all these

stomata

would quickly dry out a plant. So

desert

plants typically have tiny, waxy leaves. Cactuses have no leaves at all. They produce food in their green stems.

Some

desert

plants, such as

cactuses

, have shallow, wide-spreading root systems. The plants soak up water quickly and store it in their cells. Saguaro

cactuses

, which live in the Sonoran

Desert

of Arizona and northern Mexico, expand like accordions to store water in the

cells

of their trunks and branches. A large 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 30 meters (100 feet) underground.

Mesquites

, saguaros, and many other

desert

plants also have thorns to protect them from grazing animals.

Many

desert

plants are

annuals

, which means they only live for one season. Their seeds may lie dormant for years during long dry spells. When rain finally comes, the seeds sprout rapidly. Plants grow, bloom, produce new seeds, and die, often in a short

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 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 fox communities work together to dig large

burrows

, some as large as 93 square meters (1,000 square feet). Dew can collect in these

burrows

, providing the foxes with fresh water. However, fennec foxes have

adapted

so they do not have to drink water at all: Their kidneys retain enough water from the food they eat.

Most

xerocoles

are nocturnal. They sleep through the hot days and do their hunting and foraging at night.

Deserts

that seem

desolate

during the day 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 as moths and flies are abundant in the

desert

. Most

desert

birds are restricted to areas near water, such as

river

banks. However, 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 quickly lift one leg at a time off the hot

desert

sand

. A jackrabbit’s long ears contain blood vessels that release heat. Some

desert

vultures urinate on their own legs, cooling them by

e

vaporation

.

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 system of tiny grooves and channels on its body that lead to its mouth. 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 store 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 up to 30 percent of their body 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

Middle East

, and the Indian Sub

continent

.

People and the Desert

About 1 billion people live in

deserts

. Many of these people rely on centuries-old customs to make their lives as comfortable as possible

Civilizations throughout the

Middle East

and

Maghreb

have

adapted

their clothing to the hot, dry conditions of the Sahara and Arabian

deserts

. Clothing is versatile and based on robes made of rectangles of fabric. Long-sleeved, full-length, and often white, these robes shield all but the head and hands from the

wind

,

sand

, heat, and cold. White reflects sunlight, and the loose fit allows cooling air to flow across the skin.

These robes of loose cloth can be 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

dust

and heat. A djebba is a short, square pullover shirt worn by men. A kaffiyeh is a rectangular piece of cloth folded loosely around the head to protect the wearer from sun exposure,

dust

, and

sand

. It can be folded and unfolded to cover the mouth, nose, and eyes.

Kaffiyehs

are secured around the head with a cord called an agal. A turban is similar to a

kaffiyeh

, but wrapped around the head instead of being secured with an

agal

.

Turbans

are also 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 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 greatly from day to night,

temperatures

inside did not. Tiny, high

windows

let in only a little light and helped keep out

dust

and

sand

.

The need to find food and water has led many

desert

civilizations

to become nomadic. Nomadic cultures are those that do not have permanent settlements. In the

deserts

of the

Middle East

and Asia,

nomadic

tent communities continue to flourish. Tent walls are made of thick, sturdy cloth that can keep 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 so their flocks of sheep and goats will have water and grazing land.

Besides animals like camels and goats, a variety 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 resources brought from more

fertile

areas—food trucked in from distant farmlands or, more frequently, water piped from wetter regions. Large areas of

desert

soil are irrigated by water pumped from underground sources or brought by 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

,

in

dustry

, and residential development.

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. Sugar 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 made 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, attract thou

sands

of visitors every year. People who

migrate

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. But in cities, structures like buildings, roads, and parking lots hold on to daytime heat long after the sun 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 like New York City, New York, and Atlanta, Georgia, can be 5 degrees warmer than the surrounding area. New York was built on wetland

habitat

, and Atlanta was built in a wooded area. Cities like Phoenix, Arizona, or Kuwait City, Kuwait, have a much smaller

urban heat 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 half of the proven

oil reserves

in the world lie beneath the

sands

of the Arabian

Desert

, mostly in Saudi Arabia. The oil

in

dustry

draws companies, migrant workers, engineers, geologists, and biologists to the

Middle East

.

Desertification

Desertification

is the process of productive

cropland

turning into non-productive,

desert

-like environments.

Desertification

usually happens in semi-

arid

areas that border

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

de

forestation

remove plants that anchor the soil. As a result,

wind

and water erode the nutrient-rich topsoil. Hooves from grazing

livestock

compact the soil, preventing it from absorbing water and fertilizers. Agricultural production is devastated, and the economy of a region suffers.

The

deserts

of Patagonia, the largest in South America, are expanding due to

desertification

.

Patagonia

is a major agricultural region where non-native species such as cattle and sheep graze on grassland. Sheep and

cattle

have reduced the native

vegetation

in

Patagonia

, causing loss of valuable

topsoil

. More than 30 percent of the

grasslands

of Argentina, Chile, and Bolivia are faced with

desertification

.

People often overuse natural resources to survive and profit in the short term, while neglecting long-term sustainability. Madagascar, for instance, is a tropical island in the Indian Ocean. Seeking greater economic opportunities, farmers in Madagascar engaged in slash-and-burn

agriculture

. This method relies on cutting and burning

forests

to create fields for

crops

. Unfortunately, at the time farmers were investing in

slash-and-burn

agriculture

, Madagascar experienced long-term

droughts

. With little

vegetation

to

anchor

it, the thin

topsoil

quickly

eroded

. The island’s central plateau is now a barren

desert

.

Rapid population growth also 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

,

in

dustry

, and

hygiene

. Since the 1960s, Lake Chad has shrunk to half its size.

Desertification

has severely reduced the

wetland

habitats

surrounding the lake, as well as its fishery and grazing lands.

Desertification

is not new. In the 1930s, parts of the Great Plains of North America became the “Dust 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 country.

Desertification

is an increasing problem. Every year, about 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) south between 1950 and 1975. South Africa is losing 300-400 million metric tons (330-441 short tons) of

topsoil

each year.

Many countries are working to reduce the rates of

desertification

. Trees and other

vegetation

are being planted to break the force of the

wind

and to hold the soil. Windbreaks made of trees have been planted throughout the Sahel, the southern border region of the

Sahara

Desert

. These

windbreaks

anchor

the soil and prevent

sand

from invading populated areas.

In China’s Tengger

Desert

, researchers have developed another way to control wandering

dunes

. They

anchor

the drifting

sand

with a gridlike network of straw fences.

Straw

is poked partway into the

sand

, forming a pattern of small squares along the contours of the

dunes

. The resulting fences break the force of the

wind

at ground level, stopping

dune

movement by confining the

sand

within the squares of the grid.

New technologies are also being developed to combat

desertification

. “Nanoclay” 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 blowing away.

Deserts Get Hotter

Rising

temperatures

can have huge effects on fragile

desert

ecosystems

. Global warming is the most

current

instance of

climate

change

. Human activities such as burning fossil 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 almost all living things. This can reduce the already limited plant life in

deserts

.

Climate

change

also affects rainfall patterns.

Climate

scientists predict that

global warming

will lead to more rainfall in some regions, but less rainfall in other places. Areas facing reduced

precipitation

include areas with some of the largest

deserts

in the world: North Africa (Sahara), the American Southwest (Sonoran and Chihuahuan), the southern Andes (

Patagonia

), and western Australia (Great Victoria).

In literature and in legend,

deserts

are often described as hostile places to avoid. Today, people value

desert

resources

and biodiversity. Communities,

governments

, and organizations are working to preserve

desert

habitats

and increase

desert

productivity.

National Geographic Environment: Desert Landscapes

National Geographic Environment: DesertsUSGS: What is a Desert?NASA: Exploration—Desert RATS